System, apparatus, and method for forming an anastomosis

Abstract

Disclosed herein are systems, devices, and methods for treating heart failure. In some variations, a catheter for forming an anastomosis within the heart can include a first catheter including an electrode. A second catheter can be slidably disposed within the first catheter. The second catheter can include a barb and a dilator including a mating surface configured to engage the electrode.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 971,357, filed on February 7, 2020, and U.S. Provisional Patent Application No. 62 / 900,034, filed on September 13, 2019, the contents of each of which are hereby incorporated by reference in their entirety.

[0002] Technical Field

[0002] The devices, systems, and methods herein relate to forming anastomoses, including but not limited to anastomoses within a patient's heart.

Background Art

[0003] Background

[0003] Congestive heart failure (CHF) is characterized by a decrease in myocardial function, which is caused by either a weakening of its pumping ability or a hardening of the myocardium resulting in a reduced ability to adequately distribute blood before ejection. When blood flow from the heart to the organs necessary for life support is insufficient, the renin - angiotensin - aldosterone system (RAAS) is activated, which signals the body to retain body fluids, thereby increasing the pressure within the heart chambers. In particular, when the left atrial pressure (LAP) increases, body fluids can backflow into the pulmonary circulation, which can lead to pulmonary edema and severe shortness of breath. Therefore, additional devices, systems, and methods for treating heart failure are desired.

Summary of the Invention

Means for Solving the Problems

[0004]

[0004] This specification describes devices, systems, and methods for treating heart failure. These devices and systems can form anastomoses within body structures. In some variations, a catheter for forming an anastomosis within the heart can include a first catheter that includes electrodes. A second catheter can be slidably disposed within the first catheter. The second catheter can include a retractor and a dilator that includes a mating surface configured to engage the electrodes.

[0005]

[0005] In some variations, the retractor can be disposed within the lumen of the electrodes when the mating surface engages the electrodes. In some variations, the outer diameter of the dilator can be made smaller than the outer diameter of the electrodes. In some variations, the retractor can be configured to engage tissue.

[0006]

[0006] In some variations, the second catheter can define a longitudinal axis. The retractor can include at least one protrusion that includes a first portion and a second portion. The first portion can be angled with respect to the second portion. The ratio of the length of the first portion to the length of the second portion can be from about 2:3 to about 1:5. In some variations, the second portion can include a length from about 0.1 mm to about 2 cm. The first portion can be angled from about 60 degrees to about 120 degrees with respect to the longitudinal axis. In some variations, the first portion can be substantially perpendicular to the longitudinal axis. In some variations, the second portion can be angled up to about 30 degrees with respect to the longitudinal axis. In some variations, the second portion can be substantially parallel to the longitudinal axis. In some variations, the retractor can include from about 3 protrusions to about 7 protrusions. In some variations, at least one protrusion can include one of an "L" shape, a "J" shape, and a "C" shape. In some variations, at least one protrusion can include a plurality of protrusions configured in a series of concentric rings. In some variations, at least one protrusion can be configured to penetrate tissue.

[0007]

[0007] In some variations, the loop may include one or more protrusions angled from about 5 degrees to about 60 degrees relative to the longitudinal axis. In some of these variations, the one or more protrusions may be configured to form a row along the length of the loop. In some variations, the protrusions may be configured to penetrate tissue and reduce shearing of the tissue. In some variations, the length of the loop may be from about 0.1 mm to about 5 cm. In some variations, the electrode and the mating surface may be configured to compress tissue therebetween. In some variations, the second catheter may define a longitudinal axis, and the mating surface may be non-perpendicular and non-parallel to the longitudinal axis.

[0008]

[0008] In some variations, the first catheter may include an insulator disposed over a portion of the electrode. In some variations, the insulator may include a fluoropolymer material. In some variations, at least a portion of the distal surface of the electrode and the inner diameter of the electrode may not need to be insulated. In some variations, the electrode may be proximal to the dilator. In some variations, the first catheter may define a drainage lumen. In some variations, the signal generator may be configured to generate a two-phase waveform, and the signal generator may be coupled to the electrode.

[0009]

[0009] In some variations, the loop may define a longitudinal axis, and the loop may be configured to rotate about the longitudinal axis. In some variations, the loop may be configured to rotate up to about 360 degrees about the longitudinal axis.

[0010]

[0010] In some variations, the expander may define a recess configured to hold the return. In some variations, the return may be disposed inside the recess in a first configuration, and at least a portion of the return may be disposed outside the recess in a second configuration. In some variations, the length of the recess can be at least equal to the length of the return. In some variations, the return may be configured to translate relative to the expander to transition between the first configuration and the second configuration.

[0011]

[0011] In some variations, the expander may include a fluid port configured to discharge a contrast agent. In some variations, the proximal portion of the expander may include the fluid port. In some variations, the fluid port may be configured to receive the contrast agent from the lumen of the electrode. In some variations, the first catheter may include a lumen for the contrast agent. In some variations, the first catheter may be configured to discharge the contrast agent. In some variations, the contrast agent may be discharged into the lumen of the electrode. In some variations, the electrode may include a fluid port configured to discharge the contrast agent. In some variations, the distal end of the electrode may include the fluid port.

[0012]

[0012] In some variations, the expander may include an echo generating region. In some variations, the echo generating region may include one or more recesses or protrusions. In some variations, the one or more recesses or protrusions may include a diameter of about 5 μm to about 100 μm. In some variations, the echo generating region may include an uneven density of about 5% to about 50%. In some variations, the expander may include one or more microspheres. In some variations, the one or more microspheres may include a gas core. In some variations, the one or more microspheres may include glass. In some variations, the echo generating region may be on the surface of the expander. In some variations, the echo generating region may be below the surface of the expander.

[0013]

[0013] In some variations, the first catheter actuator may be configured to deflect the distal portion of the first catheter, and the first catheter actuator is electrically connected to the electrode. In some variations, the proximal end of the first catheter actuator may be configured to connect to an actuating mechanism. In some variations, the first catheter actuator may include a pull wire extending along the length of the first catheter. In some variations, the distal portion of the first catheter may include a predetermined bend. In some variations, the predetermined bend may include an angle of about 30 degrees to about 70 degrees.

[0014]

[0014] In some variations, the mating surface may define a recess configured to receive the distal end of the electrode. In some variations, the electrode may be configured to electrically short circuit when the electrode engages the recess of the mating surface. In some variations, the mating surface may include a deformable material. In some variations, the mating surface may include a non-conductive portion. In some variations, the non-conductive portion may include one or more of a polymer, a ceramic, and aluminum oxide. In some variations, the mating surface may include a conductive portion.

[0015]

[0015] In some variations, the proximal end of the dilator may be disposed within the lumen of the electrode when the mating surface engages the electrode. In some variations, about 0.5 mm to about 2 mm of the proximal portion of the dilator may be disposed within the lumen of the electrode when the mating surface engages the electrode.

[0016]

[0016] In some variations, the signal generator may be configured to generate a first waveform followed by a second waveform. The signal generator may be connected to the electrode. The first waveform may include a first voltage, and the second waveform may include a second voltage. The first voltage may be higher than the second voltage.

[0017]

[0017] This specification also describes a method. In some variations, a method of forming an anastomosis within the heart may include advancing a first and a second catheter into the right atrium. The first catheter may include a tubular electrode defining a lumen, and the second catheter may include a dilator and a snare. The second catheter may be advanced through the atrial septum into the left atrium such that the first catheter is within the right atrium. The second catheter may be retracted relative to the first catheter to engage the first portion of the septum with the snare, draw the first portion into the lumen, and compress the second portion of the septum between the electrode and the dilator. An ablation waveform may be delivered to the electrode to excise the second portion such that the first portion is retained within the lumen.

[0018]

[0018] In some variations, retracting the second catheter toward the first catheter may include retracting the snare into the lumen. In some of these variations, the size of the first portion excised from the second portion may correspond to the distance the snare is retracted into the lumen. In some variations, retracting the second catheter toward the first catheter may stretch the first portion. In some variations, the first portion may form a substantially conical or cylindrical shape when engaged by the snare.

[0019]

[0019] In some variations, the first portion of the septum can form a substantially cylindrical shape when drawn into the lumen. In some variations, the first portion of the septum engaged by the return can be intact when drawn into the lumen. In some variations, the return can puncture the first portion when drawing the second catheter into the first catheter. In some variations, an anastomosis having a diameter of about 1 mm to about 1.5 cm can be formed in response to delivering an ablation waveform. In some variations, the first portion can form a substantially conical shape when engaged by the return. In some variations, the first portion can be engaged by the return at least during delivery of the ablation waveform. In some variations, the first portion can be engaged by the return after delivering the ablation waveform to the electrode.

[0020]

[0020] In some variations, the second portion can be compressed with a force of at least 20 grams. In some variations, at least a portion of the return can penetrate the septum during engagement. In some variations, the electrode can be electrically shorted when the electrode contacts the dilator during delivery of the ablation waveform. In some variations, the ablation waveform can include a biphasic waveform. In some variations, one or more radiopaque portions of the first and second catheters can be imaged with a fluoroscope during one or more steps.

[0021]

[0021] In some variations, engaging the first portion of the septum with the return can include rotating the return about the longitudinal axis of the return. In some variations, the size of the first portion excised from the second portion can correspond to the rotation angle of the return. In some variations, rotating the return can include a rotation angle of up to about 360 degrees.

[0022]

[0022] In some variations, drawing the second catheter toward the first catheter can include translating the return relative to the dilator to engage the first portion of the septum.

[0023]

[0023] In some variations, retracting the second catheter toward the first catheter may include retracting the loop away from the expander.

[0024]

[0024] In some variations, retracting the second catheter toward the first catheter may include transitioning from a first configuration where the loop is disposed inside the recess of the expander to a second configuration where the loop is disposed outside the recess.

[0025]

[0025] In some variations, the contrast agent may be introduced into the heart through a fluid port in the expander. In some variations, the contrast agent may be introduced into the lumen of the electrode. In some variations, ultrasound may be received from the distal end of the ablation device. In some variations, the distal end of the ablation device may include one or more microspheres having a diameter of about 5 μm to about 100 μm.

[0026]

[0026] In some variations, retracting the second catheter toward the first catheter may deform the proximal portion of the expander. In some variations, retracting the second catheter toward the first catheter may include engaging the electrode with the mating surface of the second catheter. In some variations, compressing the second portion of the septum may include the distal end of the electrode and the mating surface of the expander. In some variations, the second portion may be compressed with a force of up to about 25 N.

[0027]

[0027] In some variations, the ablation waveform may include a first waveform followed by a second waveform. The first waveform may include a first voltage and the second waveform may include a second voltage. The first voltage may be higher than the second voltage.

[0028]

[0028] In some variations, the proximal portion of the dilator may include a first stepped portion having a first diameter and a second stepped portion having a second diameter greater than the first diameter. The first stepped portion may be proximal to the second stepped portion. In some variations, the second step may include a mating surface configured to engage the distal end of the electrode. In some variations, the mating surface may be substantially perpendicular to the longitudinal axis of the dilator. In some variations, the first step may be configured to engage the sidewall of the electrode when the dilator engages the electrode. In some variations, the dilator may be configured to be mounted to the first catheter when the dilator engages the electrode.

[0029]

[0029] In some variations, a system for forming an anastomosis within the heart may include a first catheter including an electrode and a second catheter slidably disposed within the first catheter. The second catheter may include a return and a dilator. The proximal portion of the dilator may include a first stepped portion having a first diameter and a second stepped portion having a second diameter greater than the first diameter. The first stepped portion may be proximal to the second stepped portion.

[0030]

[0030] In some variations, a system for forming an anastomosis within the heart may include a first catheter including an electrode and a second catheter slidably disposed within the first catheter. The second catheter may include a return and a dilator. The return may be received within the lumen of the electrode when the dilator engages the electrode.

[0031]

[0031] In some variations, a system for forming an anastomosis within the heart may include a first catheter including an electrode and a second catheter slidably disposed within the first catheter. The second catheter may include a return and a dilator. The system may be configured to compress the tissue between the electrode and the dilator with a first predetermined force.

[0032]

[0032] In some variations, the dilator may be configured to shear tissue with a second predetermined force greater than a first predetermined force. In some variations, the first predetermined force may be up to about 25 N. In some variations, the second predetermined force can be greater than about 25 N.

Brief Description of the Drawings

[0033]

Figure 1

[0033] Provide cross-sectional views of the heart showing various anatomical structures.

Figure 2A

[0034] It is a schematic perspective view of an exemplary variation of a method of forming an anastomosis using an ablation system.

Figure 2B

[0034] It is a schematic perspective view of an exemplary variation of a method of forming an anastomosis using an ablation system.

Figure 2C

[0034] It is a schematic perspective view of an exemplary variation of a method of forming an anastomosis using an ablation system.

Figure 2D

[0034] It is a schematic perspective view of an exemplary variation of a method of forming an anastomosis using an ablation system.

Figure 2E

[0034] It is a schematic perspective view of an exemplary variation of a method of forming an anastomosis using an ablation system.

Figure 2F

[0034] It is a schematic perspective view of an exemplary variation of a method of forming an anastomosis using an ablation system.

Figure 3

[0035] It is a schematic block diagram of an exemplary variation of an ablation system.

Figure 4

[0036] It is a perspective view of an exemplary variation of an ablation device.

Figure 5A

[0037] It is a schematic side cross-sectional view of an exemplary variation of an ablation device in an open configuration.

Figure 5B

[0037] It is a schematic side cross-sectional view of an exemplary variation of an ablation device in a closed configuration.

Figure 6A

[0038] Schematic side view of an exemplary variant of an ablation device in a closed configuration.

Figure 6B

[0038] Schematic side cross-sectional view of the ablation device shown in FIG. 6A.

Figure 6C

[0038] Detailed side cross-sectional view of the ablation device shown in FIG. 6B.

Figure 7A

[0039] Schematic side view of an exemplary variant of an ablation device in an open configuration.

Figure 7B

[0039] Schematic side cross-sectional view of the ablation device shown in FIG. 7A.

Figure 7C

[0039] Detailed side cross-sectional view of the ablation device shown in FIG. 7B.

Figure 8

[0040] Schematic perspective view of an exemplary variant of an ablation device.

Figure 9A

[0041] Schematic side view of an exemplary variant of an ablation device in a closed configuration.

Figure 9B

[0041] Schematic side cross-sectional view of an exemplary variant of an ablation device in a closed configuration.

Figure 10A

[0042] Schematic side view of an exemplary variant of an ablation device in an open configuration.

Figure 10B

[0042] Schematic side cross-sectional view of an exemplary variant of an ablation device in an open configuration.

Figure 11A

[0043] Schematic side cross-sectional view of an exemplary variant of an electrode of an ablation device.

Figure 11B

[0043] Detailed side cross-sectional view of the distal end of the electrode shown in FIG. 11A.

Figure 12A

[0044] Schematic perspective view of an exemplary variant of a connector of an ablation device.

Figure 12B

[0044] Schematic front view of an exemplary variant of a connector of an ablation device.

Figure 12C

[0044] Schematic side cross-sectional view of an exemplary variant of the connector of the ablation device.

Figure 13A

[0045] Schematic perspective view of an exemplary variant of the return of the ablation device.

Figure 13B

[0045] Schematic side view of an exemplary variant of the return of the ablation device.

Figure 13C

[0045] Schematic front view of an exemplary variant of the return of the ablation device.

Figure 14

[0046] Schematic side view of an exemplary variant of the return of the ablation device.

Figure 15A

[0047] Schematic perspective view of an exemplary variant of the return of the ablation device.

Figure 15B

[0047] Schematic front view of an exemplary variant of the return of the ablation device.

Figure 16

[0048] Schematic side view of an exemplary variant of the return of the ablation device.

Figure 17A

[0049] Schematic side view of an exemplary variant of the return of the ablation device.

Figure 17B

[0049] Schematic perspective view of an exemplary variant of the return of the ablation device.

Figure 18

[0050] Flowchart of an exemplary variant of the method of forming an anastomosis.

Figure 19A

[0051] Schematic perspective view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 19B

[0051] Schematic perspective view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 19C

[0051] Schematic side cross-sectional view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 19D

[0051] Schematic side cross-sectional view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 19E

[0051] This is a schematic side sectional view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 19F

[0051] This is a schematic side sectional view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 20

[0052] This is a perspective view of an exemplary variant of the ablation device.

Figure 21

[0053] This is a perspective view of an exemplary variant of the ablation device.

Figure 22

[0054] This is a perspective view of an exemplary variant of the ablation device engaged to excise tissue.

Figure 23

[0055] This is a visualization image by fluoroscope of an exemplary variant of the ablation device in open and closed configurations.

Figure 24

[0056] This is an image of an anastomosis formed within cadaveric tissue.

Figure 25A

[0057] This is an image of an anastomosis formed in porcine tissue.

Figure 25B

[0057] This is an image of an anastomosis formed in porcine tissue.

Figure 26A

[0058] This is a schematic side view of an exemplary variant of the return of the ablation device.

Figure 26B

[0058] This is a schematic perspective view of an exemplary variant of the return of the ablation device.

Figure 26C

[0058] This is a schematic front view of an exemplary variant of the return of the ablation device.

Figure 27A

[0059] This is a perspective view of an exemplary variant of the ablation device engaged to excise tissue.

Figure 27B

[0059] This is a perspective view of an exemplary variant of the ablation device engaged to excise tissue.

Figure 27C

[0059] This is an image of an anastomosis formed within tissue.

Figure 28A

[0060] Perspective view of an exemplary variant of an ablation device engaged for excising tissue.

Figure 28B

[0060] Perspective view of an exemplary variant of an ablation device engaged for excising tissue.

Figure 29A

[0061] Side view of the return of the ablation device within the pericardial cavity.

Figure 29B

[0061] Side view of the return of the ablation device within the pericardial cavity.

Figure 29C

[0061] Side view of the return of the ablation device within the pericardial cavity.

Figure 30A

[0062] Side cross-sectional view of the return of the ablation device and the catheter.

Figure 30B

[0062] Side cross-sectional view of the return of the ablation device and the catheter.

Figure 31A

[0063] Side view of an exemplary variant of the ablation device.

Figure 31B

[0063] Cross-sectional view of an exemplary variant of the ablation device.

Figure 31C

[0063] Detailed side cross-sectional view of the ablation device shown in Fig. 31B.

Figure 31D

[0063] Perspective view of an exemplary variant of the distal portion of the ablation device.

Figure 31E

[0063] Perspective view of an exemplary variant of the distal portion of the ablation device.

Figure 31F

[0063] Perspective view of an exemplary variant of the distal portion of the ablation device.

Figure 32

[0064] Side view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 33A

[0065] Side view of an exemplary variant of the catheter of the ablation device.

Figure 33B

[0065] Cross-sectional side view of an exemplary variant of the ablation device catheter.

Figure 34A

[0066] Cross-sectional plan view of the distal end of the ablation device catheter.

Figure 34B

[0066] Cross-sectional plan view of the distal end of the ablation device catheter.

Figure 34C

[0066] Cross-sectional side view of the ablation device catheter.

Figure 34D

[0066] Cross-sectional side view of the ablation device catheter.

Figure 35A

[0067] Cross-sectional side view of an exemplary variant of the distal portion of the ablation device.

Figure 35B

[0067] Detailed cross-sectional side view of another variant of the distal portion of the ablation device.

Figure 36A

[0068] Side view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 36B

[0068] Side view of an exemplary variant of the ablation device within the pericardial cavity.

Figure 37

[0069] Exemplary variant of the voltage waveform of the ablation procedure.

Figure 38A

[0070] Cross-sectional side view of an exemplary variant of the ablation device in the open configuration.

Figure 38B

[0070] Cross-sectional side view of an exemplary variant of the ablation device in the closed configuration.

Figure 39A

[0071] Perspective view of an exemplary variant of the handle of the ablation device.

Figure 39B

[0071] Plan view of the handle shown in FIG. 39A.

Figure 40A

[0072] Side view of an exemplary variant of the return of the ablation device.

Figure 40B

[0072] Perspective view of an exemplary variant of the return of the ablation device.

Figure 41A

[0073] Schematic side view of an exemplary variant of the return of the ablation device.

Figure 41B

[0073] Schematic perspective view of an exemplary variant of the return of the ablation device.

Figure 42A

[0074] Schematic side view of an exemplary variant of the electrode of the ablation device.

Figure 42B

[0074] Schematic perspective view of an exemplary variant of the electrode of the ablation device.

Mode for Carrying Out the Invention

[0034] Detailed Description

[0075] This specification describes an apparatus, system, and method for treating heart failure (e.g., congestive heart failure) by lowering the blood pressure within a patient's left atrium. For example, an energy-based tissue ablation system can be used to form an anastomosis between the right atrium and the left atrium to relieve the elevated left atrial pressure. Generally, the systems described herein can, for example, have a portion of the apparatus positioned on both sides of the atrial septum. A portion of the septum can engage the apparatus using a retractor. In some variations, a portion of the retractor can penetrate the septum, such that the retractor can securely hold an intact portion of the septal tissue. The engaged tissue can be stretched, fixed, and drawn into the lumen of the apparatus. In some variations, the size (e.g., diameter) of the tissue to be excised can be controlled by varying the distance that the engaged tissue is drawn into the lumen. Another portion of the septum can be compressed between the electrode and the proximal end of the dilator to fix another portion of the septum to the tissue. The electrode can excise tissue using radiofrequency (RF) energy to form an anastomosis within the atrial septum. After excision, the electrode can contact the dilator, and the portion of the tissue that engaged and was thereby held and / or fixed by the retractor remains housed within the lumen of the apparatus and is removed from the patient. One or more steps of the treatment can be visualized using one or more visualization techniques and visualization mechanisms incorporated within the ablation apparatus. Accordingly, the first and second catheters described herein can improve the efficiency and safety of the anastomosis formation procedure and miniaturize the catheter.

[0035]

[0076] When an organ related to the heart is involved, it may be beneficial to easily identify and describe the relevant cardiac anatomical structures. FIG. 1 is a cross-sectional view of a heart (100). Therein, a left atrium (110), a right atrium (120), and an atrial septum (130) are shown. FIG. 1 shows an opening (132) (e.g., a hole) formed between the left atrium (110) and the right atrium (120). For example, the opening (132) can be created during an anastomosis formation procedure using the systems, apparatuses, and methods described herein. The opening (132) can have predetermined characteristics configured to treat heart failure.

[0036]

[0077] This specification also describes a method. In some variations, the method of forming an anastomosis in the atrial septum may include the steps shown in FIG. 2A, which includes advancing an ablation device (200) into the patient's right atrium (230). The distal end of the device (200) may include an expander of a second catheter (250), which is configured to puncture the patient's atrial septum (210) and advance into the left atrium (220). In some variations, a guide wire (not shown) of the device (200) may be advanced across the atrial septum (210) and into the left atrium (220). As shown in FIG. 2B, the expander may puncture the septum (210), whereby a portion of the second catheter (250) is disposed within the left atrium (220) and the first catheter (240) is disposed within the right atrium (230).

[0037]

[0078] FIG. 2C shows that the second catheter (250) is advanced relative to the first catheter (240) such that the return (260) of the second catheter (250) crosses the septum (210) and is advanced into the left atrium (220). The return (260) may be configured to engage a portion of the septum for resection. For example, the engaged portion of the septum may be held and / or fixed between the protrusions of the return (260). By positioning the device (200) across both sides of the atrial septum (210), a predetermined force may be applied from each catheter (240, 250) to engage and resect a predetermined portion of the septal tissue.

[0038]

[0079] As shown in FIG. 2D, the second catheter (250) can be retracted relative to the first catheter (240), whereby a portion (212) of the septum (210) can engage the return (260) and stretch it. Each of the electrode (242) (FIG. 2A) and the return (260) can be positioned to engage each side of the septal tissue (212). For example, when the return (260) is drawn into the lumen of the electrode (242), it can engage the tissue (212) and stretch it to form a tent-like shape, which can assist in anastomosis formation. The tissue (212) in FIG. 2D is shown as being tent-shaped toward the right atrium (230). In this way, the tissue (212) to be excised prior to excision is fixed within the device (200), reducing the risk of uncontrolled tissue loss within the cardiac chamber and vascular structure.

[0039]

[0080] In some of these variations, the electrode (250) can include a tubular shape configured to excise tissue using RF energy and facilitate tissue capture. In some variations, the mating surface of the dilator (250) can be configured to engage the tissue to be excised, hold it, and fix it in a state of hitting the cutting surface of the electrode (242). The ablation waveform can be delivered to the electrode (242) to excise the portion (212) of the atrial septum (210) stretched by the device (200). For example, as described in more detail herein, the ablation waveform can include RF energy. The second catheter (250) can be positioned relative to the first catheter (240) such that when the electrode (242) is energized, the return (260) is held within the lumen of the electrode (242).

[0040]

[0081] When the septum (210) is excised, as shown in FIG. 2E, a hole (214) may be formed in the septum (210). The second catheter (250) may be withdrawn from the left atrium (220), and the device (210) may be removed from the patient as shown in FIG. 2F. Thus, the ablation device (200) may form an atrial anastomosis. The ablation device described herein may improve the efficiency and safety of the anastomosis formation procedure and enable miniaturization of the device. For example, after passing through the atrial septum (210), the operator may capture and fix tissue by advancing and retracting the second catheter (250) relative to the first catheter (240) without the need for other actuating mechanisms. This and other advantages of the device and method will be described in more detail later in this specification.

[0041] I. SYSTEM Overview

[0082] The system described herein may include one or more of the components used to excise tissue using the device described herein. FIG. 3 is a block diagram of one variation of an ablation system (300) that includes an ablation device (310), a handle (320), and a signal generator (330). In some variations, the ablation device (310) may be designed to be discarded after each use, and in other variations, one or more parts of the ablation device (310), such as the handle (320) and the signal generator (330), may be designed to be reusable (e.g., used multiple times for one or more patients).

[0042]

[0083] In some variations, the ablation device (310) may include first and second catheters sized and shaped to be placed within a body cavity such as a patient's heart chamber. In some variations, the ablation device (310) may include one or more of a guidewire (312), a dilator (314), a return (316), and an electrode (318). The distal end of the ablation device (310) may include a dilator (314), and the guidewire (312) may extend from the lumen of the dilator (314). In some variations, the electrode (318) may be disposed proximal to the return (316), and in other variations, the electrode (318) may be disposed distal to the return (318). Additionally or alternatively, the ablation system (300) may include a delivery catheter configured to be advanced around the ablation device (310). Further, the ablation device (310) may include one or more sensors configured to measure one or more predetermined characteristics such as temperature, pressure, impedance, and others.

[0043]

[0084] In some variations, the proximal end of the ablation device (310) may be coupled to a handle (320). The handle (320) may include an actuator (322) configured to control one or more of the movement, positioning, configuration, orientation, operation, and energy delivery of the ablation device (310). For example, the actuator (322) may be operated to guide and / or translate one or more portions of the ablation device (310). In some variations, a signal generator (330) may be coupled to one or more of the ablation device (310) and the handle (320). In some variations, the signal generator (330) may be configured to generate one or more ablation waveforms delivered to the electrode (318) of the ablation device (310). The signal generator (330) may include a controller (332) configured to control the signal generator (330), deliver an appropriate energy waveform for tissue ablation, and ensure patient safety.

[0044]

[0085] FIG. 4 is a perspective view of a variant of the ablation device (400). In some variants, the ablation device (400) may include a first catheter (410) and a second catheter (430). The first catheter (410) may include a tubular electrode (420). The electrode (420) may define a lumen (422) configured to hold one or more portions of the second catheter (430). The electrode (420) shown in FIG. 4 has a cylindrical shape. However, the electrode (420) may have any desired cross-sectional shape (e.g., oval, square, rectangular, triangular). The electrode (420) shown in FIG. 4 may include a distal cutting edge. However, the electrode (420) may also include angled or non-flat edges (e.g., corrugated, serrated, sawtooth, sinusoidal, periodic shapes, etc.).

[0045]

[0086] In some variations, the ablation device (400) can include a second catheter (430) slidably disposed within a first catheter (410). The second catheter (430) can include a return (440) and an expander (450) configured to engage an electrode (420). In some variations, the return (440) can be connected to the proximal portion of the expander (450). The tissue engaging portion (e.g., projection, tip) of the return (440) can generally face the electrode (420). The return (440) can include a plurality of projections. In some variations, one or more of the projections can be bent to form a curved shape. In some variations, the proximal portion of the expander (450) can be configured to contact the electrode (420) when the second catheter (430) is retracted relative to the first catheter (410). The expander (450) can have a generally conical shape that is tapered towards the distal end of the second catheter (430), for example. However, the expander (450) can include any given size, pattern, and shape. For example, at least a portion of the expander (450) can be retracted within the lumen (422) of the electrode (420) to secure the expander (450) to the catheter (410) during delivery and removal of the catheter and to further secure the excised tissue while being removed from the patient.

[0046]

[0087] As will be described in more detail herein, the second catheter (430) can be configured to translate relative to the first catheter (410). For example, the second catheter (430) can translate along the longitudinal axis of the first catheter (410). In some variations, one or more of the second catheter (430), the return (440), and the expander (450) can translate within the lumen (422) of the electrode (420). As will be described in more detail herein, the electrode (420) can be configured to excise tissue compressed between the distal end (e.g., distal side cutting edge, chamfer) of the electrode (420) and the expander (450).

[0047]

[0088] Figure 5A is a schematic side cross-sectional view of a variant of the ablation device (500) in an open configuration. In some variants, the ablation device (500) may include a first catheter (510) and a second catheter (530). The first catheter (510) may include a tubular electrode (520) and a connector (526) coupled to the electrode (520). The electrode (520) may define a lumen (522) configured to hold one or more portions of the second catheter (530). The first catheter (510) may further include a lead (524) coupled to the electrode (520) and a signal generator (not shown). In some variants, the first catheter (510) may include an insulator (560) configured to cover a portion of the electrode (520). For example, the insulator (560) may cover the outer surface of the electrode (520), and the distal end and the inner surface of the electrode (520) may be configured to be non-insulated.

[0048]

[0089] In some variations, the ablation device (500) may include a second catheter (530) slidably disposed within a first catheter (510). The second catheter (530) may include a return (540) and an expander (550) configured to engage an electrode (520). In some variations, the return (540) may generally include a plurality of protrusions angled and arranged toward the electrode (520). For example, the protrusions may be arranged along the length of the expander (550). Additionally or alternatively, one or more of the protrusions may be bent to form a curved shape. The expander (550) may be tapered and may define a lumen (552). The electrode (520) may be proximal to the expander (550). In some variations, the expander (550) may include a mating surface (554) configured to engage the electrode (520). For example, the electrode (520) and the mating surface (554) may be configured to compress tissue (not shown) therebetween. In some variations, the mating surface (554) may be non-perpendicular and non-parallel to the longitudinal axis of the second catheter (530) (e.g., chamfered, beveled). As shown in FIGS. 5A and 5B, the distal end of the electrode (520) and the mating surface (554) may be radial.

[0049]

[0090] Figure 5B is a schematic side cross-sectional view of a variant of the ablation device (500) in a closed configuration. The return (540) can be surrounded by the electrode (520), the connector (526), and the expander (550) in the closed configuration. That is, the return (540) can be disposed within the lumen (522) of the electrode (520) when the mating surface (554) engages the electrode (520). Thus, any tissue that the return (540) engages can be surrounded and fixed within the ablation device (500) in a closed configuration by one or more of the return (540) and the electrode (520). In some variants, the outer diameter of the expander (550) can be made smaller than the outer diameter of the distal end of the first catheter (510). For example, the outer diameter of the expander (550) can be made smaller than the outer diameter of the electrode (520). This can control the shape of the tent-like tissue that the ablation device (500) engages. As described in more detail herein, the length and shape of the return (540) can further control the size and shape of the tent-like tissue.

[0050]

[0091] Figure 6A is a schematic side view of a variant of the ablation device (600) in a closed configuration. Figure 6A shows an ablation device (600) including a first catheter (610), an electrode (620), an expander (650), and an insulator (660). Figure 6B is a schematic side cross-sectional view of the ablation device (600). In some variants, the ablation device (600) can include a first catheter (610) and a second catheter (630). The first catheter (610) can include a tubular electrode (620) and a connector (626) coupled to the electrode (620). The electrode (620) can define a lumen (622) configured to hold one or more portions of the second catheter (630). The first catheter (610) can further include a lead (624) coupled to the electrode (620) and a signal generator (not shown). In some variants, the first catheter (610) can include an insulator (660) configured to cover a portion of the electrode (620). For example, the insulator (660) can cover the outer surface of the electrode (620), and the distal end and the inner surface of the electrode (620) can be configured not to be insulated.

[0051]

[0092] In some variations, the ablation device (600) may include a second catheter (630) slidably disposed within a first catheter (610). The second catheter (630) may include a return (640) and an expander (650) configured to engage an electrode (620). In some variations, the return (640) may generally include a plurality of protrusions angled and arranged towards the electrode (620). For example, the protrusions may be arranged along the length of the expander (650). Additionally or alternatively, one or more of the protrusions may be bent to form a curved shape. The expander (650) may be tapered and may define a lumen (652). The electrode (620) may be proximal to the expander (650). Additionally or alternatively, one or more of the protrusions may be bent to form a curved shape.

[0052]

[0093] In the closed configuration, the return (640) may be surrounded by the electrode (620), the connector (626), and the expander (650). That is, the return (640) may be disposed within the lumen (622) of the electrode (620) when the mating surface (654) engages the electrode (620). Accordingly, any tissue that the return (640) engages may be surrounded, held, and / or fixed within the ablation device (600) in the closed configuration.

[0053]

[0094] Figure 6C is a detailed side cross-sectional view of the ablation device (600) shown in Figure 6B. Specifically, the expander (650) may include a mating surface (654) configured to engage the electrode (620). For example, the electrode (620) and the mating surface (654) may be configured to compress the tissue (not shown) therebetween. In some variations, the mating surface (654) may be non-perpendicular and non-parallel to the longitudinal axis of the second catheter (630) (e.g., be chamfered, be angled). The distal end of the electrode (620) and the mating surface (654) may be radial. As shown in Figures 6B and 6C, the outer diameter of the expander (650) can be made smaller than the outer diameter of the electrode (620).

[0054]

[0095] Figure 7A is a schematic side view of a variation of the ablation device (700) in an open configuration. Figure 7A shows an ablation device (700) including a first catheter (710), an electrode (720), a second catheter (730), a return (740), an expander (750), and an insulator (760). Figure 7B is a schematic side cross-sectional view of the ablation device (700) shown in Figure 7A. In some variations, the ablation device (700) may include a first catheter (710) and a second catheter (730). The first catheter (710) may include a tubular electrode (720) and a connector (726) connected to the electrode (720). The electrode (720) may define a lumen (722) configured to hold one or more portions of the second catheter (730). The first catheter (710) may further include a lead (724) connected to the electrode (720) and a signal generator (not shown). In some variations, the first catheter (710) may include an insulator (760) configured to cover a portion of the electrode (620). For example, the insulator (760) may cover the outer surface of the electrode (620), and the distal end and the inner surface of the electrode (720) may be configured not to be insulated.

[0055]

[0096] In some variations, the ablation device (700) may include a second catheter (730) slidably disposed within a first catheter (710). The second catheter (730) may include a return (740) and an expander (750) configured to engage an electrode (720). In some variations, the return (740) may generally include a plurality of protrusions angled and arranged toward the electrode (720). For example, the protrusions may be arranged along the length of the expander (750). Additionally or alternatively, one or more of the protrusions may be bent to form a curved shape. The expander (750) may be tapered and may define a lumen (752). The electrode (720) may be proximal to the expander (750).

[0056]

[0097] FIG. 7C is a detailed side cross-sectional view of the ablation device (700) shown in FIG. 7B. Specifically, the expander (750) may include a mating surface (754) configured to engage the electrode (720). For example, the electrode (720) and the mating surface (754) may be configured to compress tissue (not shown) therebetween. In some variations, the mating surface (754) may be non-perpendicular and non-parallel to the longitudinal axis of the second catheter (730) (e.g., chamfered, angled). The distal end of the electrode (720) and the mating surface (754) may be radial.

[0057]

[0098] FIGS. 8-10B show additional variations of the ablation device. FIG. 8 is a perspective view of a variation of the ablation device (800). In some variations, the ablation device (800) may include a first catheter (810) and a second catheter (830). The first catheter (810) may include a tubular electrode (820). The electrode (820) may define a lumen (822) configured to hold one or more portions of the second catheter (830). The electrode (820) shown in FIG. 8 has a cylindrical shape. However, the electrode (820) may include any desired cross-sectional shape (e.g., oval, square, rectangular, triangular).

[0058]

[0099] In some variations, the ablation device (800) can include a second catheter (830) slidably disposed within a first catheter (810). The second catheter (830) can include a return (840) and an expander (850) configured to engage an electrode (820). In some variations, the return (840) can be connected to the proximal portion of the expander (850). The return (840) can include a tapered portion and a plurality of protrusions radially disposed around the return (840) and staggered along the length of the second catheter (830). The tissue engaged by one or more of the protrusions can form a generally conical shape generally following the tapered shape of the return (840). The plurality of protrusions can have the same or different lengths, diameters, and tapers. Each row can have the same or different numbers of protrusions. The plurality of protrusions can have the same or different angles with respect to the second catheter (830).

[0059]

[0100] In some variations, the plurality of protrusions (e.g., tissue engagement portions) of the return (840) can be generally parallel to the longitudinal axis of the second catheter (830). In some variations, the proximal portion of the expander (850) can be configured to contact the electrode (820) when the second catheter (830) is retracted relative to the first catheter (810). The expander (850) can have a generally conical shape, for example, tapered towards the distal end of the second catheter (830). However, the expander (850) can have any given size, pattern, and shape.

[0060]

[0101] As will be described in more detail herein, the second catheter (830) can be configured to translate relative to the first catheter (810). For example, the second catheter (830) can translate along the longitudinal axis of the first catheter (810). In some variations, the second catheter (830), the return (840), and the dilator (850) can translate within the lumen (822) of the electrode (820). As will be described in more detail herein, the electrode (820) can be configured to excise tissue compressed between the distal end of the electrode (820) and the dilator (850).

[0061]

[0102] FIG. 9A is a schematic side view of a variation of an ablation device (900) in a closed configuration. FIG. 9A shows an ablation device (900) including a first catheter (910), an electrode (920), and a dilator (950). FIG. 9B is a schematic side cross-sectional view of the ablation device (900). In some variations, the ablation device (900) can include a first catheter (910) and a second catheter (930). The first catheter (910) can include a tubular electrode (920) and a connector (926) coupled to the electrode (920). The electrode (9620) can define a lumen (922) configured to hold one or more portions (e.g., the return (940)) of the second catheter (930). The first catheter (910) can further include a lead (not shown) coupled to the electrode (920) and a signal generator (not shown). In some variations, the first catheter (910) can include an insulator (960) configured to cover a portion of the electrode (920). For example, the insulator (960) can cover the outer surface of the electrode (920), and the distal end and the inner surface of the electrode (920) can be configured not to be insulated.

[0062]

[0103] In some variations, the ablation device (900) may include a second catheter (930) slidably disposed within a first catheter (910). The second catheter (930) may include a return (940) and an expander (950) configured to engage an electrode (920). In some variations, the return (940) may include a plurality of protrusions arranged generally parallel to the longitudinal axis of the second catheter (930). For example, the protrusions may be arranged along the length of the second catheter (930). Additionally or alternatively, one or more of the protrusions may be bent to form a curved shape. The expander (950) may be tapered and may define a lumen (952). In some variations, the expander (950) may include a mating surface (954) configured to engage the electrode (920). For example, the electrode (920) and the mating surface (954) may be configured to compress tissue (not shown) therebetween. In FIG. 9B, the mating surface (954) is generally perpendicular to the longitudinal axis of the second catheter (930). The electrode (920) may be proximal to the expander (950). The distal end of the electrode (920) and the mating surface (954) may be radial.

[0063]

[0104] In the closed configuration, the return (940) may be surrounded by the electrode (920), the connector (926), and the expander (950). That is, the return (940) may be disposed within the lumen (922) of the electrode (920) when the mating surface (954) of the expander (950) engages the electrode (920). Accordingly, tissue engaged with the return (940) may also be surrounded, held, and / or fixed within the ablation device (900) in the closed configuration.

[0064]

[0105] FIG. 10A is a schematic side view of a variant of an ablation device (1000) in an open configuration. FIG. 10A shows an ablation device (1000) including a first catheter (1010), an electrode (1020), a second catheter (1030), a return (1040), and an expander (1050). FIG. 10B is a schematic side cross-sectional view of the ablation device (1000) shown in FIG. 10A. In some variants, the ablation device (1000) may include a first catheter (1010) and a second catheter (1030). The first catheter (1010) may include a tubular electrode (1020) and a connector (1026) coupled to the electrode (1020). The electrode (1020) may define a lumen (1022) configured to hold one or more portions of the second catheter (1030). The first catheter (1010) may further include a lead (not shown) coupled to the electrode (1020) and a signal generator (not shown). In some variants, the first catheter (1010) may include an insulator (1060) configured to cover a portion of the electrode (1020). For example, the insulator (1060) may cover the outer surface of the electrode (1020), and the distal end and the inner surface of the electrode (1020) may be configured not to be insulated.

[0065]

[0106] In some variations, the ablation device (1000) can include a second catheter (1030) slidably disposed within a first catheter (1010). In some variations, the return (1040) can include a plurality of protrusions arranged generally parallel to the longitudinal axis of the second catheter (1030). For example, the protrusions can be arranged along the length of the second catheter (1030). Additionally or alternatively, one or more of the protrusions can be bent to form a curved shape. The dilator (1050) can be tapered and can define a lumen (1052). In some variations, the dilator (1050) can include a mating surface (1054) configured to engage an electrode (1020). For example, the electrode (1020) and the mating surface (1054) can be configured to compress tissue (not shown) therebetween. In FIG. 10B, the mating surface (1054) is generally perpendicular to the longitudinal axis of the second catheter (1030). The electrode (1020) can be proximal to the dilator (1050). The distal end of the electrode (1020) and the mating surface (1054) can be radial.

[0066]

[0107] Figure 38A is a schematic side cross-sectional view of a variant of the ablation device (3800) in a closed configuration. In some variants, the ablation device (3800) may include a first catheter (3810) and a second catheter (3830). The first catheter (3810) may include an electrode (3820), such as a tubular electrode. The electrode (3820) may define a lumen configured to hold one or more portions of the second catheter (3830). The first catheter (3810) may further include a first catheter actuator (3822) (e.g., a lead, an electrical pull wire) coupled to the electrode (3820) and a signal generator (not shown). As will be described in more detail herein, the first catheter actuator (3822) may be configured to deliver electrical energy to the electrode (3820) and deflect the distal portion of the ablation device (3800) like a pull wire. In some variants, the first catheter (3810) may include an insulator (3824) configured to cover a portion of the electrode (3820). For example, the insulator (3824) may cover the outer surface of the electrode (3820) and be configured such that the distal end and the inner surface of the electrode (3820) are not insulated. In some variants, the first catheter (3810) may include a contrast agent lumen (3812), as will be described in more detail herein.

[0067]

[0108] In some variants, the ablation device (3800) may include a second catheter (3830) slidably disposed within the first catheter (3810). The second catheter (3830) may include a return (3840) and an expander (3850) configured to engage the electrode (3820). In some variants, the return (3840) may include a plurality of protrusions (3842, 3844) radially disposed and generally extending toward the electrode (3820). For example, the protrusions (3842, 3844) may include a distal portion (3842) configured to puncture tissue and a proximal portion (3844) configured as a backstop against the tissue.

[0068]

[0109] In some variations, the dilator (3850) may be tapered and define a lumen (3852). In some variations, a guide wire (not shown) may be slidably disposed within the lumen (3852). In some variations, the dilator (3850) may include a proximal portion (3854) and an echo generating region (not shown). For example, the echo generating region may include a predetermined surface texture configured for visualization using ultrasonic imaging. The proximal portion (3854) of the dilator (3850) may be configured to engage the electrode (3820) in a closed configuration. That is, the proximal portion (3854) may be configured to be within the lumen of the electrode (3820) in the closed configuration of the ablation device (3800). In some variations, the dilator (3850) may include a mating surface (3856) configured to engage the electrode (3820). For example, the electrode (3820) and the mating surface (3856) may be configured to compress tissue (not shown) therebetween, as described in more detail with respect to FIG. 36A. The mating surface (3856) of the dilator (3850) may extend radially and / or longitudinally.

[0069]

[0110] In a closed configuration, the return (3840) can be surrounded by the first catheter (3810), the electrode (3820), and the expander (3850). That is, the return (3840) can be disposed within the lumen of the electrode (3820) when the proximal portion (3854) (e.g., mating surface (3856)) engages (e.g., seats therein) with the electrode (3820). Thus, the tissue engaged with the return (3840) can also be surrounded and fixed within the ablation device (3800) of the closed configuration by the return (3840) and the electrode (3820). The proximal portion (3854) disposed within the lumen of the electrode (3820) can be securely coaxially attached to the electrode (3820) and the expander (3850). For example, the expander (3850) can be fixed to the first catheter (3810) to withstand movement due to lateral loads, such as when the ablation device (3800) is advanced following a curved guide wire. Further, the electrode (3820) securely engaged with the expander (3850) can be configured to prevent the ablation device (3800) from catching (e.g., hitting) on blood vessels, tissue (e.g., septal crossing), introducers, sheaths, and others while being advanced and retracted within the body cavity. In some variations, when the mating surface engages with the electrode (3820), about 0.5 mm to about 2 mm of the proximal portion (3854) of the expander (3850) can be disposed within the lumen of the electrode (3820).

[0070]

[0111] FIG. 38B is a schematic side view of a variant of the ablation device (3800) in an open configuration. The second catheter (3830) can be configured to translate relative to the first catheter (3810) via an actuator mechanism of the handle as described herein with respect to FIGS. 39A and 39B. FIG. 36A shows the ablation device (3600) in an excision configuration between the open configuration and the closed configuration. The ablation device (3600) can correspond to the ablation device (3800).

[0071]

[0112] In some variations, the proximal portion (3854) of the dilator (3850) may include a first stepped portion having a first diameter and a second stepped portion having a second diameter larger than the first diameter. The first stepped portion may be proximal to the second stepped portion. In some variations, the second step may include a mating surface (3856) configured to engage the distal end of the electrode (3820). In some variations, the mating surface (3856) may be substantially perpendicular to the longitudinal axis of the dilator (3850). In some variations, the first step may be configured to engage the sidewall of the electrode (3820) when the dilator (3850) engages the electrode (3820). In some variations, the dilator (3850) may be configured to attach to the first catheter (3810) when the dilator (3850) engages the electrode (3820).

[0072] Electrode

[0113] Generally, the electrodes described herein may be configured to excise tissue, such as a portion of the patient's atrial septum, to reduce the blood pressure within the patient's left atrium. In some variations, the electrode may engage the septum and be energized to excise a portion of the septal tissue to form a predetermined opening between the left atrium and the right atrium. For example, the tissue may be heated using radiofrequency (RF) energy during electro-surgery. RF energy tissue ablation may be used to rapidly and accurately excise tissue without causing significant damage to surrounding tissue. In some variations, the RF energy may be delivered to the tissue by the electrode to rapidly and accurately excise the tissue to form an anastomosis of a predetermined shape and size.

[0073]

[0114] In some variations, the tissue resection characteristics can be controlled by the size, shape, and / or arrangement of the conductive region of the electrode. For example, the electrode can include a thin radial edge configured to apply high-density energy to a small contact surface area of the tissue to be resected. This can rapidly resect tissue with less energy than an electrode having a larger contact surface area. In some variations, the distal end of the electrode is angled (e.g., chamfered, beveled) with respect to the longitudinal axis of the electrode, which can further reduce the contact surface area of the electrode with the tissue. In some variations, the width of the chamfered surface can be from about 0.025 mm to about 0.040 mm, including all ranges and sub-values therebetween. For example, the width of the chamfered surface can be from about 0.05 mm to about 0.08 mm.

[0074]

[0115] Furthermore, the small contact surface area of the electrode can assist in compressing the tissue prior to resection. For example, as shown in FIGS. 6A-6C and FIGS. 9A-9B, the distal end of the electrode (620, 920) can be configured to abut against the corresponding mating surface (654, 954). When the contact surface area of the electrode is smaller, the compressive force applied to the tissue hitting the mating surface can be higher. Compression of the tissue between the electrode and the mating surface can provide various advantages. For example, by thinning the thickness of the tissue resected by compression, it may be possible to more rapidly resect the septum with less energy. Furthermore, compression of the tissue can hold (e.g., fix, lock) the tissue in a predetermined position relative to the ablation device, thereby ensuring that only a predetermined portion of the tissue is resected. In some variations, by compressing the tissue during operation, layers of the tissue (e.g., the left and right atrial septal layers) can fuse during resection, thereby reducing the surface area of the tissue exposed along the perimeter of the anastomosis after tissue resection. In some variations, compression of the tissue can be used to reduce the volume of the tissue, thereby allowing a larger volume of tissue to be accommodated within the lumen of the electrode after resection, and as a result, a relatively large anastomosis can be formed.

[0075]

[0116] In some variations, the shape of the opening in the atrial septum can be based on the shape of the electrode. For example, the electrodes (420, 820) of FIGS. 4 and 8, respectively, can have a tubular shape, which can generally be used to create a circular opening. In some variations, at least a portion of the distal end of the electrode can be angled at about 5 degrees to about 75 degrees with respect to the longitudinal axis of the electrode, such that a chamfer and / or bevel can be formed. For example, at least a portion of the distal end of the electrode can be angled at about 30 degrees to about 60 degrees with respect to the longitudinal axis of the electrode. For example, the distal ends (628, 728) of the electrodes (620, 720) of FIGS. 6C and 7C, respectively, can be radially angled at about 45 degrees with respect to the longitudinal axis of the electrodes (620, 720).

[0076]

[0117] As described herein, chamfered electrodes can reduce the contact surface area of the electrodes and can apply a large compressive force to the tissue. In some variations, the corresponding mating surfaces of the dilator can also be chamfered to facilitate aligning and connecting the dilator with the electrode when pulling the dilator into the electrode. In some variations, at least a portion of the mating surface of the dilator can be angled at about 5 degrees to about 75 degrees with respect to the longitudinal axis of the dilator. For example, at least a portion of the mating surface of the dilator can be angled at about 30 degrees to about 60 degrees with respect to the longitudinal axis of the dilator. In this way, the chamfered electrodes provide a tolerance for misalignment between the electrode and the dilator, for example, due to tissue sandwiched therebetween, such that the dilator can be seated within the electrode.

[0077]

[0118] In some variations, one or more portions of the electrode may be coated with an insulator (e.g., PTFE, ePTFE, PET, polyolefin, parylene, FEP, silicone, nylon, PEEK, polyimide) so that the contact surface area of the electrode can be reduced. By making the surface area relatively small, the formation of bubbles, as well as char formation and electrode operating time, can be reduced. In some variations, the inner surface of the electrode remains uninsulated and can serve as a conductive path through which current flows through the contained tissue during and after tissue resection. In some variations, due to conduction through the tissue, the volume of the resected tissue can be reduced by drying and / or denaturing of the protein, and as a result, a larger volume of tissue can be accommodated.

[0078]

[0119] FIGS. 11A and 11B are schematic side cross-sectional views of an electrode (1110) of an ablation device (1100). Specifically, the distal end of the first catheter may include an electrode (1110) having a distal end (1120), an insulator (1130), a lead (1140), and a connector (1150). The electrode (1110) may include a distal end (1120) and have a tubular shape defining a lumen (1112). In some variations, the lumen (1112) may be configured to surround one or more of the returned tissue and the proximal portion of the dilator engaged therewith. FIG. 5A is a cross-sectional perspective view of the lumen (522), and FIG. 5B shows a portion of the return (540) and dilator (550) disposed within the lumen (522). Further, as shown in FIG. 22, the lumen (2222) may have a volume sufficient to surround a predetermined volume of tissue (2260). Similarly, FIGS. 27A and 27B are images including a predetermined volume of tissue (2760) that fits within the lumen of the electrode (2720). As another example, the tissue (2860) shown in FIGS. 28A and 28B may be configured to fit within the lumen of an electrode (not shown). In some variations, the lumen may have a length of at least 1 mm. For example, the lumen may have a length of about 5 mm to about 4 cm.

[0079]

[0120] In some deformation modes, the connector (1150) can be connected to each of the electrode (1110) and the lead (1140). The insulator (1130) can be configured to cover one or more outer surfaces of the electrode (1110) and the connector (1150). In some deformation modes, the inner surface of the electrode (1110) can be left non-insulated. In some deformation modes, up to about 2 mm of the outer surface of the electrode can be left non-insulated. For example, up to about 0.15 mm of the outer surface of the electrode can be left non-insulated.

[0080]

[0121] As shown in the detailed side cross-sectional view of FIG. 11B, the distal end (1120) of the electrode (1110) can be angled (e.g., chamfered, beveled) with respect to the longitudinal axis of the electrode (1110). In some deformation modes, the chamfer can extend radially along the distal end (1120). The distal end (1120) can have a single angle or multiple angles. For example, the surface of the distal end (1120) can have a sinusoidal shape, in which case the corresponding mating surface of the expander can have a corresponding sinusoidal shape. Thereby, the respective mating surfaces of the electrode and the expander can contact each other in a predetermined orientation and can be compressed.

[0081]

[0122] In some deformation modes, the electrode can include one or more biocompatible metals, such as titanium, stainless steel, nitinol, palladium, silver, platinum, combinations thereof, and others. In some deformation modes, the electrode can include a non-traumatic (e.g., non-pointed, rounded) distal edge so that the electrode does not pierce tissue when pressed against an opposing surface such as the mating surface of the expander. For example, the electrode can engage the tissue along its chamfered circumferential edge and compress it.

[0082]

[0123] In some deformation modes, the diameter of the excised tissue can be from about 1 mm to about 1.5 cm, including all ranges and fractional values therebetween. For example, the diameter of the tissue to be excised can be from about 0.5 mm to about 12 mm. For example, the diameter of the tissue to be excised can be from about 6 mm to about 9 mm.

[0083]

[0124] In some variations, heating of the tissue can reduce the tissue prior to excision. In some variations, heating of the tissue can reduce the tissue after excision. In some variations, the tissue can be heated to a predetermined temperature range. In some variations, the tissue to be excised can be heated to at least about 60°C, about 70°C, about 80°C, about 90°C, and about 100°C for a predetermined length of time. In some variations, the tissue to be excised can be heated from about 50°C to about 100°C for a predetermined length of time. In some variations, only the tissue to be excised can be heated, and in other variations, only a portion of the tissue to be excised can be heated. In some variations, the electrode can be configured to rotate, vibrate, and / or oscillate during and after energy delivery to prevent, reduce, and / or disrupt char formation.

[0084]

[0125] In some variations, the electrode can be connected to a signal generator by a lead (e.g., a conductive wire). The lead can extend from the proximal portion of the first catheter to the electrode at the distal portion of the first catheter. One or more portions of the lead can be insulated. The lead is configured to maintain a predetermined voltage potential without causing dielectric breakdown of the corresponding insulation.

[0085]

[0126] Figures 12A and 12B are a perspective view and a front view, respectively, of a connector (1200) of an ablation device. Figure 12C is a side cross-sectional view of the connector (1200). In some variations, the connector (1200) can be configured to couple an electrode and a lead to a shaft of a first catheter (not shown for clarity). The connector (1200) can include a lumen (1210) configured to slidably dispose a second catheter and a channel (1220) configured for a distal end of the lead. In some variations, at least a portion of an inner surface of the connector (1200) can be made slippery to facilitate translational movement of the second catheter relative to the connector (1200). For example, the inner surface of the connector (1200) can include a layer of PTFE to facilitate translational movement and / or rotation of a second catheter slidably disposed within the lumen (1210) for lubrication. In some variations, the connector (1200) can include a vent lumen (not shown) configured to discharge fluid (e.g., air, heat, liquid) from a lumen of the electrode to a lumen of the first catheter.

[0086]

[0127] In some variations, the connector (1200) can include a length of at least about 0.1 mm. For example, the connector (1200) can include a length of about 1 mm to about 2 cm and about 2 mm to about 7 mm. In some variations, the lumen (1210) can include a length of at least 0.1 mm. For example, the lumen (1210) can include a length of about 1 mm to about 1 cm. In some variations, the channel (1220) can include a length of at least 0.1 mm. For example, the channel (1220) can include a length of about 1 mm to about 5 mm.

[0087]

[0128] In some variations, the systems disclosed herein may include a return electrode (e.g., an RF energy sink) for extracting RF energy from a patient. In some variations, the second catheter may include the return electrode. In some variations, the return electrode may be external to and in contact with the return electrode (e.g., a skin patch electrode, a ground pad). For example, a set of return electrodes may be placed on a patient's back to allow current to pass through the patient's body from the electrodes and then through the return electrodes. For example, one or more return electrodes may be placed on the patient's skin. A conductive gel may be applied between the return electrode and the skin to improve contact.

[0088] Insulator

[0129] Generally, the insulators described herein may be configured to electrically insulate one or more portions of the ablation device's electrodes and / or catheters. In some variations, the insulator may include one or more of poly(p-xylylene) polymers (e.g., parylene C, parylene N), polyurethane (PU), polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE), polyimide (PI), polyester, polyethylene terephthalate (PET), PEEK, polyolefin, silicone, copolymers, ceramics, combinations thereof, and others.

[0089] Return

[0130] Generally, the retractor described herein can be configured to engage tissue such as the atrial septum of a patient to control the size and shape of the septal tissue to be resected. In some variations, a portion of the septal tissue can engage one or more protrusions of the retractor and be stretched across the one or more protrusions to hold the tissue in place before and after tissue resection. In some variations, the protrusions can be configured to penetrate or pierce the tissue by a predetermined distance. For example, the protrusions can be configured to penetrate through multiple layers of the atrial septum (e.g., one or more left atrial layers and right atrial layers) to fix the septal tissue to the retractor while, on the other hand, maintaining the structural integrity of the entire septum. In some of these variations, by the protrusions penetrating the tissue, the tissue can be held to the retractor, reducing the shear strain of the tissue when drawn into the electrode and improving the consistency and shape (e.g., cylindricity) of the resection. That is, the retractor can be configured to capture the tissue without tearing it, such that the tissue can be held in a state engaged with the retractor during electro-surgery.

[0090]

[0131] For example, the retractor can be configured to prevent tearing by dispersing the pressure when the tissue engages and is pulled. For example, the engaged tissue can generally form a conical tent-like shape around the retractor and apply tension to the septum. In some variations, the retractor can be configured to provide a counter-tension to the atrial septum during energization of the electrode to minimize unintended tissue deformation, rotation, and displacement due to unbalanced forces (e.g., tissue movement due to heartbeat). The engaged tissue and the retractor can be drawn into the lumen of the ablation device to hold and fix the tissue during tissue resection. In some variations, the size of the anastomosis can depend on the distance the retractor is drawn into the electrode and can be independent of the diameter of the ablation device. Thereby, the ablation device can have an electrode of a fixed diameter and be capable of forming an anastomosis with a diameter larger than that of the electrode. The size (e.g., diameter, length) and shape of the retractor should be such that it can fit into the lumen of the electrode while it is engaged with the tissue. In some variations, the diameter of the tissue opening can be calculated using Equation (1).

Number

[0091]

[0132] FIGS. 13A - 13C are various views of the return (1300) of the ablation device. The return (1300) can include one or more protrusions (1320) (e.g., prongs) having a proximal end that includes a base portion (1310) and a tissue engagement portion (1322) (e.g., a tip). The base portion (1310) is generally cylindrical and can be configured to be coupled to the expander and the proximal portion of the shaft of a second catheter (not shown). For example, the base portion (1310) can be on the proximal side of the expander of the second catheter.

[0092]

[0133] One or more of the protrusions (1320) can be coupled to the proximal end of the base portion (1310). In some variations, the protrusions (1320) can include elongate elements. For example, the return (1300) can include at least one protrusion (1320). In some variations, the protrusions (1320) can be spaced substantially equidistantly along the circumference of the base portion (1310). In some variations, each of the protrusions (1320) can have the same or different lengths. In some variations, the length of the return (1300) can be from about 0.1 mm to about 5 cm. In some variations, one or more of the protrusions (1320) can be linear, curved, curvilinear, rounded, arcuate, and others.

[0093]

[0134] In some variations, the projection (1320) may include one or more tissue engagement portions (1322). The tissue engagement portion (1322) and / or the projection (1320) may be configured to engage the tissue without tearing the tissue on the other hand and preventing loss of tissue integrity. In some variations, the tissue engagement portion (1322) may be configured to pierce or penetrate the tissue. In some variations, the shape and size of each tissue engagement portion (1322) may be the same or different. For example, the tissue engagement portion (1322) may include a sharp tip or a non-traumatic end that is not sharp. In some variations, the tissue engagement portion (1322) may include one or more secondary structures (e.g., serrations) to prevent the tissue from slipping off the projection (1320). In some variations, the tissue engagement portion (1322) may include an angle of about 10 degrees to about 90 degrees with respect to the longitudinal axis of the projection (1320). In some variations, the length of the projection (1320) and / or the tissue engagement portion (1322) may be from about 0.1 mm to about 2 cm.

[0094]

[0135] In some variations, the projection (1320) is generally linear but may be angled with respect to the longitudinal axis of the base (1310). For example, the projection (1320) may be configured to flare outwardly to capture and engage the tissue. In some variations, the projection may include one or more curved or angled portions. In some variations, the tissue may be configured to engage one or more portions of the projection (1320). In some variations, the return projection may be angled from about 5 degrees to about 60 degrees with respect to the longitudinal axis of the base (1310), including all values and sub-ranges therebetween. For example, the projection (1320) may include an angle of about 30 degrees to about 45 degrees. Each projection (1320) may have the same or different angles with respect to the longitudinal axis.

[0095]

[0136] In some variations, the protrusion (1320) can be configured to engage a predetermined length and / or volume of tissue. For example, the protrusion (1320) can include a proximal portion configured as a barrier (e.g., a backstop, a wall) to engagement (e.g., advancement, penetration) of tissue beyond it, thereby reducing tearing of the tissue.

[0096]

[0137] FIG. 14 is a schematic side view of a return (1400) of an ablation device. The return (1400) can include one or more protrusions (1420) having a proximal end that includes a base portion (1410) and a tissue engagement portion (1422). The protrusions (1420) of the return (1400) can be angled in a manner similar to the returns (1300) of FIGS. 13A - 13C. In some variations, the return can include from about two protrusions to about twelve protrusions, including all values and sub - ranges therebetween. For example, the return can include from about five protrusions to about seven protrusions.

[0097]

[0138] FIG. 15A is a schematic side view of a return (1500) of an ablation device. FIG. 15B is a front view of the return (1500). The return (1500) can include one or more protrusions (1520, 1530) each having a proximal end that includes a respective base portion (1510) and a respective tissue engagement portion (1522, 1532). In some variations, one or more of the protrusions (1520, 1530) can be configured to be arranged along the length of the return (1500). For example, the return (1500) can include one or more arranged protrusions (1520, 1530). In some variations, the rows of protrusions (1520, 1530) can be staggered as shown in FIGS. 15A and 15B. The tissue engaging the return (1500) can generally form a conical tent - like shape.

[0098]

[0139] Figure 16 is a schematic side view of the return (1600) of the ablation device. The return (1600) can include one or more protrusions (1620) having a proximal end that includes a base (1610) and a tissue engagement portion (1622). The protrusions (1620) can be parallel to the longitudinal axis of the base (1610). Figures 17A and 17B are a schematic side view and a perspective view, respectively, of the return (1700) of the ablation device. The return (1700) can include one or more protrusions (1720) having a proximal end that includes a base (1710) and a tissue engagement portion (1722). The tissue engagement portion (1722) can extend along a majority of the length of the protrusion (1720). In some variations, the base (1610) can have a diameter that is smaller than the diameter of the electrode. In some variations, the protrusions (1620, 1720) and the tissue engagement portions (1622, 1722) can include a length configured to penetrate the atrial septum. One or more tissue engagement portions (1722) can include a length that, as shown in Figures 17A and 17B, can assist in piercing and / or penetrating tissue with less force due to a greater taper.

[0099]

[0140] Figures 41A and 41B are a schematic side view and a perspective view, respectively, of the return (4100) of the ablation device. The return (4100) can include one or more protrusions (4120) having a proximal end that includes a base (4110) and a tissue engagement portion (4122). In some variations, the protrusions (4120) and the tissue engagement portions (4122) can include a length configured to penetrate the atrial septum. One or more tissue engagement portions (4122) can include a length that can assist in piercing and / or penetrating tissue, as shown in Figures 41A and 41B.

[0100]

[0141] Figures 26A - 26C show various views of the return (2600) of the ablation device. The return (2600) may include a base (2610) and one or more protrusions (2620) (e.g., prongs, tines). The protrusion (2620) may include a first portion (2624) and a distal portion (e.g., a tissue engagement portion (2622) (e.g., a tip, a chip)). In some variations, the first portion (2624) may be angled with respect to the second portion (2622). For example, the protrusion (2620) may include a bend where the first portion (2624) is substantially perpendicular to the second portion (2622). The base (2610) is generally cylindrical and may be configured to be coupled to the proximal portion of the dilator and shaft of a second catheter (not shown). For example, the base (2610) may be on the proximal side of the dilator of the second catheter.

[0101]

[0142] One or more of the protrusions (2620) may be coupled to the end of the base (2610). In some variations, the protrusion (2620) may include an elongate element. For example, the return (2600) may include at least one protrusion (2620). In some variations, the protrusions (2620) may be substantially equally spaced along the circumference of the base (2610) and may extend from the longitudinal axis of the base (2610). In some variations, each of the protrusions (2620) may have the same or different lengths. In some variations, the length of the return (2600) may be from about 0.1 mm to about 5 cm. In some variations, the ratio of the length of the proximal portion to the length of the distal portion may be from about 2:3 to about 1:5. In some variations, one or more of the protrusions (2620) may be linear, curved, curvilinear, rounded, arcuate, and the like. For example, the protrusion (2610) may be "L"-shaped, "J"-shaped, or "C"-shaped, and the protrusions (2610) may collectively define a diameter larger than the diameter of the base (2610).

[0102]

[0143] In some variations, the distal portion (2620) of the protrusion (2620) may include one or more tissue engagement portions (2622). The tissue engagement portion (2622) and / or the protrusion (2620) may be configured to prevent loss of tissue integrity while engaging the tissue without tearing the tissue. In some variations, the tissue engagement portion (2622) may be configured to pierce or penetrate the tissue. In some variations, the shape and size of each tissue engagement portion (2622) may be the same or different. For example, the tissue engagement portion (2622) may include a sharp tip or a non-traumatic end that is not sharp. In some variations, the tissue engagement portion (2622) may include one or more secondary structures (e.g., serrations) to prevent the tissue from slipping off the protrusion (2620). In some variations, the tissue engagement portion (2622) may be substantially parallel to the longitudinal axis of the base portion (2620). In some variations, the length of the protrusion (2620) may be from about 0.1 mm to about 2 cm. For example, the protrusion (2620) may include lengths of about 1.25 mm to about 1.75 mm and about 1.5 mm. In some variations, the length of the tissue engagement portion (2622) may be from about 1.0 mm to about 1.5 mm, including all ranges and sub-values therebetween.

[0103]

[0144] In some variations, the protrusion (2620) may generally be linear, but may include one or more bends. For example, the first portion (2624) of the protrusion (2620) may be configured to extend substantially perpendicular to the longitudinal axis of the base portion (2620). In some variations, the protrusion may include one or more curved or angled portions between the first portion (2624) and the second portion (2622). In some variations, the tissue may be configured to engage one or more portions of the protrusion (2620).

[0104]

[0145] In some variations, the first portion (2624) of the protrusion (2622) can be angled from about 60 degrees to about 120 degrees relative to the longitudinal axis of the base (2610), including all values and sub - ranges therebetween. For example, the protrusion (2620) can include an angle from about 80 degrees to about 100 degrees relative to the longitudinal axis of the base (2610). As shown in FIG. 26A, the first portion (2624) can be substantially perpendicular to the longitudinal axis of the base (2610). The first portions (2624) of the protrusions (2620) can have the same or different angles relative to the longitudinal axis, respectively. In some variations, the second portion (2622) of the protrusion (2620) can be angled up to about 30 degrees relative to the longitudinal axis of the base (2610). For example, as shown in FIG. 26A, the second portion (2622) can be substantially parallel to the longitudinal axis of the base (2610).

[0105]

[0146] In some variations, the protrusion (2620) can be configured to engage tissue of a predetermined length and / or volume. For example, the second portion (2622) can engage and pierce the tissue, and the first portion (2624) can engage the tissue and secure it to the clip (2600). The second portion (2622) can be configured to pierce the tissue such that layers of the atrial septum (e.g., left and right atrial layers) are held together, reducing tissue separation and / or tissue shearing. For example, the protrusion (2620) can be configured to bite into various layers of the septum, hold them together, and reduce relative shearing of the septal tissue layers during translational movement, thereby reducing beveling of the resulting anastomosis. The first portion (2624) can be further configured as a barrier (e.g., a backstop, a wall) against engaging the tissue beyond it (e.g., advancing, penetrating), thereby reducing tissue tearing. A predetermined volume of tissue can be captured by the protrusion (2620) when the clip is drawn into the lumen of the electrode.

[0106]

[0147] In some variations, the retriever can include from about 3 to about 12 protrusions, including all values and sub-ranges therebetween. For example, the retriever can include from about 3 to about 7 protrusions. In some variations, the plurality of tissue engagement portions (2622) can extend from the same first portion (2624), which can collectively include, for example, a series of concentric rings. In some variations, a series of protrusions can be staggered. The tissue engaging the retriever (2600) can generally form a conical or cylindrical tent-like shape. In some variations, the tissue engagement portion (2622) can extend along a majority of the length of the protrusion (2620). In some variations, the base (2610) can have a diameter smaller than the diameter of the electrode.

[0107]

[0148] In some variations, the retriever can be configured to transition from a compressed configuration to an expanded configuration. For example, the retriever can be in a compressed configuration when disposed within the lumen of the electrode. The retriever can transition to an expanded configuration when a second catheter is advanced relative to the first catheter such that the retriever is advanced out of the lumen of the electrode, thereby enabling the retriever to engage a larger volume of tissue.

[0108]

[0149] In some variations, the retriever can be configured to engage tissue for excision by rotating the retriever (2920) by a predetermined angle. FIGS. 29A, 29B, and 29C are side views of the retriever (2920) of an ablation device (2900) within a pericardial cavity. The ablation device (2900) can include a catheter (2910) (e.g., distal tip, dilator) and a retriever (2920). The retriever (2920) can include one or more protrusions (e.g., prongs, tines) including a base (2926) and a second portion (e.g., tissue engagement portion) (2922) (e.g., tip, apex) and a first portion (2924).

[0109]

[0150] In some variations, the second portion (2922) (e.g., the tissue engagement portion) can be configured to engage the tissue (2930) without tearing the tissue while preventing loss of tissue integrity on the other hand. In some variations, the second portion (2922) can be configured to pierce or penetrate the tissue. FIG. 29A depicts the initial penetration of the tissue (2930) by the second portion (2922). When the retriever (2920) is advanced toward the tissue (2930), in FIG. 29B, the second portion (2922) is shown to penetrate through the entire thickness of the tissue (2930) (e.g., the atrial septum).

[0110]

[0151] In some variations, the size (e.g., diameter) of the tissue (2930) to be excised can be controlled by rotating (e.g., twisting) the retriever (2920) about the longitudinal axis (2921) of its base (2926). For example, by rotating the retriever (2920) after engaging the tissue (2930) (FIG. 29B), the amount of tissue (2930) engaged with the retriever (2920) for excision can be increased. When the retriever is rotated, the tissue (2930) is drawn (e.g., compressed) toward the longitudinal axis (2921) in the direction of the arrow (2932) as shown in FIG. 29C (2932). This can make it possible to make the diameter (2934) of the tissue (2930) to be excised larger than the diameter of the retriever (2920). In some variations, by twisting the retriever, the diameter of the tissue can be increased by up to about 5 mm, up to about 3 mm, and up to about 1 mm, including all ranges and sub - values therebetween.

[0111]

[0152] In some variations, the retriever (2920) can be configured to be rotated by up to about 30 degrees, up to about 45 degrees, up to about 60 degrees, up to about 90 degrees, up to about 180 degrees, up to about 270 degrees, up to about 360 degrees, up to about 720 degrees, up to about 1,080 degrees, from about 90 degrees to about 720 degrees, from about 180 degrees to about 360 degrees, including all ranges and sub - values therebetween.

[0112]

[0153] In some variations, the handle of the device can be configured to control the rotation of the return (2920) and / or the catheter (2910), and thus enable control of the size of the tissue (2930) to be resected. In some variations, the proximal portion of the ablation device (e.g., the first catheter) can be fixed relative to the rotating distal portion of the ablation device (e.g., the return (2920) and the catheter (2910)).

[0113]

[0154] In some variations, the first portion (2924) can be angled relative to the second portion (2922) in a manner similar to that described in detail herein with respect to FIGS. 26A - 26C. In some variations, the protrusion can include a bend, and the first portion (2924) is an acute angle relative to the second portion (2922). For example, as shown in FIGS. 29A - 29C, the first portion (1924) is an acute angle relative to the longitudinal axis (2921) of the base (2926). The base (2926) is generally cylindrical and can be configured to be coupled to the proximal portion of the catheter (2910) (e.g., the second catheter, the distal - side catheter). For example, the base (2926) can be on the proximal side of a dilator (not shown in FIGS. 29A - 29C).

[0114]

[0155] In some variations, the sheath may be configured to translate relative to the expander (3030) to transition between a first configuration (e.g., a retracted configuration) and a second configuration (e.g., an extended configuration). FIGS. 30A and 30B are side cross-sectional views of a distal portion of an ablation device (3000) including a catheter (3010) (e.g., a second catheter), a sheath (3020), and a distal tip (3030) (e.g., an expander). In some variations, the catheter (3010) and / or the expander (3030) may include one or more lumens (3012). For example, a guidewire (not shown) may be configured to be slidably disposed within the lumen (3012) and / or another catheter (3010). In some variations, the expander (3030) may define a recess (3040) configured to hold (e.g., surround, enclose) the sheath (3020). That is, the sheath (3020) may be configured to seat within the recess (3040). For example, the length of the recess (3040) can be at least equal to the length of the sheath (3020), such that the entire sheath (3020) can fit within the recess (3040). In some variations, the recess (3040) may be defined within the proximal end of the expander (3030).

[0115]

[0156] FIG. 30A shows the ablation device (3000) in a first configuration, where the sheath (3020) is disposed inside the recess (3040) of the expander (3030). In the first configuration, the sheath (3020) may be protected from tissue, which can be beneficial when the catheter (3010) and the expander (3030) are advanced within a patient's body. FIG. 30B shows the ablation device (3000) in a second configuration, where the sheath (3020) is disposed outside the recess (3040) of the expander (3030). In the second configuration, the sheath (3020) may be configured to engage tissue, as described in detail herein.

[0116]

[0157] In some variations, the handle of the device can be configured to control the translational movement of the retractor (3020) and / or the dilator (3030) of the catheter (3010), and thus enable control of the size of the tissue to be excised. For example, the retractor (3020) extending from the dilator (3030) can tent the engaged tissue and increase the diameter of the tissue excised by the ablation device (3000). In some variations, the position of the proximal portion of the ablation device (e.g., the catheter including the electrode) and the dilator (3030) can be fixed relative to the retractor (3020) that is translatable. For example, the retractor (3020) can transition from a first configuration to a second configuration after the dilator (3030) has been advanced through the atrial septum.

[0117]

[0158] In some variations, the retractor can be formed to have sufficient strength to hold the tissue without destroying it. The retractor can include one or more of stainless steel, nitinol, platinum, polyvinyl chloride (PVC), polyethylene (PE), cross-linked polyethylene, polyolefin, polyolefin copolymer (POC), polyethylene terephthalate (PET), polyester, nylon, polymer blend, polyester, polyimide, polyamide, polyurethane, silicone, polydimethylsiloxane (PDMS), PEBAX, combinations thereof, and others.

[0118]

[0159] Additionally or alternatively, the retriever may have one or more of a spiral, helix, corkscrew, and coil shape. FIG. 40A is a side view of a retriever (4000) having a double helix shape, and FIG. 40B is a perspective view. The retriever (4000) may include a base portion (4010), a first protrusion (4020), and a second protrusion (4022). The protrusions (4020, 4022) may each include a distal tip configured to puncture (e.g., bite into) tissue. For example, the retriever (4000) may be configured to rotate and enter (e.g., screw into) the tissue. The protrusions (4020, 4022) may have the same or different shapes and dimensions. In some variations, the catheter may be configured to rotate about its longitudinal axis to twist the retriever (4000) and engage the tissue. As will be described in detail with respect to FIGS. 29A - 29C herein, rotation of the retriever may enable control of the diameter of the tissue to be excised.

[0119]

[0160] In some variations, the retriever may include a series of concentric rings along the length of the second catheter. For example, the retriever may include a series of rings, and the thin radial edges of each ring may be configured to engage the tissue. The tent-like tissue engaged by the retriever may generally be configured to form a conical or cylindrical shape. In some variations, at least a portion of the retriever may include a surface with irregularities or roughness configured to assist in engaging the tissue. In other variations, the retriever may include a stepped structure. In some variations, the protrusions may include a mesh composed of one or more struts. For example, the mesh may be radially arranged around the second catheter and may flare outward.

[0120] Visualization mechanism

[0161] In some variations, the ablation devices and systems described herein may include one or more visualization mechanisms for indirectly visualizing the ablation device. For example, the visualization mechanisms and techniques may facilitate one or more of imaging, positioning, alignment, and operation of the ablation device within a body cavity. For example, indirect visualization techniques include, but are not limited to, ultrasound, fluoroscopy, and X-rays. Elements visualized with fluoroscopy can be aligned with respect to and with the tissue of the catheter, as described in detail herein.

[0121]

[0162] In some variations, the visualization mechanism may be visualized using techniques such as ultrasound and fluoroscopy during operation of the ablation system. For example, a contrast agent may be used to visualize the position and / or orientation of one or more components of the ablation device and of those components with respect to tissue such as the atrial septum. In some variations, the contrast agent (e.g., contrast medium) may include one or more of agitated saline and microbubbles (e.g., CO 2 ). In particular, microbubbles may be used in conjunction with tomographic (e.g., ultrasound) examinations such as echocardiography. For example, microbubbles may receive ultrasonic energy and oscillate and vibrate when reflecting ultrasound. Microbubbles introduced into a body cavity may enhance the contrast of an image at the interface between tissue, blood, and the ablation device.

[0122]

[0163] In some variations, the microbubbles may include a shell and a gas core. For example, the shell of the microbubble may include one or more of albumin, galactose, protein, lipid, polymer, combinations thereof, and others. The gas core of the microbubble may include one or more of air, nitrogen, perfluorocarbon, combinations thereof, and others.

[0123]

[0164] Generally, the diameter of the microbubbles can be from about 1 μm to about 1 mm, from about 1 μm to about 5 μm, from about 1 μm to about 10 μm, from about 10 μm to about 50 μm, from about 50 μm to about 0.1 mm, from about 0.1 mm to about 0.5 mm, from about 0.5 mm to about 1 mm, and all ranges and sub-values therebetween are included.

[0124]

[0165] In some variations, the ablation device described herein can be configured to expel microbubbles for indirect visualization. FIG. 31A is a side view of an ablation device (3100) including a first catheter (3110), an electrode (3120), and a dilator (3150). In some variations, the dilator (3150) can include one or more fluid ports (3160) configured to expel microbubbles. That is, as described in detail herein, microbubbles can be introduced (e.g., injected) into the body cavity when the ablation device (3100) is in a closed configuration. FIG. 31A shows a plurality of fluid ports (3160) radially arranged along the circumference proximal to the dilator (3150). In some variations, the microbubbles can be delivered within the lumen of the electrode (3120) and configured to flow out of the ablation device (3100) through one or more of the fluid ports (3160).

[0125]

[0166] Additionally or alternatively, the electrode (3120) can include one or more fluid ports, as described in more detail with respect to FIGS. 42A and 42B. For example, the distal end of the electrode can include one or more holes (e.g., openings, slits, channels, recesses, protrusions) configured to expel microbubbles. In some variations, any portion of the electrode (3120) can include a fluid port (3160).

[0126]

[0167] Figure 31B is a side cross-sectional view of an ablation device (3100) including a first catheter (3110), an electrode (3120), a second catheter (3130), a return (3140), and an expander (3150). The ablation device (3100) in the closed configuration shown in Figure 31B shows the return (3140), microbubbles (3170), and the proximal end of the expander (3150) surrounded within the lumen of the electrode (3120). One or more of the first catheter (3110) and the second catheter (3130) may be configured to discharge a contrast agent (3170) (e.g., microbubbles) from their respective contrast agent lumens (not shown in Figure 31B). For example, the contrast agent (3170) may be discharged into the lumen of the electrode (3120) and then discharged outside the ablation device (3100) through the fluid port (3160).

[0127]

[0168] In some variations, a contrast agent (e.g., microbubbles) may be introduced (e.g., injected) into the body cavity when the ablation device (3100) is in the closed configuration, within the lumen of the electrode (3120). Figure 31C is a detailed side cross-sectional view of the ablation device (3100). In some variations, the expander (3152) may include a mating surface (3152) configured to engage the distal end of the electrode (3120) in the closed configuration, similar to that described with respect to Figures 6A - 6C and 9A - 9B. As shown in Figure 31C, the contrast agent (3170) may be configured to flow outside the fluid port (3160) through the space between the inner diameter of the electrode (3120) and the outer diameter of the proximal end of the expander (3150). Thus, the contrast agent (3170) may be discharged from the ablation device (3100) through the fluid port (3160). When the mating surface is not pressed against the electrode (3120) (e.g., when the operator pulls in the handle applying the preload force), the ablation device (3100) may be configured to discharge microbubbles from the fluid port (3160). Thus, one or more fluid ports (3160) of the expander (3150) may be configured to discharge the contrast agent (3170) received from the lumen of the electrode (3120).

[0128]

[0169] FIGS. 31D, 31E, and 31F are perspective views of the distal end of an ablation device (3100) including a first catheter (3110), an electrode (3120), a second catheter (3130), a return (3140), and an expander (3150). The ablation device (3100) is arranged in an open configuration to assist in illustrating various fluid port configurations (3160, 3162, 3164) of the expander (3150). The fluid ports (3160, 3162, 3164) can be configured such that a contrast agent (e.g., microbubbles) can flow from the lumen of the electrode (3120) to the outside of the ablation device (3100). Without the fluid ports (3160, 3162, 3164), the contrast agent can be sealed within the lumen of the electrode (3120) when the ablation device (3100) is in a closed configuration, so it is necessary to separate the electrode (3120) from the expander (3150). In contrast, with the fluid port (3160), the contrast agent can flow from the closed configuration into the body cavity.

[0129]

[0170] In some variations, the fluid port (3160) can include shapes including, but not limited to, holes, openings, slits, channels, recesses, protrusions, pores, depressions, combinations thereof, and others. FIG. 31D shows a fluid port (3160) configuration including a plurality of longitudinal channels arranged along the proximal portion of the expander (3150) proximal to the mating surface (3152) of the expander (3150). FIG. 31E shows a fluid port (3162) configuration including a plurality of recesses arranged within the mating surface (3152) of the expander (3150). FIG. 31F shows a fluid port (3164) configuration including a combination of the longitudinal channels of FIG. 31D and the recesses of FIG. 31E. In some variations, the ablation device (3100) can include one or more fluid ports (3160). For example, the ablation device (3100) can include up to about 3 fluid ports, up to about 5 fluid ports, up to about 7 fluid ports, up to about 10 fluid ports, up to about 20 fluid ports, up to about 50 fluid ports, up to about 75 fluid ports, up to about 100 fluid ports, including all values and sub - ranges therebetween.

[0130]

[0171] As shown in FIGS. 42A and 42B, the electrode (4200) may include one or more fluid ports (4220). For example, the distal end (4210) of the electrode (4200) may include one or more fluid ports (4220) (e.g., holes, openings, slits, channels, recesses, protrusions, outlets) configured to discharge fluid (e.g., contrast agent, contrast medium, microbubbles). For example, the diameter of the fluid port (4220) may be at least the same as the diameter of the microbubbles, and the microbubbles can pass through it. In some variations, the fluid ports of the electrode (4200) may be aligned or offset from the fluid ports of the dilator. In some variations, the fluid ports described herein may be formed by laser cutting. In some variations, any portion of the electrode (4200) may include a fluid port (4220).

[0131]

[0172] FIG. 33A is a side view of the distal portion (3310) (e.g., dilator, distal tip) of the ablation device (3300), and FIG. 33B is a side cross-sectional view. In some variations, the dilator (3310) may include a lumen (3312), a proximal end (3314), a mating surface (3316), and one or more visualization mechanisms (3320, 3222). In some variations, the visualization mechanisms (3320, 3222) may correspond to echo-generating regions.

[0132]

[0173] In some variations, the echo-generating region may include one or more microspheres, recesses, protrusions, channels, grooves, scratches, edges, serrations, blind holes, ridges and valleys, undercuts, combinations thereof, and others. For example, the diameter of one or more microspheres, recesses, or protrusions may be from about 5 μm to about 100 μm. In some variations, the microspheres may include a gas core. The microspheres may include glass.

[0133]

[0174] In some deformation forms, the echo generation region may include one or more parts of the expander. For example, FIGS. 33A and 33B show the proximal part (3314) without the visualization mechanisms (3320, 3222). In some deformation forms, the echo generation region may include a plurality of texture patterns. For example, the first texture pattern may be arranged along the distal end of the expander (3310), and the second texture pattern may be arranged along the proximal end of the expander (3310). This may assist in identifying different parts of the expander (3310). In some deformation forms, the texture patterns may include shapes such as circumferential, radial, hatched, random, linear, curved, spiral, oval, ellipsoid, sine wave, polygonal, non-linear, combinations thereof, and others, but are not limited thereto.

[0134]

[0175] In some deformation forms, the echo generation region may include a visualization mechanism (such as a recess, a protrusion, etc.) at a density of about 5% to about 50%, about 10% to about 40%, about 20% to about 30%, about 5% to about 10%, about 10% to about 20%, about 30% to about 40%, about 40% to about 50%, including all numerical values and partial ranges therebetween.

[0135]

[0176] In some deformation forms, the echo generation region may be on and / or under the surface of the expander (3310). For example, FIG. 33A shows a schematic (e.g., not to correct scale) representation of a plurality of microspheres formed on the surface of the expander (3310). In some deformation forms, the echo generation region may include one or more surface textures or patterns on the surface of the expander (3310). In some deformation forms, the surface texture of the echo generation region may be generated using one or more of injection molding, laser engraving, polishing, grooving, etching, vapor deposition, combinations thereof, and others.

[0136]

[0177] Figure 33B shows a schematic representation of a plurality of microspheres formed under the surface of the expander (3310). In some variations, a heat treatment (e.g., vesiculation) may be applied to the expander (3310) to generate one or more microspheres under the surface of the expander (3310). For example, by heating the expander (3310) to a temperature above the melting point of the material of the expander (3310) (e.g., plastic), vaporization of a volatile compound can be induced to form microbubbles containing voids under the surface of the expander. In some variations, the expander may be formed using microspheres such as glass beads disposed under the surface of the expander (3310). In some variations, the surface of the expander (3310) may be treated with a high-temperature heat source (e.g., flame, laser) in a short burst (e.g., less than one second), thereby melting the surface rather than the entire thickness of the expander (3310). Additionally or alternatively, glass microspheres may be incorporated into the resin base material that is injection molded to form the expander (3310).

[0137]

[0178] Additionally or alternatively, fluoroscopy is a technique for real-time X-ray imaging and can be used to guide the insertion and movement of a catheter within a blood vessel. Generally, in fluoroscopy, an X-ray beam is emitted from a fluoroscope so as to pass through the region of interest within the body. An object to be visualized (e.g., an ablation device) can be imaged using an image intensifier tube. Thus, a user viewing the real-time image shown by the image intensifier tube can identify the orientation and alignment of the catheters relative to each other.

[0138]

[0179] In some variations, one or more of the first and second catheters may include a metal-based radiopaque marker including one or more of a ring, a band, and an ink (e.g., platinum, platinum-iridium, gold, nitinol, palladium) configured to enable visualization by fluoroscopy.

[0139]

[0180] The ablation device described in this specification may include any radiopaque metal, such as tungsten, platinum iridium, stainless steel, titanium and tungsten-filled polymers, zirconia ceramics or any suitable radiopaque material, etc. The visualization mechanism may be disposed at any suitable position on or within the surface of the catheter (for example, one or more outer surfaces of the device, inside the catheter or others). In some variations, one or more portions of the ablation device may be fabricated from a radiopaque material, or the visualization mechanism may be attached to the device by any suitable method, such as mechanical attachment (for example, being embedded in a part of the catheter, surrounding along the circumference or others), bonding with an adhesive, welding, soldering, combinations thereof or others.

[0140] Sensor

[0181] In some variations, the ablation devices and systems described herein may include one or more sensors. Generally, the sensors described herein may be configured to transmit and / or receive signals corresponding to one or more parameters. In some variations, the sensors may include pressure sensors, temperature sensors, electrical sensors (for example, impedance sensors, voltage sensors for detecting signals such as electromyogram, electrocardiogram, etc. and others), magnetic sensors (for example, RF coils), electromagnetic sensors (for example, infrared photodiodes, optical photodiodes, RF antennas), force sensors (for example, strain gauges), flow rate or velocity sensors (for example, hot wire anemometers, vortex flow meters), acceleration sensors (for example, accelerometers), chemical sensors (for example, pH sensors, protein sensors, glucose sensors), oxygen sensors (for example, pulse oximetry sensors, myocardial oxygen consumption sensors), voice sensors (for example, microphones for detecting heart murmurs, auscultation), sensors for detecting other physiological parameters (for example, sensors for detecting heart wall, heart rate, respiratory rate, arrhythmia), stimulation devices (for example, for stimulation and / or pacing functions), combinations thereof and one or more of others. In some variations, the impedance sensor may be configured to monitor the impedance between the electrode and the return electrode to confirm the completion of tissue resection.

[0141] Guide wire

[0182] In some variations, the guide wire may be slidably disposed within the ablation device and configured to pass through the atrial septum (e.g., using a standard transseptal puncture method). In some variations, the first and second catheters of the ablation device may translate along the guide wire relative to each other and / or relative to the atrial septum. For example, the guide wire may include one or more of stainless steel, nitinol, platinum, and other suitable biocompatible materials.

[0142] Catheter

[0183] Generally, the catheters described herein may be configured to deliver electrodes and returns to one or more heart chambers to excise tissue such as the atrial septum. In some variations, the catheter may include a shaft composed of a flexible polymeric material such as Teflon, nylon, Pebax, combinations thereof, and the like. In some variations, the ablation device may include one or more operable or deflectable catheters (e.g., one-directional, two-directional, four-directional, multi-directional). In some variations, the first catheter may include one or more pull wires configured to manipulate or deflect a portion of the first catheter. In some variations, the bending radius of the first catheter may be from about 45 degrees to about 270 degrees. In some variations, the second catheter described herein may define a lumen through which a guide wire may pass.

[0143]

[0184] In some variations, the catheter may be woven and / or meshed and fabricated from materials (e.g., nylon, stainless steel, polymer) configured for pushability and flexibility of the catheter. In some variations, the first catheter may have a predetermined curved shape configured to guide the second catheter toward the septum at a predetermined orientation and angle.

[0144]

[0185] Figures 34A and 34B are side cross-sectional views of the distal end of the first catheter (3410) of the ablation device (3400). In some variations, the distal portion of the first catheter (3410) may include a predetermined bend (e.g., a pre-curved tip) as shown in FIG. 34A. For example, due to the predetermined bend, the distal end of the first catheter (3410) can be oriented at a predetermined angle with respect to tissue such as the atrial septum. In some variations, the angle of the predetermined bend can be an angle of about 30 degrees to about 70 degrees.

[0145]

[0186] In some variations, the distal portion of the first catheter (3410) can be positioned at a predetermined position and / or orientation (e.g., substantially perpendicular to the tissue wall) by deflecting the first catheter (3410) (e.g., controlling its bend). In some variations, the first catheter actuator (3430) can be configured to deflect the distal end of the first catheter (3410) while electrically connecting the electrode (3430) to a signal generator (not shown). In this way, the first catheter actuator (3430) can simultaneously perform the function of a pull wire configured to manipulate the first catheter (3410) and deliver energy to the electrode (3420).

[0146]

[0187] In some variations, the ablation device (3400) can include a first catheter (3410), an electrode (3420) coupled to the distal end of the first catheter (3410), and a first catheter actuator (3430) coupled to the electrode (3420). For example, the first catheter actuator (3430) can be electrically coupled to the electrode (3420). In some variations, the first catheter actuator (3430) can be coupled (e.g., fixed, welded, laser welded) to the inner surface of the electrode (3420). Thus, by pulling the first catheter actuator (3430), a predetermined amount of tension can be applied to the distal portion of the first catheter (3410). The first catheter actuator (3430) can have a longitudinal axis that is offset and parallel to the central longitudinal axis (not shown) of the first catheter (3410). By pulling the first catheter actuator (3430), a bending moment can be created between the central longitudinal axis of the first catheter (3410) and the radius at which the first catheter actuator (3430) is coupled to the electrode (3420).

[0147]

[0188] The electrode (3420) can be configured to ablate tissue using a current supplied from a signal generator through a conductor (e.g., a lead wire) of the first catheter actuator (3430). In some variations, the first catheter actuator (3430) can include a pull wire that extends along the length of the first catheter (3410). The proximal end of the first catheter actuator (3430) can be configured to be coupled to an actuation mechanism. For example, the handle can include an actuation mechanism configured to operate the first catheter (3410) via the first catheter actuator (3430). That is, as shown in FIG. 34B, tension and compression can be applied to the first catheter actuator (3430) to deflect (e.g., change the angle of) the distal portion of the first catheter (3410). Thus, separate pull wires and lead wires are not required, and the ablation device (3400) can be miniaturized and its manufacturing cost reduced.

[0148]

[0189] FIGS. 34C and 34D are side cross-sectional views of a variant of the ablation device (3400). FIG. 34C shows an ablation device (3400) including one first catheter actuator (3430), and FIG. 34D shows an ablation device (3400) including a pair of first catheter actuators (3430, 3432). The first catheter actuators (3430, 3432) can each be configured to be electrically connected to the electrodes for redundancy.

[0149]

[0190] FIG. 34C shows an ablation device (3400) including a first catheter (3410) that defines a first catheter lumen (3412) and a first catheter actuator lumen (3434). In some variants, the first catheter actuator (3430) can include a lead wire (3431), which includes an insulator surrounding the electrode wire. In some variants, the insulator can be configured as a slidable channel. The insulator can include, for example, PTFE, PEEK, polyimide, combinations thereof, and others. In some variants, the first catheter actuators (3430, 3432) can be connected to the inner wall of the first catheter (3410) along the length of the first catheter (3410).

[0150]

[0191] In some variations, the plurality of first catheter actuators can further assist in the operability of the ablation device and improve its control. For example, the first catheter actuators can be actuated together to provide a push-pull motion (e.g., one actuator is configured to pull and the other actuator is configured to push). FIG. 34D shows an ablation device (3400) including a first catheter (3410) that defines first catheter actuator lumens (3434, 3436) each having a first catheter actuator (3430, 3432). In some variations, the first catheter actuators (3430, 3432) can be disposed on respective sides of the first catheter (3410). In some variations, the first catheter actuator lumens (3434, 3436) can have a "D" shape.

[0151]

[0192] In some variations, the first catheter actuators can be made of stainless steel. In some variations, the first catheter (3410) can include a core (3411) (e.g., PTFE) configured to hold the alignment and radial position of the first catheter actuators (3430, 3432).

[0152] Expander

[0193] Generally, the dilator described herein can be configured to pierce tissue such as the atrial septum and allow one or more portions of the ablation device to advance into a body cavity such as the left atrium of the heart. In some variations, the dilator can generally be configured to expand tissue such as the atrial septum. The dilator can be atraumatic in shape to minimize any inadvertent or unintended damage. The dilator can include a tapered portion of about 1 degree to about 45 degrees to facilitate passage of the device through the septum and into the left atrium. In some variations, the dilator can include thermoplastic polymers, nylon, polyurethane, ABS, acetal, polycarbonate, PET, PEBA, PEEK, PTFE, silicone, PS, PEI, latex, sulfates, barium sulfate, copolymers, combinations thereof, and others. As described in more detail herein, the dilator can include one or more visualization mechanisms such as fluid ports and echo-generating regions.

[0153]

[0194] In some variations, the dilator of the ablation device can be configured to assist in the tissue compression and / or resection process. As described herein, the distal end of the electrode can be configured to abut the corresponding mating surface of the dilator. For example, a second catheter can be retracted relative to the first catheter such that the mating surface can apply a preload force to the electrode. When the tissue between the electrode and the mating surface is compressed (by the preload force), the thickness of the tissue to be resected can be reduced, whereby the septum can be resected more quickly and with less energy. Further, tissue compression can hold (e.g., fix, lock) the tissue in a predetermined position relative to the ablation device, ensuring that only a predetermined portion of the tissue is resected. In some variations, during application of electrical energy, tissue compression can cause tissue layers (e.g., left and right atrial septal layers) to fuse during resection, thereby reducing the surface area of the tissue exposed along the perimeter of the anastomosis after tissue resection. Tissue compression can also reduce the volume of the tissue.

[0154]

[0195] In some variations, the dilator may be configured to electrically short circuit upon contact with the electrode when the tissue is completely resected. Thereby, the formation of the cutting plasma is stopped, and excessive energy delivery, heat, bubble formation, nerve stimulation, and others can be reduced. For example, when the uninsulated distal end of the electrode is energized, a cutting plasma is generated, and the tissue compressed between the electrode and the mating surface of the dilator can be resected. However, when the tissue is resected and separated from the electrode, the electrode is insulated from the conductive path in the body provided by the tissue, and thereby the cutting plasma can disappear. Thus, complete tissue resection can be mechanically performed without using sensors and / or feedback control, and as a result, the resection procedure can be simplified.

[0155]

[0196] FIG. 35A is a side cross-sectional view of the distal end of an ablation device (3500) including a dilator (3510), an insulator (3520), and an electrode (3530). The dilator (3510) may include a lumen (3512), a proximal end (3514), and a mating surface (3516) defining a recess (3518) configured to receive the distal end of the electrode (3530). As shown in FIG. 35A, the distal end of the electrode (3530) is not insulated. In some variations, the mating surface (3518) may include one or more non-conductive and / or heat-resistant portions. In some variations, the mating surface (3518) may be configured to withstand the high temperatures generated during the resection procedure. For example, the non-conductive portion may include one or more of a polymer (e.g., PEEK, polyimide), a ceramic (e.g., zirconia), and aluminum oxide. Thus, the electrode (3530) may be configured to electrically short circuit when the electrode (3530) resected the tissue and engages the recess (3518) of the mating surface (3516).

[0156]

[0197] Additionally or alternatively, the mating surface may include a deformable material. FIG. 35B is a detailed side cross-sectional view of an ablation device (3550) including an expander (3560), an insulator (3570), and an electrode (3580). The expander (3560) may include a proximal end (3564) and a mating surface (3566). In some variations, the mating surface (3516) may be configured to be deformable (e.g., compressible). When the expander (3560) is retracted toward the electrode (3580), tissue disposed between the electrode (3580) and the mating surface (3566) may be compressed together with the mating surface itself.

[0157]

[0198] Additionally or alternatively, the mating surface may function as a dissipating element and / or reinforce power lines, and thus may include a conductive portion configured to focus RF energy (e.g., focused monopolar) to control the vagation of the resection line of tissue during resection. For example, the surface area electrically connected to the electrode by the conductive portion of the expander may be increased, thereby reducing the current density of the electrode below a threshold level sufficient for tissue resection. Thus, the electrode may be configured to contact the conductive mating surface after tissue resection. In some variations, the surface area of the conductive portion of the mating surface may be about 4 times to about 10 times the surface area of the exposed portion of the electrode (e.g., the distal edge of the electrode).

[0158]

[0199] In some variations, the expander may have a length of about 2 mm to about 2 cm. For example, the expander may have a length of about 5 mm to about 1 cm. In some variations, the expander may have a taper of about 5 degrees to about 20 degrees with respect to the longitudinal axis of the expander. In some variations, the distal end of the expander may be non-invasive (e.g., rounded, blunted). As described herein, the return may be connected to the proximal end of the expander.

[0159] Handle

[0200] Generally, the handle described herein can be configured such that an operator can grip it to control one or more of the position, orientation, and operation of the ablation device. In some variations, the handle can include an actuator that enables translational movement and / or rotation of the first and second catheters, in addition to operation by an optional delivery catheter. The return deployment can be performed by a deployment mechanism (e.g., a screw / rotation mechanism, a translational movement mechanism, a slider) in some variations. In some variations, the handle can be configured to limit the applied force that a user can apply to the advancement and retraction of the catheter shafts relative to each other. For example, the handle can be configured to excise tissue and / or apply energy to an electrode to control one or more sensors. In some variations, the handle can be connected between a signal generator and the ablation device.

[0160]

[0201] FIG. 39A is a perspective view of a handle (3900) of an ablation device, and FIG. 39B is a plan view. In some variations, the handle (3900) can include one or more actuation mechanisms (3910), fluid ports (3920), and a removable electrical connector (3930). The handle (3900) can be connected to the proximal end of a first catheter (3950). In some variations, the handle (3900) can be configured such that an operator can hold (e.g., grip) it to enable control of one or more of catheter deflection (e.g., operability), tissue excision (e.g., energy delivery to an electrode), catheter translational movement (e.g., transition between open and closed configurations, tissue compression), and visualization (e.g., contrast fluid delivery).

[0161]

[0202] For example, the actuation mechanism (3910) can be configured to control the preload force of the dilator of the second catheter applied to the electrodes of the first catheter, which is described in detail herein. In some variations, the actuation mechanism (3910) can include a plurality of predetermined stop members and thereby can include a screw mechanism that allows an operator to select the amount of preload at the distal end of the ablation device. For example, the operator can select a predetermined preload force using the actuation mechanism (3910) when the ablation device is in the resection configuration and the tissue is compressed between the electrode and the dilator. In some variations, the actuation mechanism (3910) can be coupled to the shaft of the second catheter, whereby the actuation mechanism (3910) can be configured to pull the distal portion of the second catheter toward the handle (3900) using a screw mechanism.

[0162]

[0203] In some variations, the actuation mechanism (3910) can be configured to actuate one or more first catheter actuators as described herein. For example, the first catheter actuator can be configured to manipulate and / or deflect the distal end of the first catheter. That is, the actuation mechanism (3910) can be configured to push and / or pull the first catheter.

[0163] Signal generator

[0204] Generally, the signal generator described herein can be configured to provide energy (e.g., an energy waveform) to an ablation device for excising a predetermined portion of tissue such as an atrial septum. In some variations, the ablation system described herein can include an energy source and a signal generator having a processor configured to deliver a waveform for delivering energy to tissue (e.g., an atrial septum). The waveforms described herein can assist in forming anastomoses. In some variations, the signal generator can be configured to control the generation and delivery of the waveform in response to received sensor data. For example, energy delivery can be suppressed unless pressure sensor measurements confirm engagement and compression of the tissue between the electrode and the corresponding mating surface.

[0164]

[0205] The signal generator can generate and deliver several types of signals including, but not limited to, high frequency (RF), direct current (DC) impulses, stimulation range impulses, and / or hybrid electrical impulses. For example, the signal generator can generate single-phase (DC) pulses and two-phase (DC and AC) pulses. The signal generator can include a processor, a memory, an energy source, and a user interface. The processor can receive data received from one or more of the memory, the energy source, the user interface, and the ablation device. The memory can further store instructions that cause the processor to execute system-related modules, processes, and / or functions such as waveform generation and delivery. For example, the memory can be configured to store patient data, clinical data, treatment data, and others.

[0165]

[0206] In some variations, the signal generator can be configured to generate alternating current, voltage, and / or power within a high frequency spectrum of about 9 kHz to about 300 MHz at an output level of about 5 W to about 500 W. In some variations, the RF generator can operate by outputting a constant voltage, constant power, and / or constant current. In some variations, the RF generator outputs a constant sine wave over the period of tissue resection. For example, the RF generator can be configured to output a sine wave of about 400 kHz to about 600 kHz, about 450 kHz to about 550 kHz, about 475 kHz to about 525 kHz, including all numerical values and subranges therebetween. In some variations, the RF signal output is interrupted and attenuated so that the RF energy is applied over a certain percentage of the operating time.

[0166]

[0207] In some variations, the signal generator can be configured to synchronize energy delivery with a predetermined phase of the patient's cardiac cycle. For example, the sensor can be configured to measure an ECG signal, and the signal generator can be configured to deliver a signal waveform based on (e.g., in synchronization with) the ECG signal. Additionally or alternatively, a pacing signal for cardiac stimulation can be generated and used to deliver the signal waveform by the signal generator in synchronization with the pacing signal.

[0167]

[0208] FIG. 37 is a voltage waveform (3700) of an exemplary variation of an ablation procedure that includes a first waveform (e.g., an overshoot spike) (3710) and a second waveform (e.g., a substantially steady-state voltage) (3720). In some variations, the signal generator can be configured to generate a first waveform (3710) followed by a second waveform (3720), and the first waveform has a voltage higher than a second voltage of the second waveform. The first waveform (3710) can be configured to rapidly ablate tissue during energy delivery. The second waveform of lower voltage (3720) can reduce heat propagation, bubbling, nerve stimulation, and one or more of the others. The second waveform can be configured to dry the ablated tissue held within the ablation device, thereby assisting in tissue confinement and compartmentalization.

[0168]

[0209] Alternatively, the first waveform can be configured to dry the tissue. For example, the first waveform can include a voltage lower than the ionization threshold of the vapor (e.g., less than about 130 volts) over a duration from about 100 milliseconds to about 60 seconds. Impedance can be monitored to prevent plasma formation.

[0169]

[0210] Generally, a processor (e.g., a CPU) described in this specification can process data and / or other signals to control one or more components of a system. The processor can be configured to receive, process, edit, calculate, store, access, read, write, and / or transmit data and / or other signals. In some variations, the processor can be configured to access or receive data and / or other signals from one or more of sensors (e.g., pressure sensors) and storage media (e.g., memory, flash drive, memory card). In some variations, the processor can be any suitable processing device configured to run and / or execute a series of instructions or code, and can include one or more data processors, image processors, graphics processing units (GPUs), physical processing units, digital signal processors (DSPs), analog signal processors, mixed signal processors, machine learning processors, deep learning processors, finite state machines (FSMs), compression processors (e.g., for data compression to reduce data rate and / or memory requirements), encryption processors (e.g., for protecting wireless data and / or power transmission), and / or central processing units (CPUs). The processor can be, for example, a general-purpose processor, a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a processor board, and / or others. The processor can be configured to run and / or execute application processes and / or other modules, processes, and / or functions related to the system. The underlying device technology can be provided by various types of components (e.g., metal-oxide semiconductor field-effect transistors (MOSFETs) such as complementary metal-oxide semiconductor (CMOS), bipolar technologies such as emitter-coupled logic (ECL), polymer technologies (e.g., silicon-conjugated polymers and metal-conjugated polymer-metal structures), analog-digital hybrids, and others).

[0170]

[0211] The systems, devices, and / or methods described herein can be implemented by software (executed on hardware), hardware, or combinations thereof. Hardware modules can include, for example, general-purpose processors (or microprocessors or microcontrollers), field-programmable gate arrays (FPGAs), and / or application-specific integrated circuits (ASICs). Software modules (executed on hardware) can be expressed in various software languages (e.g., computer code), including C, C++, Java®, Python, Ruby, Visual Basic®, and other object-oriented, procedural, or other programming languages, as well as development tools. Examples of computer code include, but are not limited to, microcode or microinstructions, machine instructions such as those generated by a compiler, code used to generate web services, and files containing higher-level instructions that are executed by a computer using an interpreter. Other examples of computer code include, but are not limited to, control signals, encryption code, and compression code.

[0171]

[0212] Generally, the ablation device described herein may include a memory configured to store data and / or information. In some variations, the memory may include random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), a memory buffer, erasable programmable read-only memory (EPROM), electrically erasable read-only memory (EEPROM), read-only memory (ROM), flash memory, volatile memory, non-volatile memory, combinations thereof, and one or more of others. In some variations, the memory may store instructions that cause a processor to execute modules, processes, and / or functions related to the ablation device, such as generation of a signal waveform, control of the ablation device, transmission of data and / or signals, reception of data and / or signals, and / or communication. Some variations described herein may relate to a computer storage product having a non-transitory computer-readable medium (which may also be referred to as a non-transitory processor-readable medium) having instructions and computer code thereon for performing various computer-implemented operations. The computer-readable medium (or processor-readable medium) is non-transitory in that it does not include a transitory propagation signal per se (e.g., a propagating electromagnetic wave that carries information on a transmission medium such as air or cable). The medium and the computer code (which may also be referred to as code or an algorithm) may be designed and constructed for one or more particular uses.

[0172]

[0213] In some variations, the ablation device may further include a communication device configured to allow an operator to control one or more of the devices of the ablation system. The communication device may include a network interface configured to connect the ablation device to other systems (e.g., the Internet, a remote server, a database) by a wired or wireless connection. In some variations, the ablation device may communicate with other devices (e.g., a cell phone, a tablet, a computer, a smart watch, and others) via one or more wired and wireless networks. In some variations, the network interface may include one or more of a wireless receiver / transmitter, an optical (e.g., infrared) receiver / transmitter, and others configured to communicate with one or more devices and / or networks. The network interface may communicate with one or more of the ablation device, the network, the database, and the server, either wired and / or wirelessly.

[0173]

[0214] The network interface may include an RF circuit configuration configured to receive and / or transmit RF signals. The RF circuit configuration may perform a conversion between an electrical signal and an electromagnetic signal and communicate with a communication network and other communication devices via the electromagnetic signal. The RF circuit configuration may include well-known circuit configurations for performing these functions, including, but not limited to, an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a mixer, a digital signal processor, a CODEC chipset, a subscriber identity (SIM) card, a memory, and the like.

[0174]

[0215] Wireless communication through any of the machines can use any of a plurality of communication standards, protocols, and technologies, including, but not limited to, Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), Evolution, Data-Only (EV-DO), HSPA, HSPA+, Dual-Cell HSPA (DC-HSPDA), Long-Term Evolution (LTE), Near Field Communication (NFC), Wideband Code Division Multiple Access (W-CDMA), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Bluetooth, Wireless Fidelity (WiFi) (e.g., IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, and others), Voice over Internet Protocol (VoIP), Wi-Max, protocols for email (e.g., Internet Message Access Protocol (IMAP) and / or Post Office Protocol (POP)), instant messaging (e.g., Extensible Messaging and Presence Protocol (XMPP), Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions (SIMPLE), Instant Messaging and Presence Service (IMPS)), and / or Short Message Service (SMS) or any other suitable communication protocol. In some variations, the devices of the present application can communicate directly with each other without performing data transmission through a network (e.g., through NFC, Bluetooth, WiFi, RFID, and others).

[0175]

[0216] In some alternative forms, the user interface may include an input device (e.g., a touch screen) and an output device (e.g., a display device), and may be configured to receive input data from one or more of an ablation device, a network, a database, and a server. For example, an operation by an operator on an input device (e.g., a keyboard, a button, a touch screen) may be received by the user interface, and then processed by a processor and a memory, and the user interface may output a control signal to the ablation device. Some alternative forms of the input device may include at least one switch configured to generate a control signal. For example, the input device may include a touch surface for an operator to provide an input corresponding to a control signal (e.g., touching the touch surface with a finger). An input device including a touch surface may be configured to detect contacts and movements on the touch surface using any of a plurality of touch sensitivity technologies including capacitance, resistance, infrared, optical imaging, distributed signal, voice pulse recognition, and surface acoustic wave technology. In an alternative form of the input device including at least one switch, the switch may include at least one of, for example, a button (e.g., a hard key, a soft key), a touch surface, a keyboard, an analog stick (e.g., a joystick), a direction pad, a mouse, a trackball, a jog dial, a step switch, a rocker switch, a pointer device (e.g., a stylus), a motion sensor, an image sensor, and a microphone. The motion sensor may receive data on the movement of the operator from an optical sensor and classify the gesture of the operator into a control signal. The microphone may receive voice data and recognize the voice of the operator as a control signal.

[0176]

[0217] To provide additional sensory output (e.g., force feedback) to the operator, a tactile device may be incorporated into one or more of the input and output devices. For example, the tactile device may generate a tactile response (e.g., vibration) to confirm an input by the operator to the input device (e.g., a touch surface). As another example, the tactile feedback may notify that the input of the operator has been invalidated by the ablation device.

[0177]

[0218] II. Method This specification also describes a method of forming an anastomosis in a patient's atrial septum using the systems and devices described herein. Specifically, the systems, devices, and methods described herein can be used to capture, excise, and remove a predetermined portion of tissue to create an anastomosis for treating heart failure. In some variations, the method of forming an anastomosis can include advancing a device into the patient's right atrium. A guidewire can be advanced through the atrial septum of the heart into the left atrium. The device can include an expander configured to perforate the septum such that a first catheter is disposed within the right atrium and a second catheter is disposed within the left atrium. The second catheter can include a retriever configured to engage and secure tissue when retracted relative to the first catheter. When the retriever is further retracted (e.g., toward the right atrium), the engaged tissue can be stretched and / or pressed against the retriever, forming a "tent" shape by the elasticity of the tissue. The retriever and the engaged tent-shaped tissue can be retracted into the lumen of an electrode (e.g., a tubular electrode). By positioning ablation devices on both sides of the atrial septum, a predetermined force can be applied to engage and / or compress a predetermined portion of the septal tissue to be excised. For example, the electrodes of the first catheter can press the septal tissue against the proximal end (e.g., the mating surface) of the expander. The electrodes disposed within the right atrium can be energized and can cut (e.g., excise) tissue with RF energy using an ablation waveform, as described in more detail herein. The excised tissue can be surrounded by the ablation device to prevent tissue loss. For example, the excised tissue can be held by the retriever and the electrodes can surround the excised tissue and the retriever. Thus, the ablation devices described herein can be configured to safely and efficiently form an interatrial anastomosis.

[0178]

[0219] Figure 18 is a flowchart generally illustrating a variant form of an anastomosis formation method (1800). The method (1800) may include advancing an ablation device including a first catheter and a second catheter into the right atrium of a patient (1802). For example, the ablation device may be advanced along a guidewire and inserted from a femoral vein, for example, using a transseptal puncture method. In some variants, the ablation device within the right atrium may be oriented substantially perpendicular to the atrial septum. For example, the first catheter actuator described herein may be configured to deflect the distal portion of the ablation device to change the position of the ablation device relative to the atrial septum. The first catheter may abut the second catheter when advanced within the heart. For example, a delivery catheter may be configured to hold each of the first catheter and the second catheter until they are deployed within the heart.

[0179]

[0220] The catheters of the ablation device may be indirectly visualized as needed throughout the ablation procedure. Indirect visualization, such as with an echocardiogram and / or a fluoroscope, may assist the operator in positioning and / or aligning the ablation device relative to the tissue. For example, under ultrasonic imaging, a contrast agent, such as microbubbles, may be introduced into the pericardial cavity using the ablation device, whereby the electrodes and / or dilators are positioned relative to the atrial septum disposed therebetween. Accordingly, the user may bring the catheter very close to compress and ablate the tissue. In some variants, the ablation device may be configured to expel microbubbles in a closed configuration for ultrasonic visualization of the ablation device and the atrial septum.

[0180]

[0221] In some variations, the contrast agent can be introduced into the heart through the fluid port of the dilator. In some of these variations, the contrast agent can be introduced into the lumen of the electrode. Additionally or alternatively, the distal end of the ablation device can include an echo generating region, which can receive ultrasonic waves. For example, the distal end of the ablation device can include one or more microspheres having a diameter of about 5 μm to about 100 μm.

[0181]

[0222] FIG. 32 is a side view of an ablation device (3200) within the pericardial cavity. In some variations, the ablation device (3200) can include a first catheter (3210), an electrode (3220), a second catheter (3230), a return (3240), and a dilator (3250). The ablation device (3200) is shown in an open configuration with tissue (e.g., atrial septum) (3280) disposed between the electrode (3220) and the dilator (3250) spaced from the return (3240). In some variations, the first catheter (3120) can be configured to discharge a contrast agent (e.g., microbubbles) (3270) into the lumen of the electrode (3220) and into the pericardial cavity. For example, the contrast agent lumen (3212) of the first catheter (3210) can be configured to discharge the contrast agent (3270) into the lumen of the electrode (3220). Contact between the contrast agent (3270) and the electrode (3220) and the tissue (3280) can enable indirect visualization (e.g., cardiac echo) at one or more steps of the ablation procedure. Visualization of the ablation device (3200) and the tissue (3280) can assist in positioning the electrode relative to the tissue (3280). For example, the contrast agent (3270) can be introduced into the right atrium before engaging the tissue (3280) using the return. The contrast agent (3270) flowing through the lumen of the electrode (3220) and the pericardial cavity can enable visualization of the electrode (3220) and the right atrial side of the atrial septum.

[0182]

[0223] The second catheter can be advanced into the left atrium through the atrial septum (1804). For example, the dilator of the second catheter can be advanced through the atrial septum (e.g., on a guidewire), such that the guidewire and the dilator will be within the left atrium. The second catheter can translate relative to the first catheter. The return of the second catheter can be advanced into the left atrium, such that the electrodes of the first device may be within the right atrium. The septal tissue can slide over the return as it is advanced into the left atrium. As shown in FIGS. 19A and 19B, the ablation device (1900) can be disposed within the right atrium (1990) and advanced into the left atrium (1980) using the dilator of the second catheter (1950). The second catheter (1950) can translate relative to the first catheter and the atrial septum (1970) within the right atrium (1990). The return (1940) of the second catheter (1950) can pass through the septum (1970) and be advanced into the left atrium (1980). As shown in the side cross-sectional view of FIG. 19C, the first catheter (1910) can include a tubular electrode (1920), a lumen (1922), a lead (1924), a connector (1926), and an insulator (1960). The second catheter (1950) can include a return (1940), a mating surface (1954), a dilator, and a dilator lumen (1952).

[0183]

[0224] In some variations, the ablation device can introduce a contrast agent (e.g., microbubbles) to visualize the interface between the dilator, tissue, and electrode. In some variations, the electrodes can be repositioned approximately 2 mm to approximately 5 mm away from the atrial septum based on the visualization.

[0184]

[0225] The second catheter can be retracted relative to the first catheter (1806). For example, the second catheter can be translated towards the first catheter to bring the electrode and the dilator closer to each other. In some variations, the second catheter can be retracted while the first catheter is held in a substantially fixed position within the right atrium. In some variations, a contrast agent (e.g., microbubbles) can be introduced to confirm the position of the return and the tissue and the electrode.

[0185]

[0226] In some variations, retracting the second catheter towards the first catheter can include translating the return relative to the dilator to engage a first portion of the septum. For example, the return can be retracted from the dilator as shown in FIGS. 30A and 30B. Specifically, the first catheter (3030) can transition from a first configuration in which the return (3020) is disposed inside the recess (3040) of the dilator (3030) to a second configuration in which the return (3020) is disposed outside the recess (3040).

[0186]

[0227] When the second catheter is retracted, the return of the second catheter can engage a predetermined portion of the septum (1808). In some variations, as shown in FIGS. 29A - 29C, it can include rotating the return about the longitudinal axis of the return. The size of the first tissue portion excised from the second tissue portion can correspond to the rotation angle of the return. The return can be rotated at a rotation angle of up to about 360 degrees.

[0187]

[0228] As shown in FIG. 19D, when the second catheter (1950) is retracted relative to the first catheter (1910), the snare (1940) can engage the septal tissue (1970). For example, when the snare retracts the second catheter towards the first catheter, it can puncture the first portion. The snare can puncture the first portion, thereby holding the layers of the atrial septum (e.g., the left and right atrial layers) together and reducing tissue separation and / or tissue shearing. Thus, the snare (1940) can maintain the structural integrity of the septum while capturing (e.g., fixing, holding) the tissue (1970). In some variations, the retracted snare can apply a force to the septum to hold and stretch that portion of the septum (e.g., the first portion) on the snare. The force can increase as the second catheter is further retracted towards the first catheter. In some variations, when the second catheter is retracted, a force of at least 20 grams can be applied to the atrial septum. For example, an ablation device can apply a force of about 20 grams to about 30 grams to the atrial septum. In some variations, the first portion of the septum can form a substantially cylindrical shape when retracted into the lumen.

[0188]

[0229] The snares described herein are configured to engage the first portion of the septum without shearing its tissue (e.g., without destroying or tearing one or more layers of the atrial septum), such that the first portion engages the snare and remains intact when retracted into the lumen of the electrode. That is, due to the force applied by the snares described herein, the structural integrity of the first portion is maintained even when the snare punctures the septum. This can ensure that the first portion of the septum to be excised remains held and fixed by the snare throughout the procedure, resulting in improved consistency and safety of the methods described herein.

[0189]

[0230] The septum can be drawn into the lumen of the electrode (1810). In some variations, a portion of the atrial septum can form a tent over the return when the septum is drawn into the lumen of the electrode. In this way, the tissue to be excised can be fixed within the ablation device prior to ablation, reducing the risk of uncontrolled tissue loss within the heart chamber and vascular structures. As shown in FIG. 19E, a portion of the septum (1970) can form a tent-like shape over the return (1940). In some variations, the return (1970) engaged with the tissue can rotate as it is drawn into the lumen of the electrode, applying a rotational force to the stretched (e.g., tent-shaped) septal tissue. In some variations, the size (e.g., diameter) of the tissue to be excised (1970) can be controlled by varying the distance that the engaged tissue (1970) is drawn into the lumen (1922). Thus, the size of the anastomosis can be independent of the diameter of the electrode. By pulling a second catheter towards the first catheter, the ablation device (1900) engages the tissue, stretches it, compresses it, locks it, tents it, and controls the size of the opening to be excised. In some variations, the size of the anastomosis can depend on the distance that the return is drawn into the electrode, such that the size of the anastomosis can be independent of the diameter of the ablation device.

[0190]

[0231] In some variations, a contrast agent (e.g., microbubbles) can be introduced to confirm the position of the return, tissue, and electrode (e.g., confirm that the electrode is within the right atrium).

[0191]

[0232] The septum can be compressed between the electrode and the dilator (1812). As shown in FIG. 19E, a portion of the atrial septum (1970) can be held between the electrode (1920) and the dilator (1950). For example, the electrode and the dilator can be brought closer to each other and abutted (e.g., pressed) against respective sides of the atrial septum (1970), "locking" the tissue (1970) in place relative to the ablation device (1900). In some variations, the force applied to the atrial septum through compression by the retractor (1940) can be applied before and during delivery of the ablation waveform. Compression of the tissue can potentially reduce the applied RF energy required to excise the tissue. In some variations, one or more of the retractor and the dilator can be rotated about the longitudinal axis of the second catheter to further engage and / or compress the tissue.

[0192]

[0233] In some variations, as shown in FIG. 35B, by pulling the second catheter toward the first catheter, the compressible proximal portion of the dilator can be deformed.

[0193]

[0234] FIG. 36A is a side view of an ablation device (3600) within the pericardial cavity, showing the compression step of the excision procedure. In some variations, the ablation device (3600) can include a first catheter (3610), an electrode (3620), a second catheter (3630), a retractor (3640), and a dilator (3650). In some variations, the first catheter (3610) can include a lumen (3612) for a contrast agent, which is described in more detail herein. In some variations, the electrode (3620) can include a lumen configured to hold one or more of the retractor (3640), a first portion (3672) of the tissue, and the proximal portion (3652) of the dilator (3650). In some variations, a guidewire (3630) can be slidably disposed within the second catheter (3630).

[0194]

[0235] As shown in FIG. 36A, the return (3640) can be configured to engage a first portion (3672) of the atrial septum (3670) in an excision configuration where the tissue (3674) is compressed between the distal edge of the electrode (3630) and the proximal portion (3652) of the expander (3650). For example, the distal end of the electrode (3620) can be configured to abut the corresponding mating surface (3652) of the expander (3650). For example, the second catheter (3630) can be retracted relative to the first catheter (3610), and the mating surface (3652) can apply a preload force to the tissue (3674) and the electrode (3620). In some variations, the application of the preload force can be controlled by the operator via the actuator of the handle. Compression of the tissue (via the preload force) between the electrode and the mating surface can also reduce the thickness of the tissue to be excised, allowing the septum to be excised more quickly and with less energy. Further, the compressed tissue can hold (e.g., fix, lock) the tissue in a predetermined position relative to the ablation device, ensuring that only a predetermined portion of the tissue is excised. Compression of the tissue can also reduce the volume of the tissue. In some variations, the preload force can be from about 0.4 N to about 25 N, from about 1 N to about 10 N, from about 5 N to about 10 N, from about 5 N to about 15 N, from about 10 N to about 20 N, and all ranges and sub - values therebetween are included.

[0195]

[0236] In some variations, the compressed tissue (3674) and the expander (3650) can rest in a static equilibrium state where the proximal portion (3652) of the expander (3650) presses the tissue (3674) against the electrode (3620) with a shear force that includes a radial component. In some variations, it is advantageous for the expander (3650) to be stretched prior to excision, as seen by the operator using a fluoroscope. In some variations, the ablation device (3600) (FIG. 36A) in the excision configuration can correspond to the expander (3650) stretching about 1 mm from the end of the electrode (3620).

[0196]

[0237] To excise the septum, ablation waveforms can be delivered to the electrodes (1814). For example, a signal generator can generate a biphasic high-frequency waveform configured to excise a portion of the atrial septum held by the device. In some variations, the electrodes can be configured to transmit a current of 50 mA to 4 A at about 0.1 kV to about 4.0 kV at a rate of up to about 500 kHz.

[0197]

[0238] In some variations, delivery of the ablation waveform can be controlled based on the distance between the electrode and the dilator. For example, the electrode can be configured to electrically short circuit when the electrode contacts the mating surface of the dilator during delivery of the ablation waveform.

[0198]

[0239] In some variations, the ablation waveform can include a first waveform followed by a second waveform. The first waveform can include a first voltage and the second waveform can include a second voltage. The first voltage can be higher than the second voltage.

[0199]

[0240] FIG. 19F shows an ablation device (1900) that defines a predetermined aperture, an atrial septum (1970), and holds excised tissue (1940) within the lumen (1922) of the electrode (1920). As shown in FIG. 19F, the septum (1970) can snap back vigorously when the tissue engaged with the retriever (1840) is excised. The tissue within the lumen (1922) can be sealed within the ablation device (1900) when excision is complete and the electrode contacts the dilator (1950). In this way, the excised tissue can be prevented from being lost in the body.

[0200]

[0241] FIG. 36B shows an ablation device (3600) in a closed (e.g., seated) configuration, where excised tissue (e.g., a first portion) (3672) engages with the retriever (3640) and is held within the lumen of the electrode (3620). The proximal portion (3652) of the dilator (3650) can seat, for example, within the lumen of the electrode (3620). FIG. 36B shows a hole (3676) formed in the atrial septum (3670).

[0201]

[0242] In some variations, the completion of the energy delivery process can be confirmed by visualization. For example, the differences between the ablation device (3600) in the resection configuration (FIG. 36A) and the closure configuration (e.g., FIG. 36B) can be confirmed through indirect visualization. For example, through visualization by a fluoroscope, it can be confirmed, based on the imaged position of the dilator (3650) relative to the electrode (3620), that the tissue is sandwiched between the electrode (3620) and the dilator (3650), and that the tissue has been resected after energy delivery.

[0202]

[0243] In some variations, a preload force (e.g., a first predetermined force) can be applied by the dilator (3650) to the electrode (3620) during and / or after energy delivery, such that the second catheter (3630) can be reliably drawn towards the first catheter (3610). In some variations, the operator can operate a switch within the handle to initiate energy delivery for tissue resection. When the proximal portion (3652) is drawn towards and pressed against the electrode (3620) during energy delivery, the proximal portion (3652) can shear (e.g., cut, separate) the tissue from the septum (3670) with a second predetermined force greater than the first predetermined force. That is, the proximal portion (3652) can function as a cutting board and ensure that even small fibers of the tissue (3574) (e.g., a second portion) are resected from the septum (3670). Alternatively, the preload force can be such that it is not applied to the tissue (3674) and the electrode (3620) when the ablation waveform is delivered to the electrode (3620). During energy delivery, the dilator (3650) can be naturally drawn into the lumen of the electrode (3620) when the tissue (3674) is cut (e.g., ablated).

[0203]

[0244] In some variations, as shown in FIG. 36B, the proximal portion (3652) of the expander (3650) can be arranged within the lumen of the electrode (3620) when the mating surface (e.g., when the proximal portion (3652) engages with the electrode). The proximal portion (3652) arranged within the lumen of the electrode (3620) can securely attach the electrode coaxially to the expander. For example, the expander can be fixed to the first catheter (3610) and be made to withstand being disengaged by a lateral load, such as when an ablation device is advanced following a curved guide wire. Further, the electrode (3620) securely engaged with the expander (3650) can be configured to prevent the ablation device (3600) from catching (e.g., hitting) on blood vessels, tissue (e.g., septal crossing), introducers, sheaths, and others while being advanced and retracted within the body cavity. In some variations, when the mating surface engages with the electrode (3620), about 0.5 mm to about 2 mm of the proximal portion (3652) of the expander (3650) can be arranged within the lumen of the electrode (3620). In some variations, the ablation device (3600) shown in FIG. 36B can be removed from the patient.

[0204]

[0245] The first and second catheters can be removed from the patient (1816). This can include retracting the excised tissue held within the first catheter since the first and second catheters are retracted together. In some variations, the procedure can be imaged by ultrasound and / or fluoroscope during one or more steps.

Example

[0205]

[0246] Figures 20 and 21 are perspective views of alternative forms of ablation devices (2000, 2100). In some alternative forms, the ablation devices (2000, 2100) may include a first catheter (2010, 2110) and a second catheter (2030, 2130). The first catheter (2010, 2110) may include a tubular electrode (2020, 2120). The electrode (2020, 2120) may define a lumen (2022, 2122) configured to hold a return (2040, 2140) of the second catheter (2030, 2130). The tubular electrode (2020, 2120) may include a cylindrical shape. In some alternative forms, the ablation devices (2000, 2100) may include a second catheter (2030, 2130) slidably disposed within the first catheter (2010, 2110). The second catheter (2030, 2130) may include a return (2040, 2140) and an expander (2050, 2150) configured to engage the electrode (2020, 2120). In some alternative forms, the return (2040, 2140) may include a plurality of protrusions angled generally toward the electrode (2020, 2120). The expander (2050, 2150) may have a tapered conical shape. Figure 22 is a perspective view of an ablation device (2200) engaged with excised tissue (2260). In some alternative forms, the ablation device (2200) may include a first catheter (2210) and a second catheter (2230). The excised tissue (2260) fits into the lumen (2222) of the electrode (2220) and is removed from the patient.

[0206]

[0247] Figure 23 is a fluoroscopic visualization image (2300) of ablation devices (2310, 2320) in open and closed configurations, respectively. One or more portions of the ablation devices (2310, 2320) may include radiopaque portions.

[0207]

[0248] FIG. 24 is an image (2400) of an anastomosis (2420) formed in cadaver tissue (2410) using the ablation system and method described herein. FIGS. 25A and 25B are images (2500) of an anastomosis (2520) formed in porcine tissue (2510) using the ablation system and method described herein.

[0208]

[0249] FIGS. 27A and 27B are perspective views of a variant form of an ablation device (2700) engaged with tissue (2760). In some variant forms, the ablation device (2700) may include a first catheter (2710) and a second catheter (2730). The first catheter (2710) may include a tubular electrode (2720). The electrode (2720) may define a lumen (2722) configured to hold a return (2740) of the second catheter (2730). The tubular electrode (2720) may have a cylindrical shape. In some variant forms, the ablation device (2700) may include a second catheter (2730) slidably disposed within the first catheter (2710). The second catheter (2730) may include a return (2740) similar to the variant form shown in FIGS. 26A and 26B and a dilator (2750) configured to engage the electrode (2720). In some variant forms, the return (2740) may include a plurality of protrusions including a tissue engagement portion substantially parallel to the longitudinal axis of the second catheter (2730). The dilator (2750) may have a tapered conical shape.

[0209]

[0250] The tissue (2760) can be configured to engage with the return (2740), as described in more detail herein. In FIGS. 27A and 27B, to show the return (2740) and the excised tissue (2760), the second catheter (2730) is advanced relative to the first catheter (2710), and the excised tissue (2260) fits into the lumen (2722) of the electrode (2720) so that the tissue can be easily removed from the patient's body. In some variations, the lumen (2722) can have a length of at least 1 mm. For example, the lumen (2722) can have a length of about 5 mm to about 4 cm. FIG. 27C is an image (2770) of an anastomosis (2790) formed in the tissue (2780) using the ablation system and method described herein.

[0210]

[0251] FIGS. 28A and 28B are perspective views of a variant of an ablation device (2800) engaged with tissue (2860). In some variations, the ablation device (2800) can include a first catheter (not shown) and a second catheter (2830). In some variations, the ablation device (2800) can include a second catheter (2830) slidably disposed within the first catheter. The second catheter (2830) can include a return (2840) similar to the variant shown in FIGS. 26A and 26B and a dilator (2850). In some variations, the return (2840) can include a plurality of protrusions including a tissue engagement portion substantially parallel to the longitudinal axis of the second catheter (2830). The tissue (2860) can be configured to engage with the return (2840), as described in more detail herein.

[0211]

[0252] As used herein, the terms "about" and / or "substantially" when used with a numerical value and / or range generally refer to a numerical value and / or range close to the recited numerical value and / or range. In one example, the terms "about" and "substantially" can mean within ±10% of the recited value. For example, in some instances, "about 100 [units]" can mean within ±10% of 100 (e.g., 90 to 110). The terms "about" and "substantially" can be used interchangeably.

[0212]

[0253] The specific examples and descriptions in this specification are of an illustrative nature, and variations can be devised by those skilled in the art without departing from the scope of the invention, which is limited only by the appended claims based on the teachings herein.

[0213]

[0254] The above embodiments have been described in some detail by way of illustration and example for clarity and understanding, but it is clear that certain variations and improvements can be made and are also included within the scope of the appended claims. Further, it should be understood that the components and features of the elements described herein can be used in any combination, and the methods described herein can include all or some of the elements described herein. The description of a particular element or feature with respect to a particular figure should not be construed as limiting or suggesting that they cannot be used in combination with any of the other recited elements.

[0214]

[0255] In addition, any combination of two or more such features, structures, systems, articles, materials, kits, steps, and / or methods disclosed herein is included within the scope of the invention disclosed herein, provided such features, structures, systems, articles, materials, kits, steps, and / or methods are not mutually inconsistent. Further, some variations disclosed herein can be distinguishable from the prior art by clearly lacking one or more features, elements, and functions found in a reference or combination of references (i.e., the claims for such variations can include negative limitations).

[0215]

[0256] All references to publications or other documents, including but not limited to patents, patent applications, papers, web pages, books, etc., presented anywhere in this application are hereby incorporated by reference in their entirety into this specification. Further, all definitions defined and used in this specification should be understood to take precedence over the dictionary definitions of the defined terms, the definitions in the documents incorporated by reference, and / or the ordinary meanings.

Claims

1. A system for forming an anastomosis within the heart, comprising: a first catheter including an electrode for tissue resection; a second catheter slidably disposed within the first catheter, the second catheter including a retractor and an expander having a mating surface configured to engage the electrode; wherein the retractor is spaced proximally from the mating surface.

2. The system according to claim 1, wherein the retractor is disposed within the lumen of the electrode when the mating surface engages the electrode.

3. The system according to claim 1, wherein an outer diameter of the expander is smaller than an outer diameter of the electrode.

4. The system according to claim 1, wherein the second catheter defines a longitudinal axis, and the retractor includes at least one protrusion including a first portion and a second portion, the first portion being angled with respect to the second portion.

5. The system according to claim 4, wherein a ratio of a length of the first portion to a length of the second portion is in a range of 2:3 to 1:

5.

6. The system according to claim 4, wherein the second portion has a length in a range of 0.1 mm to 2 cm.

7. The system according to claim 1, wherein a length of the retractor is in a range of 0.1 mm to 5 cm.

8. The system according to claim 1, wherein the electrode and the mating surface are configured to compress tissue therebetween without piercing the tissue with a first predetermined force.

9. The system according to claim 1, wherein the expander includes a fluid port configured to discharge a contrast agent.

10. The system according to claim 1, wherein the first catheter includes a lumen for a contrast agent.

11. The system according to claim 1, wherein the electrode includes a fluid port configured to discharge a contrast agent.

12. The system according to claim 11, wherein a distal end of the electrode includes the fluid port.

13. The system according to claim 1, wherein the expander includes an echo-generating region including one or more recesses or protrusions having a diameter in a range of 5 μm to 100 μm.

14. The system according to claim 1, further comprising a first catheter actuator configured to deflect a distal portion of the first catheter, the first catheter actuator being electrically connected to the electrode.

15. ​ The system according to claim 1, wherein the mating surface defines a recess configured to receive the distal end of the electrode. **Claim 16** The system according to claim 15, wherein the electrode is configured to be electrically short-circuited when the electrode engages the recess of the mating surface. **Claim 17** The system according to claim 1, wherein the mating surface includes a conductive portion. **Claim 18** The system according to claim 1, wherein the proximal portion of the dilator is disposed within the lumen of the electrode when the mating surface engages the electrode. **Claim 19** The system according to claim 1, wherein the proximal portion of the dilator includes a first stepped portion having a first diameter and a second stepped portion having a second diameter greater than the first diameter, and the first stepped portion is proximal to the second stepped portion. **Claim 20** A system for forming an anastomosis within the heart, comprising: a first catheter including an electrode for tissue resection; a second catheter slidably disposed within the first catheter, the second catheter including a retractor and a dilator, wherein the retractor is housed within the lumen of the electrode when the dilator engages the electrode; and a system including the second catheter. **Claim 21** The system according to claim 8, wherein the dilator is configured to shear the tissue with a second predetermined force greater than the first predetermined force. **Claim 22** The system according to claim 21, wherein the first predetermined force is at most 25 N. **Claim 23** The system according to claim 21, wherein the second predetermined force is greater than 25 N. **Claim 24** The system according to claim 20, wherein the dilator includes a mating surface configured to limit proximal translation of the dilator relative to the electrode, and the retractor is housed within the lumen of the electrode when the mating surface seats within the electrode. **Claim 25** The system according to claim 1, further comprising an actuating mechanism coupled to the second catheter, the actuating mechanism being configured to select an amount of force for compressing tissue without cutting between the electrode and the dilator. **Claim 26** The system according to claim 25, wherein the actuating mechanism includes a screw mechanism including a plurality of predetermined stop members. **Claim 27** The system according to claim 25, wherein the force is selectable between 10 N and 20 N. **Claim 28** The return comprises a base connected to the dilator and a protrusion connected to the base, the maximum outer diameter of the return being smaller than the maximum outer diameter of the dilator, and the maximum outer diameter of the base being smaller than the maximum outer diameter of the return, the system according to claim 1.

29. The protrusion is disposed at a distance from the dilator by the base, the system according to claim 28.

30. The electrode is a non-invasive electrode and has a non-pointed distal edge, the system according to claim 28.

31. The base connects the protrusion to the second catheter, and the base spaces the protrusion proximally from the dilator, the system according to claim 28.

32. The proximal portion of the dilator includes a first stepped portion having a first diameter and a second stepped portion having a second diameter larger than the first diameter, the first stepped portion being proximal to the second stepped portion, the system according to claim 28.

33. The electrode is a non-invasive electrode, and the second stepped portion has a mating surface configured to engage the distal end of the non-invasive electrode, the system according to claim 32.

34. The electrode is a non-invasive electrode and is configured to receive an ablation waveform for excising compressed tissue, the system according to claim 28.

35. The tissue excised by the ablation waveform is disposed within the lumen of the non-invasive electrode after the non-invasive electrode receives the ablation waveform, the system according to claim 34.

36. The ablation waveform includes a biphasic waveform, the system according to claim 34.

37. The ablation waveform includes a first waveform followed by a second waveform, the first waveform including a first voltage, and the second waveform including a second voltage, and the first voltage being higher than the second voltage, the system according to claim 34.

38. The ablation waveform includes a current between 50 mA and 4 A, a voltage between 0.1 kV and 4.0 kV, and a frequency of up to 500 kHz, the system according to claim 34.

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