Device for delivery of pulsed electric fields in the treatment of cardiac tissue - Patent Application 20070122999

Abstract

To provide a device for delivery of pulsed electric fields in the treatment of cardiac tissue. [Solution] Devices, systems, and methods are provided for treating cardiac conditions, particularly arrhythmia occurrences, and more specifically atrial fibrillation, atrial flutter, ventricular tachycardia, and the like. The devices, systems, and methods deliver therapeutic pulsed electric field energy to provide tissue modification to portions of the heart, such as the entrances to the pulmonary veins, in the treatment of atrial fibrillation. Such tissue modification creates a conductive block within the tissue to prevent the transmission of abnormal electrical signals. Generally, the tissue modification system includes a dedicated catheter, a high-voltage waveform generator, and at least one distinct energy delivery algorithm. Exemplary embodiments of the dedicated catheter design are provided, including various delivery types, including local delivery, "one-shot" delivery, and various possible combinations.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. patent application Ser. No. 63 / 159,331, filed March 10, 2021, entitled "Devices for the Delivery of Pulsed Electric Fields in the Treatment of Cardiac Tissue," the disclosure of which is incorporated herein by reference in its entirety for all purposes. [Background technology]

[0002] Therapeutic energy can be applied to the heart and vascular system for the treatment of various conditions, including atherosclerosis (particularly in the prevention of restenosis after angioplasty) and arrhythmias such as atrial fibrillation. Atrial fibrillation is the most common sustained cardiac arrhythmia and significantly increases the risk of death in affected patients, particularly by causing stroke. In this phenomenon, the heart deviates from normal sinus rhythm due to the generation of erroneous electrical impulses. Atrial fibrillation is thought to be initiated in the myocardial sleeves of the pulmonary veins (PVs) due to the presence of automaticity in cells within the PV myocardial tissue. Pacemaker activity from these cells is thought to result in the formation of premature contractions that initiate atrial fibrillation. The PVs are also thought to be important in maintaining atrial fibrillation because the chaotic structure and electrophysiological properties of these vessels provide an environment in which atrial fibrillation can be perpetuated. Therefore, destruction or ablation of these aberrant pacemaker cells within the myocardial sheath of the PV has been targeted, and atrial fibrillation is often treated by delivering therapeutic energy to the pulmonary veins. However, due to reports of PV stenosis, this approach has traditionally been modified to target the PV sinus to achieve conduction block between the PV and the left atrium. The PV sinus encompasses the left atrial roof and posterior wall in addition to the pulmonary veins, and in the case of the right pulmonary vein sinus, a portion of the interatrial septum. In some cases, this technique exhibits a higher success rate and lower complication rate compared to pulmonary vein ostium isolation.

[0003] Thermal ablation therapy, particularly radiofrequency (RF) ablation, is currently the "gold standard" for treating symptomatic atrial fibrillation due to localized tissue necrosis. Typically, RF ablation is used to create a ring of ablation lesions around the ostium of each of the four pulmonary veins. RF current causes tissue desiccation by creating a localized region of heat that results in focal coagulation necrosis. The necrotic tissue acts as a conductive block, thereby electrically isolating the vein.

[0004] Despite improvements in re-establishing sinus rhythm using available methods, both success rates and safety remain limited. RF ablation continues to present several limitations, including long procedure times for performing pulmonary vein isolation using RF regional catheters, potential gaps in ablation patterns due to point-by-point ablation techniques using conventional RF catheters, difficulty in creating and confirming transmural ablation lesions, char and / or gas formation at the catheter tip-tissue interface due to high temperatures that can lead to thrombosis or embolism during ablation, and thermal damage to collateral extracardiac structures, including pulmonary vein stenosis, phrenic nerve injury, esophageal injury, atrioesophageal fistula, periesophageal vagus nerve injury, perforation, thromboembolic events, vascular complications, and acute coronary artery occlusion. These limitations are primarily due to the ongoing battle clinicians have faced balancing an effective therapeutic dose with inadequate energy delivery to extracardiac tissues.

[0005] Thus, while maintaining the technology in clinical practice, safer and more versatile methods of ablation of abnormal tissue are being used, including irreversible electroporation (IRE), a non-thermal therapy based on the irreversible permeabilization of cell membranes caused by specific short pulses of high-voltage energy. IRE is tissue-specific, induces apoptosis rather than necrosis, and has been shown to be safer for structures adjacent to the myocardium. However, to date, the success of these IRE methodologies has been uneven. In some cases, delivery of IRE energy has resulted in incomplete block of the abnormal electrical rhythm. This may be due to various factors, such as irregularities in treatment around the pulmonary vein, lack of transmural delivery of energy, or other defects in energy delivery. In either case, atrial fibrillation is not adequately treated, or atrial fibrillation recurs later. Therefore, improved atrial fibrillation treatments are desirable. Such treatments should be safe, effective, and result in reduced complications. At least some of these objectives will be met by the systems, devices, and methods described herein. Summary of the Invention [Means for solving the problem]

[0006]

[0006] Described herein are embodiments of devices, systems, and methods for treating target tissue, particularly cardiac tissue. Similarly, the present invention relates to the following numbered clauses:

[0007] 1. A device for delivering energy to cardiac tissue of a patient, comprising: a shaft having a proximal end and a distal end, the shaft having an outer diameter; an energy delivery body disposed along a distal end of the shaft, the energy delivery body being transitionable between a collapsed configuration and an expanded configuration, the expanded configuration having an outer diameter no greater than six times the outer diameter of the shaft, the energy delivery body being configured to be positioned against cardiac tissue in the expanded configuration to deliver energy to the cardiac tissue; A device comprising:

[0008]

[0008] 2. The device of claim 1, wherein the energy is pulsed electric field energy and the device is configured to deliver the pulsed electric field energy to cardiac tissue.

[0009]

[0009] 3. A device as described in any of the above claims, wherein the energy delivery body comprises a plurality of wires configured to deliver energy.

[0010] 4. The device of claim 3, wherein the plurality of wires comprises a plurality of splines.

[0011]

[0011] 5. A device as described in any of claims 3 to 4, wherein the plurality of wires are made of a shape memory material such that the energy delivery body is transitionable upon release from a sheath that restrains the plurality of wires, such that such release allows the plurality of wires to move toward an expanded configuration.

[0012]

[0012] 6. The device of claim 5, wherein the energy delivery body does not include a central shaft when in the expanded configuration.

[0013] 7. The device of claim 5, wherein the plurality of splines form a hollow round cage.

[0014] 8. The device of claim 3, wherein the plurality of wires comprises a mesh.

[0015] 9. The device of claim 3, wherein the plurality of wires comprises a plurality of loops.

[0016]

[0016] 10. A device as described in any one of claims 3 to 9, wherein the multiple wires are energizable in unison to function in a monopolar manner.

[0017]

[0017] 11. A device as described in any one of claims 3 to 10, wherein the plurality of wires have convex distal surfaces.

[0018]

[0018] 12. A device described in any of claims 3 to 11, wherein the energy delivery body includes a distal tip configured to deliver energy.

[0019] 13. The device of claim 12, wherein the distal tip and the plurality of wires are energizable in unison to function in a monopolar manner.

[0020]

[0020] 14. A device as described in any one of claims 3 to 13, wherein the proximal portions of the multiple wires are insulated to direct energy distally.

[0021]

[0021] 15. A device as described in any of the above claims, further comprising a plurality of irrigation ports, the device being configured to direct fluid through the irrigation ports to create turbulent fluid flow within the energy delivery body.

[0022]

[0022] 16. The device of claim 15, wherein the multiple irrigation ports are disposed near the proximal end of the energy delivery body.

[0023] 17. A device as described in any one of claims 15 to 16, further comprising one or more irrigation lumens directing fluid through a plurality of irrigation ports.

[0024]

[0024] 18. The device of claim 17, wherein the one or more irrigation lumens are less than the multiple irrigation ports.

[0025]

[0025] 19. A device as described in any of the above claims, wherein the expanded configuration has an outer diameter that is 3 to 6 times the outer diameter of the shaft.

[0026]

[0026] 20. A device as described in any of the above claims, wherein the expanded configuration has an outer diameter of 8 to 15 mm.

[0027]

[0027] 21. A device as described in any of the above claims, wherein the energy delivery body includes a sensing electrode.

[0028] 22. The device of claim 21, wherein the sensing electrodes are positioned to avoid contact with cardiac tissue.

[0029]

[0029] 23. The device of claim 22, wherein the energy delivery body comprises a plurality of splines forming a round cage, and the sensing electrode is disposed within the round cage.

[0030]

[0030] 24. A device as described in any of the above claims, wherein the shaft includes one or more ring electrodes.

[0031]

[0031] 25. A device as described in any of the above claims, further comprising one or more electrodes in communication with an electrophysiological mapping system.

[0032]

[0032] 26. A device as described in any of the above claims, further comprising a steering mechanism configured to bend the energy delivery body relative to the shaft.

[0033]

[0033] 27. A device as described in any of the above claims, further comprising a steering mechanism configured to bend the distal end of the shaft away from its longitudinal axis.

[0034] 28. A device for treating cardiac tissue of a patient, comprising: a shaft having a proximal end and a distal end; an energy delivery body disposed along a distal end of the shaft, the energy delivery body configured to be positioned relative to cardiac tissue and electrically coupleable with the generator to deliver pulsed electric field energy to the cardiac tissue; A device comprising:

[0035]

[0035] 29. A catheter as described in claim 28, wherein the energy delivery body comprises one or more loops formed from wire.

[0036]

[0036] 30. A catheter as described in any of claims 28 to 29, wherein at least one electrode comprises one or more loops arranged to form a continuous edge configured to contact cardiac tissue.

[0037]

[0037] 31. A catheter as described in claim 30, wherein the continuous edge has a closed shape with a diameter of 8 to 15 mm.

[0038]

[0038] 32. A catheter as described in claim 30, wherein the continuous edge has a closed shape with a diameter smaller than the inner diameter of the pulmonary vein.

[0039]

[0039] 33. A catheter as described in claim 30, wherein the continuous edge has a closed shape configured to mate with the opening of the pulmonary vein to create a continuous lesion around the opening of the pulmonary vein.

[0040]

[0040] 34. A catheter as described in any of claims 30 to 33, wherein the continuous edge forms a closed shape having an adjustable diameter.

[0041]

[0041] 35. A catheter as described in any of claims 30 to 34, further comprising an electrode arranged along the distal end of the shaft so that the continuous edge can be positioned against the cardiac tissue and contact the cardiac tissue when pressure is applied.

[0042] 36. A catheter as described in claim 35, wherein the electrodes are disposed along the distal end of the shaft so as to release contact with the cardiac tissue when pressure is released from the continuous edge.

[0043]

[0043] 37. A catheter as described in any of claims 28 to 36, wherein at least a portion of the energy delivery body is configured to bend when the energy delivery body is positioned against cardiac tissue pressure and pressure is applied.

[0044]

[0044] 38. A catheter as described in claim 28, wherein the energy delivery body comprises one or more loops forming a convex distal surface.

[0045]

[0045] 39. A catheter as described in claim 38, wherein the convex distal surface is configured to seat against the inlet of a pulmonary vein.

[0046]

[0046] 40. The catheter of claim 39, wherein at least a portion of the convex distal surface is configured to seat within a pulmonary vein.

[0047]

[0047] 41. A catheter as described in claim 28, wherein the energy delivery body comprises one or more loops forming a concave distal surface.

[0048]

[0048] 42. The catheter of claim 41, wherein the one or more loops comprise two pairs of loops, each pair of loops comprising a smaller loop within a larger loop.

[0049] 43. A catheter as described in claim 42, wherein the shaft has a longitudinal axis and each of the two pairs of loops extends in opposite directions from the longitudinal axis.

[0050]

[0050] 44. A catheter as described in claim 28, wherein the energy delivery body comprises a single paddle-shaped electrode having a narrower shape near the shaft and a wider shape extending away from the shaft.

[0051] 45. The catheter of claim 44, wherein the wider shape has a hammerhead shape.

[0052]

[0052] 46. A catheter as described in claim 28, wherein the energy delivery body is transitionable between a collapsed configuration and an expanded configuration, the expanded configuration having an outer diameter that is no greater than six times the outer diameter of the shaft, and the energy delivery body is configured to be positioned against cardiac tissue in the expanded configuration to deliver energy to the cardiac tissue.

[0053] 47. A device for delivering energy to cardiac tissue of a patient, comprising: a shaft having a proximal end and a distal end; an energy delivery body disposed along a distal end of the shaft, the energy delivery body comprising a plurality of shape memory splines and transitionable between a collapsed configuration and an expanded configuration, wherein in the expanded configuration the plurality of shape memory splines form a convex distal surface positionable against cardiac tissue to deliver energy to the cardiac tissue; A device comprising:

[0054]

[0054] 48. The device of claim 47, wherein the plurality of shape memory splines, in the expanded configuration, form a rounded cage having a convex distal surface.

[0055]

[0055] 49. The device of claim 48, wherein the round cage is supported only by a plurality of splines.

[0056]

[0056] 50. The device of claim 49, wherein the energy delivery body includes a distal tip electrode, and wherein the plurality of splines support a tip electrode wire extending from the distal tip electrode to the shaft, which is otherwise hollow.

[0057]

[0057] 51. A device as described in any of claims 48 to 50, wherein the round cage is flexible so as to deform when positioned against cardiac tissue.

[0058]

[0058] 52. A device as described in any of claims 48 to 51, wherein the round cage is flexible so as to at least partially flatten when positioned against cardiac tissue.

[0059]

[0059] 53. A device as described in any of claims 48 to 52, wherein the convex distal surface is configured to have a footprint of 8 to 15 mm when positioned against cardiac tissue to deliver energy to the cardiac tissue.

[0060]

[0060] 54. A device as described in any of the above claims, wherein multiple splines are energizable in unison to function in a unipolar manner.

[0061]

[0061] 55. A device as described in any of the above claims, wherein the energy delivery body includes a distal tip electrode arranged along the convex distal surface.

[0062]

[0062] 56. The device of claim 55, wherein the distal tip electrodes are independently energizable.

[0063]

[0063] 57. A device as described in any of the above claims, wherein at least a portion of the energy delivery body is insulated to direct energy through the convex distal surface.

[0064]

[0064] 58. A device as described in any of the above claims, further comprising at least one irrigation lumen and a plurality of irrigation ports.

[0065]

[0065] 59. The device of claim 58, wherein the at least one irrigation lumen comprises fewer irrigation lumens than the plurality of irrigation ports.

[0066]

[0066] 60. The device of claim 48, wherein the energy delivery body is electrically connectable to the generator to deliver pulsed electric field energy to cardiac tissue.

[0067] 61. A system for delivering energy to cardiac tissue of a patient, comprising: A treatment catheter, a shaft having a proximal end and a distal end, the shaft having an outer diameter; an energy delivery body disposed along a distal end of the shaft, the energy delivery body being transitionable between a collapsed configuration and an expanded configuration, the expanded configuration having an outer diameter no greater than six times the outer diameter of the shaft, the energy delivery body being configured to be positioned against cardiac tissue in the expanded configuration to deliver energy to the cardiac tissue; a treatment catheter comprising: a generator electrically connectable to the treatment catheter, the generator including at least one energy delivery algorithm configured to provide an electrical signal of pulsed electric field energy deliverable through the energy delivery body; A system comprising:

[0068]

[0068] 62. The system of claim 61, wherein the pulsed electric field energy is below the threshold for inducing coagulative thermal damage.

[0069] 63. A system for treating cardiac tissue of a patient, comprising: A therapeutic device comprising: a shaft having a proximal end and a distal end; an energy delivery body disposed along a distal end of the shaft, the energy delivery body configured to be positioned relative to cardiac tissue and electrically coupleable with the generator to deliver pulsed electric field energy to the cardiac tissue; a treatment device comprising: a generator electrically connectable to the treatment catheter, the generator including at least one energy delivery algorithm configured to provide an electrical signal of pulsed electric field energy deliverable through the energy delivery body; A system comprising:

[0070]

[0070] 64. The system of claim 63, wherein the pulsed electric field energy is below the threshold for inducing coagulative thermal damage.

[0071] 65. A system for delivering energy to cardiac tissue of a patient, comprising: A treatment catheter, a shaft having a proximal end and a distal end; an energy delivery body disposed along a distal end of the shaft, the energy delivery body comprising a plurality of shape memory splines and transitionable between a collapsed configuration and an expanded configuration, wherein in the expanded configuration the plurality of shape memory splines form a convex distal surface positionable against cardiac tissue to deliver energy to the cardiac tissue; a treatment catheter comprising: a generator electrically connectable to the treatment catheter, the generator including at least one energy delivery algorithm configured to provide an electrical signal of pulsed electric field energy deliverable through the energy delivery body; A system comprising:

[0072]

[0072] 66. The system of claim 65, wherein the pulsed electric field energy is below the threshold for inducing coagulative thermal damage.

[0073] 67. A method of treating a patient, comprising: advancing a distal end of a catheter into a patient's heart, the catheter having an energy delivery element disposed along the distal end; positioning a return electrode remote from the distal end of the catheter; Positioning at least a portion of the energy delivery body at a first location along a region of cardiac tissue; delivering pulsed electric field energy unipolarly through at least one electrode such that the pulsed electric field energy is conducted through cardiac tissue to a return electrode; repeatedly repositioning at least a portion of the energy delivery body to one or more additional locations along the region of cardiac tissue to create a continuous lesion; A method comprising:

[0074]

[0074] 68. The method of claim 67, wherein the first location and the one or more additional locations create a closed shape around a pulmonary vein of the heart.

[0075]

[0075] 69. The method of claim 67, wherein the continuous lesion has a depth sufficient to block electrical conduction between the pulmonary vein and the remainder of the heart.

[0076]

[0076] 70. The method of claim 68, wherein the first location and the one or more additional locations create a linear shape having a depth sufficient to block electrical conduction.

[0077]

[0077] 71. The method of claim 67, wherein the energy delivery body comprises one or more loops arranged to form a continuous edge, and positioning at least a portion of the energy delivery body comprises positioning the continuous edge.

[0078]

[0078] 72. The method of claim 67, wherein the energy delivery body comprises one or more loops formed from a wire.

[0079]

[0079] These and other embodiments are described in further detail in the following description in conjunction with the accompanying drawings. The present invention provides, for example, the following items. (Item 1) 1. A device for delivering energy to cardiac tissue of a patient, comprising: a shaft having a proximal end and a distal end and having an outer diameter; an energy delivery body disposed along the distal end of the shaft, the energy delivery body being transitional between a collapsed configuration and an expanded configuration, the expanded configuration having an outer diameter no greater than six times the outer diameter of the shaft, the energy delivery body being configured to be positioned against the cardiac tissue in the expanded configuration to deliver energy to the cardiac tissue; A device comprising: (Item 2) the energy is pulsed electric field energy; Item 10. The device of item 1, wherein the device is configured to deliver the pulsed electric field energy to the cardiac tissue. (Item 3) 3. The device of claim 1 or 2, wherein the energy delivery body comprises a plurality of wires configured to deliver the energy. (Item 4) Item 4. The device of item 3, wherein the plurality of wires comprises a plurality of splines. (Item 5) 5. The device of claim 3 or 4, wherein the plurality of wires are made of a shape memory material such that the energy delivery entity is transitionable upon release from a sheath that constrains the plurality of wires, such that such release allows the plurality of wires to move toward the expanded configuration. (Item 6) 6. The device of claim 5, wherein the energy delivery body does not include a central shaft when in the expanded configuration. (Item 7) Item 6. The device of item 5, wherein the plurality of splines form a hollow round cage. (Item 8) Item 4. The device of item 3, wherein the plurality of wires comprises a mesh. (Item 9) Item 4. The device of item 3, wherein the plurality of wires comprises a plurality of loops. (Item 10) 10. The device of any one of items 3 to 9, wherein the multiple wires are energizable in unison to function in a monopolar manner. (Item 11) 11. The device of any one of items 3 to 10, wherein the plurality of wires have a convex distal surface. (Item 12) 12. The device of any one of claims 3 to 11, wherein the energy delivery body includes a distal tip configured to deliver the energy. (Item 13) Item 13. The device of item 12, wherein the distal tip and the plurality of wires are energizable in unison to function in a monopolar manner. (Item 14) 14. The device of any one of claims 3 to 13, wherein a proximal portion of the plurality of wires is insulated to direct the energy distally. (Item 15) further comprising a plurality of irrigation ports; 15. The device of any one of items 1 to 14, wherein the device is configured to direct fluid through the irrigation port to create turbulent flow of the fluid within the energy delivery body. (Item 16) Item 16. The device of item 15, wherein the plurality of irrigation ports are disposed near the proximal end of the energy delivery body. (Item 17) 17. The device of claim 15 or 16, further comprising one or more irrigation lumens directing the fluid through the plurality of irrigation ports. (Item 18) Item 18. The device of item 17, wherein the one or more irrigation lumens are fewer than the plurality of irrigation ports. (Item 19) 19. The device of any one of items 1 to 18, wherein the expanded configuration has an outer diameter that is 3 to 6 times the outer diameter of the shaft. (Item 20) 20. The device of any one of items 1 to 19, wherein the expanded configuration has an outer diameter of 8 to 15 mm. (Item 21) 21. The device of any one of claims 1 to 20, wherein the energy delivery body includes a sensing electrode. (Item 22) 22. The device of claim 21, wherein the sensing electrodes are positioned to avoid contact with the cardiac tissue. (Item 23) the energy delivery body comprises a plurality of splines forming a rounded cage; Item 23. The device of item 22, wherein the sensing electrode is disposed within the round cage. (Item 24) 24. The device of any one of items 1 to 23, wherein the shaft comprises one or more ring electrodes. (Item 25) 25. The device of any one of items 1 to 24, further comprising one or more electrodes in communication with an electrophysiological mapping system. (Item 26) 26. The device of any one of items 1 to 25, further comprising a steering mechanism configured to bend the energy delivery body relative to the shaft. (Item 27) 27. The device of any one of items 1 to 26, further comprising a steering mechanism configured to bend the distal end of the shaft away from its longitudinal axis. (Item 28) 1. A device for delivering energy to cardiac tissue of a patient, comprising: a shaft having a proximal end and a distal end; an energy delivery body disposed along the distal end of the shaft, the energy delivery body comprising a plurality of shape memory splines and transitionable between a collapsed configuration and an expanded configuration, wherein in the expanded configuration the plurality of shape memory splines form a convex distal surface positionable against the cardiac tissue to deliver energy to the cardiac tissue; A device comprising: (Item 29) Item 29. The device of item 28, wherein the plurality of shape memory splines form a rounded cage having the convex distal surface in the expanded configuration. (Item 30) 30. The device of claim 29, wherein the round cage is supported solely by the plurality of splines. (Item 31) the energy delivery body includes a distal tip electrode; Item 31. The device of item 30, wherein the plurality of splines support a tip electrode wire extending from the distal tip electrode to the shaft, which is otherwise hollow. (Item 32) 32. The device of any one of items 29 to 31, wherein the round cage is flexible so as to deform when positioned against the cardiac tissue. (Item 33) 33. The device of any one of items 29 to 32, wherein the round cage is flexible so as to at least partially flatten when positioned against the cardiac tissue. (Item 34) 34. The device of any one of items 28 to 33, wherein the convex distal surface is configured to have a footprint of 8 to 15 mm when positioned against the cardiac tissue to deliver energy to the cardiac tissue. (Item 35) 35. The device of any one of claims 1 to 34, wherein the plurality of splines are energizable in unison to function in a unipolar manner. (Item 36) 36. A device described in any one of items 1 to 35, wherein the energy delivery body includes a distal tip electrode disposed along the convex distal surface. (Item 37) Item 37. The device of item 36, wherein the distal tip electrodes are independently energizable. (Item 38) 38. The device of any one of claims 1 to 37, wherein at least a portion of the energy delivery body is insulated to direct the energy through the convex distal surface. (Item 39) 39. The device of any one of items 1 to 38, further comprising at least one irrigation lumen and a plurality of irrigation ports. (Item 40) 40. The device of claim 39, wherein the at least one irrigation lumen comprises fewer irrigation lumens than the plurality of irrigation ports. (Item 41) 30. The device of claim 29, wherein the energy delivery body is electrically coupled to a generator to deliver pulsed electric field energy to the cardiac tissue. (Item 42) 1. A system for delivering energy to cardiac tissue of a patient, comprising: A treatment catheter, a shaft having a proximal end and a distal end and having an outer diameter; an energy delivery body disposed along the distal end of the shaft, the energy delivery body being transitional between a collapsed configuration and an expanded configuration, the expanded configuration having an outer diameter no greater than six times the outer diameter of the shaft, the energy delivery body being configured to be positioned against the cardiac tissue in the expanded configuration to deliver energy to the cardiac tissue; a treatment catheter comprising: a generator electrically connectable to the treatment catheter, the generator including at least one energy delivery algorithm configured to provide an electrical signal of pulsed electric field energy deliverable through the energy delivery body; A system comprising: (Item 43) 43. The system of claim 42, wherein the pulsed electric field energy is below the threshold for inducing coagulative thermal damage. (Item 44) 1. A system for treating cardiac tissue of a patient, comprising: A therapeutic device comprising: a shaft having a proximal end and a distal end; an energy delivery body disposed along the distal end of the shaft, the energy delivery body configured to be positioned relative to the cardiac tissue and electrically coupleable with a generator to deliver pulsed electric field energy to the cardiac tissue; and a treatment device comprising: a generator electrically connectable to the treatment catheter, the generator including at least one energy delivery algorithm configured to provide an electrical signal of pulsed electric field energy deliverable through the energy delivery body; A system comprising: (Item 45) 45. The system of claim 44, wherein the pulsed electric field energy is below the threshold for inducing coagulative thermal damage. (Item 46) 1. A system for delivering energy to cardiac tissue of a patient, comprising: A treatment catheter, a shaft having a proximal end and a distal end; an energy delivery body disposed along a distal end of the shaft, the energy delivery body comprising a plurality of shape memory splines and transitionable between a collapsed configuration and an expanded configuration, wherein in the expanded configuration the plurality of shape memory splines form a convex distal surface positionable against the cardiac tissue to deliver energy to the cardiac tissue; a treatment catheter comprising: a generator electrically connectable to the treatment catheter, the generator including at least one energy delivery algorithm configured to provide an electrical signal of pulsed electric field energy deliverable through the energy delivery body; A system comprising: (Item 47) 47. The system of claim 46, wherein the pulsed electric field energy is below the threshold for inducing coagulative thermal damage.

[0080] (Incorporated by reference)

[0080] All publications, patents, and patent applications mentioned in this specification are hereby incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. [Brief explanation of the drawings]

[0081] In the drawings, which are not necessarily drawn to scale, like numerals may describe like components in different views. Like numerals with different subscripts may represent different instances of like components. The drawings generally illustrate, by way of example, but not by way of limitation, various embodiments discussed in this document.

[0082] [Figure 1]

[0082] One embodiment of a tissue modification system is illustrated. [Figure 2A]

[0083] 1 illustrates an embodiment of a treatment catheter configured to deliver local therapy. [Figure 2B]

[0083] An embodiment of a treatment catheter configured to deliver local therapy is illustrated. [Figure 3]

[0084] A portion of the heart is illustrated showing cross-sectional views of the right and left atria with treatment catheters positioned therein. [Figure 4]

[0085] 10 illustrates repeated application of energy in a point-by-point manner around the left inferior pulmonary vein using a treatment catheter to create a circular treatment zone. [Figure 5]

[0086] 1 illustrates one embodiment of a waveform of a signal defined by an energy delivery algorithm. [Figure 6]

[0087] 1 illustrates an exemplary waveform defined by an energy delivery algorithm, the waveform having a voltage imbalance. [Figure 7]

[0088] 10 illustrates further examples of waveforms with unequal voltages. [Figure 8]

[0089] 10 illustrates a further example of a waveform having unequal pulse widths. [Figure 9]

[0090] 1 illustrates an exemplary waveform defined by another energy delivery algorithm, where the waveform is monophasic, a special case of imbalance where only the positive or only the negative portion of the waveform is present. [Figure 10]

[0091] 10 illustrates a further example of a waveform having monophasic pulses. [Figure 11]

[0092] 1 illustrates an example of a waveform having a phase imbalance. [Figure 12]

[0093] 1 illustrates an exemplary waveform defined by another energy delivery algorithm, where the pulses are sinusoidal in shape rather than square. [Figure 13A]

[0094] 1 illustrates an embodiment of a treatment catheter configured for localized delivery, optionally covering a larger area of ​​tissue than the cylindrically shaped delivery electrodes typically found in conventional RF catheters. [Figure 13B]

[0094] An embodiment of a treatment catheter configured for local delivery is illustrated, which optionally covers a larger area of ​​tissue than the cylindrically shaped delivery electrodes typically found in conventional RF catheters. [Figure 13C]

[0094] An embodiment of a treatment catheter configured for local delivery is illustrated, which optionally covers a larger area of ​​tissue than the cylindrically shaped delivery electrodes typically found in conventional RF catheters. [Figure 14A]

[0095] 13A-13C illustrate the delivery of the catheter embodiment of FIG. [Figure 14B]

[0095] Illustrates delivery of the catheter embodiment of Figures 13A to 13C. [Figure 14C]

[0095] Illustrates delivery of the catheter embodiment of Figures 13A to 13C. [Figure 14D]

[0095] Illustrates delivery of the catheter embodiment of Figures 13A to 13C. [Figure 15]

[0096] 1 provides a visual illustration of exemplary end effectors adjacent to one another in contact with tissue. [Figure 16]

[0097] 1 illustrates another embodiment of a treatment catheter configured for local delivery or one-shot therapy, optionally covering a larger area of ​​tissue than the cylindrically shaped delivery electrodes typically found in conventional RF catheters. [Figure 17]

[0098] 17 illustrates the embodiment of FIG. 16 positioned relative to a laboratory benchtop model of the entrance to the pulmonary veins. [Figure 18A]

[0099] 1 illustrates a delivery electrode deployed from a delivery sheath such that the electrode extends generally perpendicular to the longitudinal axis of the delivery sheath. [Figure 18B]

[0099] The delivery electrodes are shown deployed from the delivery sheath so that the electrodes extend approximately perpendicular to the longitudinal axis of the delivery sheath. [Figure 19]

[0100] 18A to 18B illustrate further extension of the electrode from the sheath, which allows the petal-shaped electrode to curve downward so that the outer edge of the electrode is disposed proximal to the distal tip of the sheath. [Figure 20]

[0101] A further development of the electrode in Figures 18A-18B is shown that exaggerates this shape, allowing the sides to bend or curve even more. [Figure 21]

[0102] 1 illustrates an embodiment of a treatment catheter configured for localized delivery rather than one-shot or combination delivery. [Figure 22]

[0103] 1 illustrates an embodiment of a treatment catheter in which the delivery electrode comprises multiple trowel-shaped electrodes extending from the shaft. [Figure 23]

[0104] 23 illustrates a side view of an embodiment of a treatment catheter similar to that of FIGS. 21-22. [Figure 24]

[0105] 1 shows another embodiment of a treatment catheter with multiple trowel-shaped electrodes extending from a shaft, where the proximal end is free and the distal end is attached to the catheter by a support. [Figure 25]

[0106] 1 illustrates an embodiment of a treatment catheter in which the delivery electrode comprises a single petal, paddle, or loop shaped electrode with a narrower shape near the shaft and a larger, wider shape extending away from the shaft. [Figure 26A]

[0107] 1 illustrates one embodiment of a treatment catheter having paddle-shaped delivery electrodes, the delivery electrode comprising a single hammerhead paddle-shaped electrode having a narrower shape near the shaft and a wider hammerhead shape distal to the shaft. [Figure 26B]

[0107] One embodiment of a treatment catheter having a paddle-shaped delivery electrode is illustrated, in which the delivery electrode comprises a single hammerhead paddle-shaped electrode having a narrower shape near the shaft and a wider hammerhead shape distal to the shaft. [Figure 27]

[0108] 1 illustrates another embodiment of a treatment catheter. [Figure 28]

[0108] Another embodiment of a treatment catheter is illustrated. [Figure 29]

[0108] Another embodiment of a treatment catheter is illustrated. [Figure 30]

[0108] Another embodiment of a treatment catheter is illustrated. [Figure 31A]

[0109] 1 illustrates an embodiment of a treatment catheter configured for one-shot delivery rather than local delivery. [Figure 31B]

[0109] An embodiment of a treatment catheter configured for one-shot delivery rather than local delivery is illustrated. [Figure 31C]

[0109] An embodiment of a treatment catheter configured for one-shot delivery rather than local delivery is illustrated. [Figure 31D]

[0109] An embodiment of a treatment catheter configured for one-shot delivery rather than local delivery is illustrated. [Figure 32A]

[0110] 1 illustrates another embodiment of a treatment catheter. [Figure 32B]

[0110] Another embodiment of a treatment catheter is illustrated. [Figure 32C]

[0110] Another embodiment of a treatment catheter is illustrated. [Figure 33A]

[0111] 1 illustrates yet another embodiment of a treatment catheter. [Figure 33B]

[0111] Yet another embodiment of a treatment catheter is illustrated. [Figure 33C]

[0111] Yet another embodiment of a treatment catheter is illustrated. [Figure 33D]

[0111] Yet another embodiment of a treatment catheter is illustrated. [Figure 34]

[0112] 1 illustrates an embodiment of a treatment catheter having a multi-spline energy delivery body. [Figure 35]

[0113] 35 provides a side view of the treatment catheter embodiment of FIG. 34. [Figure 36]

[0114] 36 illustrates a bottom view of the treatment catheter of FIGS. 34-35. FIG. [Figure 37]

[0115] 35 provides another perspective view of the embodiment of FIG. 34. [Figure 38]

[0116] 35 provides an enlarged view of a portion within the distal end of the shaft of the treatment catheter of FIG. 34. [Figure 39A]

[0117] 35 provides an exploded view of the elements comprising this embodiment of the treatment catheter of FIG. 34. [Figure 39B]

[0118] The treatment catheter of Figure 39A is shown in an undeployed state. DETAILED DESCRIPTION OF THE INVENTION

[0083]

[0119] Devices, systems, and methods are provided for treating cardiac conditions, particularly arrhythmias, such as atrial fibrillation, atrial flutter, ventricular tachycardia, Wolff-Parkinson-White syndrome, and / or atrioventricular nodal reentrant tachycardia. The devices, systems, and methods deliver therapeutic energy to provide tissue modification to portions of the heart, such as the entrances to the pulmonary veins, in the treatment of atrial fibrillation. Specific anatomical sites targeted include the superior vena cava, inferior vena cava, right pulmonary veins, left pulmonary veins, right atrium, right atrial appendage, left atrium, left atrial appendage, right ventricle, left ventricle, right ventricular outflow tract, left ventricular outflow tract, interventricular septum, left ventricular apex, areas of myocardial scar, myocardial infarction border zone, myocardial infarction channel, ventricular endocardium, ventricular epicardium, papillary muscles, and the Purkinje system. Treatments may be delivered at isolated sites or over a series of related treatments. Treatment types include left atrial canopy lines, left atrial posterior / inferior lines, posterior wall separation, lateral mitral isthmus lines, septal mitral isthmus line creation, left atrial appendage, right tricuspid-inferior vena cava isthmus (CTI), pulmonary vein isolation, superior vena cava isolation, Marshall's vein, lesion creation using complex split atrial potentials (CFAEs), lesion creation using local impulse and rotor modulation (FIRM), and targeted ganglion ablation. Such tissue modification creates a conductive block within the tissue to prevent the transmission of abnormal electrical signals. The devices, systems, and methods are typically used in an electrophysiology laboratory or controlled operating room equipped with fluoroscopy and advanced ECG recording and monitoring capabilities. An electrophysiologist (EP) is typically the intended primary user of the system. The electrophysiologist will be assisted by trained nurses, technicians, and potentially other electrophysiologist staff. Generally, the tissue modification system includes a dedicated catheter, a high-voltage waveform generator, and at least one distinct energy delivery algorithm. Additional accessories and equipment may be utilized. Exemplary embodiments of dedicated catheter designs are provided herein, including various delivery types, including local delivery, "one-shot" delivery, and various possible combinations. For illustrative purposes, simplified designs are provided when describing the overall system. Such simplified designs provide monopolar local therapy.However, it will be appreciated that various other embodiments are also provided.

[0084]

[0120] FIG. 1 illustrates one embodiment of a tissue modification system 100 comprising a treatment catheter 102, a mapping catheter 104, a return electrode 106, a waveform generator 108, and an external cardiac monitor 110. In this embodiment, the heart is accessed via the right femoral vein FV by a suitable access procedure, such as the Seldinger technique. Typically, a sheath 112, which acts as a conduit, is inserted into the femoral vein FV, through which various catheters and / or tools, including the treatment catheter 102 and the mapping catheter 104, may be advanced. It will be appreciated that in some embodiments, the treatment catheter 102 and the mapping catheter 104 are combined into a single device. As illustrated in FIG. 1 , the distal ends of the catheters 102 and 104 are advanced through the inferior vena cava, through the right atrium, through a transseptal puncture, and into the left atrium to access the entrance to the pulmonary veins. The mapping catheter 104 is used to perform cardiac mapping, which refers to the process of identifying the temporal and spatial distribution of myocardial electrical potentials during specific heart rhythms. Cardiac mapping during abnormal cardiac rhythms aims to elucidate the mechanism of the cardiac rhythm, describe excitation propagation from initiation to completion within a region of interest, and identify sites of origin or critical areas of conduction that can serve as targets for therapy. Once the desired treatment location is identified, a therapy catheter 102 is utilized to deliver the therapy energy.

[0085]

[0121] In this embodiment, the proximal end of the treatment catheter 102 is electrically connected to a waveform generator 108, which is software controlled with a regulated energy output that creates high frequency short duration energy that is delivered to the catheter 102. It will be understood that in various embodiments, the output is controlled or modified to achieve a desired voltage, current, or combination thereof. In this embodiment, the proximal end of the mapping catheter 104 is also electrically connected to the waveform generator 108, and the electronics that perform the mapping procedure are contained within the generator 108. However, it will be understood that the mapping catheter 104 may alternatively be connected to a separate external device capable of providing a mapping procedure, such as an electroanatomical mapping (EAM) system (e.g., the CARTO® system by Biosense Webster / Johnson & Johnson, the EnSite™ system by St. Jude Medical / Abbott, the KODEX-EPD system by Philips, or the Rhythmia HDX™ system by Boston Scientific). Similarly, in some embodiments, a separate mapping catheter 104 is not used, but rather the mapping functionality is incorporated into the catheter 102 .

[0086]

[0122] In this embodiment, the generator 108 is connected to an external cardiac monitor 110 to enable energy delivery coordinated with cardiac signals sensed from the patient P. The generator synchronizes the energy output to the patient's cardiac rhythm. The cardiac monitor provides a trigger signal to the generator 108 upon detecting the patient's cardiac cycle R wave. This trigger signal, along with the generator's algorithms, ensures that energy delivery is synchronized with the patient's cardiac cycle, reducing the likelihood of arrhythmias due to energy delivery. Typically, a foot switch allows the user to initiate and control the delivery of the energy output. A generator user interface (UI) provides the user with both auditory and visual information regarding energy delivery and generator operating status.

[0087]

[0123] In this embodiment, the treatment catheter 102 is designed to be monopolar, with the distal end of the catheter 108 having a delivery electrode 122 and the return electrode 106 positioned on the skin outside the body, typically on the thigh, lower back, or back. FIG. 2A illustrates one embodiment of a treatment catheter 102 configured to deliver local therapy. In this embodiment, the catheter 102 comprises an elongated shaft 120 having a delivery electrode 122 near its distal end 124 and a handle 126 near its proximal end 128. The delivery electrode 122 is shown as a "solid tip" electrode and has a cylindrical shape with a distal face having a continuous surface. In some embodiments, the cylindrical shape has a diameter of approximately 2-3 mm across its distal face and a length along the shaft 120 of approximately 1 mm, 2 mm, 1-2 mm, 3 mm, 4 mm, 3-4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc. It will be understood that such electrodes are typically hollow but are referred to as solid due to their appearance. In some embodiments, the catheter 102 has an overall length of 50-150 cm, preferably 100-125 cm, and more preferably 110-115 cm. Similarly, in some embodiments, the catheter has an outer diameter of 7 Fr, 3-15 Fr, preferably 4-12 Fr, and more preferably 7-8.5 Fr. It will be appreciated that in some embodiments, the shaft 120 has a deflectable end portion 121, which may optionally have a length of 50-105 mm to provide a curve with a diameter ranging from approximately 15-55 mm. Deflection may be achieved by various mechanisms, including pull wires extending to the handle 126. The handle 126 is thus used to manipulate the catheter 102, particularly to steer the distal end 124 during delivery and treatment. Energy is provided to the catheter 102, and thus the delivery electrode 122, via a cable 130 connectable to a generator 108.

[0088]

[0124] A pulsed electric field (PEF) is provided by generator 108 and delivered to the tissue through delivery electrodes 122 placed on or near the target tissue region. It will be appreciated that in some embodiments, delivery electrodes 122 are positioned in contact with a conductive substance, which is also in contact with the target tissue. Such a solution may include an isotonic or hypertonic solution. These solutions may further include adjuvant substances, such as chemotherapy or calcium, to further enhance therapeutic efficacy, both for localized treatment and for potential localized invasion of the targeted tissue type. High-voltage, short-duration, biphasic electrical pulses are then delivered near the target tissue through electrodes 122. These electrical pulses are provided by at least one energy delivery algorithm 152. In some embodiments, each energy delivery algorithm 152 defines a signal having a waveform comprising a series of energy packets, each comprising a series of high-voltage pulses. In such embodiments, algorithm 152 specifies parameters of the signal, such as the energy amplitude (e.g., voltage) and duration of the applied energy, which may be comprised of the number of packets, the number of pulses within the packet, the fundamental frequency of the pulse sequence, and the like. Additional parameters may include the switching time between polarities in a biphasic pulse, the dead time between biphasic cycles, and the pause time between packets, which are described in more detail in later sections. There may be a fixed pause period between packets, or the packets may be synchronized to the cardiac cycle and therefore variable depending on the patient's heart rate. There may be a deliberately varying pause period algorithm, or no pause period may be applied between packets. Feedback loops based on sensor information and automatic shutoff specifications, and / or the like may be included.

[0089]

[0125] It will be appreciated that in various embodiments, the treatment catheter 102 includes various specialized features. For example, in some embodiments, the catheter 102 includes a mechanism for real-time measurement of the contact force applied by the catheter tip to the patient's heart wall during the procedure. In some embodiments, this mechanism comprises a three-axis optical force sensor included in the shaft 120 that utilizes white light interferometry. By monitoring and modifying the applied force throughout the procedure, the user can better control the catheter 102 to create more consistent and effective lesions.

[0090]

[0126] In some embodiments, catheter 102 includes one or more additional electrodes 125 (e.g., ring electrodes) positioned along shaft 120 proximal to delivery electrode 122, as illustrated in FIG. 2B. In some embodiments, some or all of the additional electrodes may be used for stimulation and recording (for electrophysiological mapping), and thus a separate cardiac mapping catheter is not required when using catheter 102 for lesion creation or other purposes, such as sensing.

[0091]

[0127] In some embodiments, the catheter 102 includes a thermocouple temperature sensor, optionally embedded in the delivery electrode 122. Similarly, in some embodiments, the catheter 102 includes a lumen that can be used for irrigation and / or aspiration. Typically, the lumen connects to one or more ports along the distal end of the catheter 102 for injection of isotonic saline solution for irrigation or for, for example, removal of microbubbles.

[0092]

[0128] In some embodiments, the catheter 102 includes one or more sensors that can be used to determine temperature, impedance, resistance, capacitance, conductivity, permittivity, and / or conductance, etc. In some embodiments, one or more of the electrodes act as the one or more sensors. In other embodiments, the one or more sensors are separate from the electrodes. Sensor data can be used to plan therapy, monitor therapy, and / or provide direct feedback via the processor 154, which can then modify the energy delivery algorithm 152. For example, impedance measurements can be used to determine the initial dose to be applied, as well as to determine whether further treatment is needed.

[0093]

[0129] 1 , in this embodiment, generator 108 includes a user interface 150, one or more energy delivery algorithms 152, a processor 154, a data storage / retrieval unit 156 (such as a memory and / or database), and an energy storage subsystem 158 that generates and stores the energy to be delivered. In some embodiments, one or more capacitors are used for energy storage / delivery, although any other suitable energy storage elements may be used. Also, one or more communication ports are included.

[0094]

[0130] In some embodiments, the generator 108 includes three subsystems: 1) a high-energy storage system, 2) a high-voltage, medium-frequency switching amplifier, and 3) a system controller, firmware, and user interface. In this embodiment, the system controller includes a cardiac synchronization trigger monitor that allows the pulse energy output to be synchronized to the patient's cardiac rhythm. The generator draws on alternating current (AC) mains to power multiple direct current (DC) power supplies. The generator controller can cause the DC power supplies to charge a high-energy capacitor storage bank before energy delivery begins. Upon initiation of therapeutic energy delivery, the generator controller, high-energy storage bank, and biphasic pulse amplifier can operate simultaneously to create a high-voltage, medium-frequency output.

[0095]

[0131] It will be appreciated that numerous generator electrical architectures can be employed to implement energy delivery algorithms. In particular, some embodiments use advanced switching systems capable of directing pulsed electric field circuits to energy delivery electrodes separately from the same energy storage and high-voltage delivery systems. Additionally, generators employed with advanced energy delivery algorithms employing rapidly changing pulse parameters (e.g., voltage, frequency, etc.) or multiple energy delivery electrodes may utilize modular energy storage systems and / or high-voltage systems to facilitate highly customizable waveform and geographic pulse delivery paradigms. It should further be appreciated that the electrical architectures described herein above are merely examples, and that systems delivering pulsed electric fields may or may not include additional switching amplifier components.

[0096]

[0132] The user interface 150 may include a touch screen and / or more traditional buttons that allow an operator to enter patient data, select a treatment algorithm (e.g., energy delivery algorithm 152), initiate energy delivery, view records stored on the storage / retrieval unit 156, and / or otherwise communicate with the generator 108.

[0097]

[0133] In some embodiments, the user interface 150 is configured to receive operator-defined input. The operator-defined input may include the duration of energy delivery, one or more other temporal aspects of the energy delivery pulse, power, and / or operational mode, or a combination thereof. Exemplary operational modes may include (but are not limited to) system initiation and self-test, operator input, algorithm selection, pre-treatment system status and feedback, energy delivery, post-energy delivery display or feedback, treatment data review and / or download, software update, or any combination or subcombination thereof.

[0098]

[0134] As mentioned above, in some embodiments, the system 100 also includes a mechanism for acquiring an electrocardiogram (ECG), such as an external cardiac monitor 110, in situations where cardiac synchronization is desired. Exemplary cardiac monitors are available from AccuSync Medical Research Corporation and Ivy Biomedical Systems, Inc. In some embodiments, the external cardiac monitor 110 is operably connected to the generator 108. The cardiac monitor 110 can be used to continuously acquire ECG signals. To acquire the ECG, external electrodes 172 can be applied to the patient P. The generator 108 analyzes one or more cardiac cycles and identifies the beginning of a period when it is safe to apply energy to the patient P, thus providing the ability to synchronize energy delivery with the cardiac cycle. In some embodiments, this period is within a few milliseconds of the R wave (of the ECG QRS complex) to avoid induction of arrhythmias, which can occur if the energy pulse is delivered at the T wave. It will be appreciated that such cardiac synchronization is typically utilized when using unipolar energy delivery, but may be utilized as part of other energy delivery methods.

[0099]

[0135] In some embodiments, processor 154, among other activities, modifies and / or switches energy delivery algorithms, monitors energy delivery and any sensor data, and reacts to the monitored data via a feedback loop. In some embodiments, processor 154 is configured to execute one or more algorithms for operating a feedback control loop based on one or more measured system parameters (e.g., current), one or more measured tissue parameters (e.g., impedance), and / or a combination thereof.

[0100]

[0136] The data storage / retrieval unit 156 stores data, e.g., related to delivered treatments, and optionally can be downloaded by connecting a device (e.g., a laptop or thumb drive) to the communications port. In some embodiments, the device has local software used to direct the download of information, e.g., instructions stored on the data storage / retrieval unit 156 and executable by the processor 154. In some embodiments, the user interface 150 allows an operator to select to download data to devices and / or systems such as, but not limited to, computer devices, tablets, mobile devices, servers, workstations, cloud computing devices / systems, and / or the like. The communications port, which can allow for wired and / or wireless connectivity, can enable data downloads as just described, but can also enable data uploads, such as uploading custom algorithms or providing software updates.

[0101]

[0137] As described herein, various energy delivery algorithms 152 may be programmable or pre-programmed into the generator 108, such as stored in a memory or data storage / retrieval unit 156. Alternatively, the energy delivery algorithms may be added to the data storage / retrieval unit to be executed by the processor 154. Each of these algorithms 152 may be executed by the processor 154.

[0102]

[0138] It will be appreciated that in some embodiments, the system 100 includes automatic therapy delivery algorithms that dynamically respond and adjust and / or terminate therapy in response to inputs such as temperature, impedance at various voltages or AC frequencies, treatment duration or other temporal aspects of the energy delivery pulse, treatment power, and / or system state.

[0103]

[0139] As described above, in some embodiments, the cardiac monitor provides a trigger signal to the generator 108 upon detecting the patient's cardiac cycle R wave. This trigger signal, and the generator's algorithm, ensures that energy delivery is synchronized with the patient's cardiac cycle to reduce the likelihood of arrhythmia due to the energy delivery. This trigger is within a few milliseconds of the peak of the R wave (of the ECG QRS complex) to avoid induction of arrhythmias that may occur if the energy pulse is delivered at the T wave and to ensure that the energy delivery occurs at a consistent phase of cardiac contraction. It will be appreciated that such cardiac synchronization is typically utilized when using unipolar energy delivery, but may also be utilized as part of other energy delivery methods.

[0104]

[0140] In this embodiment, the generator 108 is connected to an external cardiac monitor 110 to enable delivery of energy in coordination with cardiac signals sensed from the patient P.

[0105]

[0141] In some embodiments, the generator 180 receives feedback from the cardiac monitor 110 and responds based on the received information. In some embodiments, the generator 180 receives information regarding the patient's heart rate and modifies energy delivery, such as by stopping energy delivery or selecting a different energy delivery algorithm 152. In some embodiments, the generator 180 stops energy delivery when the heart rate reaches or falls below a threshold, such as 30 beats per minute (bpm) or 20 bpm. Optionally, the generator may provide an indicator, such as a visual or audible indicator, when the heart rate reaches or falls below a lower threshold, for example, providing a flashing yellow light when the heart rate reaches 30 bpm and a solid red light when the heart rate reaches 20 bpm. Such a safety measure ensures that therapeutic energy is not delivered at an inappropriate time, given that low sporadic heart rates may indicate erroneous readings.

[0106]

[0142] In some embodiments, the generator 108 modifies energy delivery based on information from the cardiac monitor 110. For example, in some embodiments, energy delivery is provided at a 1:1 ratio when the heart rate is within a predetermined range, such as between 40 bpm and 120 bpm. This involves delivery of PEF energy at an appropriate interval for each heart beat. In some embodiments, the generator 108 modifies energy delivery when the heart rate exceeds this range, such as when the heart rate exceeds 120 bpm. In some embodiments, energy delivery is modified to a 2:1 ratio (2 heart beats:1 delivery), with PEF energy delivered at an appropriate interval for every other heart beat. It will be appreciated that various ratios of the form m:n (m and n are integers), such as 3:1, 3:2, 4:1, 4:3, 5:1, etc., may be utilized. It will also be appreciated that in some embodiments, the heart rate may be paced to achieve a desired heart rate. Such pacing may be provided by a separate or integrated pacemaker. In some embodiments, such pacing is provided by a catheter positioned in the coronary sinus that is used for recording during the procedure but is also available for pacing. Such pacing can be triggered by the generator 108 or the cardiac monitor 110.

[0107]

[0143] In some embodiments, the generator 108 stops or modifies energy delivery based on information from other sources, such as from various sensors, including temperature sensors, impedance sensors, contact or contact force sensors, etc. In some embodiments, the generator 108 modifies energy delivery based on sensed temperature (e.g., on the catheter 102, in nearby tissue, in nearby structures, etc.). In some embodiments, the energy delivery is modified at a 2:1 ratio, with PEF energy being delivered at appropriate intervals of every other heartbeat once the temperature reaches a predetermined threshold. Such modification reduces any small thermal effects, thereby lowering the sensed temperature. It will be appreciated that various ratios may be utilized, such as 3:1, 3:2, 4:3, 4:1, 5:1, etc.

[0108]

[0144] As previously mentioned, one or more energy delivery algorithms 152 may be programmable or preprogrammed into the generator 108 for delivery to the patient P. The one or more energy delivery algorithms 152 specify electrical signals that provide energy delivered to cardiac tissue that is non-thermal (e.g., below the threshold for thermal ablation, below the threshold for inducing coagulative thermal damage), reduces or avoids inflammation, and / or prevents denaturation of interstitial proteins within the luminal structures. It will be appreciated that the non-thermal energy is also not cryogenic (i.e., above the threshold for thermal damage caused by freezing). Thus, the temperature of the target tissue remains within a range between baseline body temperature (such as 35°C to 37°C, but can be as low as 30°C) and the threshold for thermal ablation. Thus, target ranges for tissue temperature include 30-65°C, 30-60°C, 30-55°C, 30-50°C, 30-45°C, and 30-35°C. In this way, the tissue temperature remains below the thermal ablation threshold (e.g., 65°C), so lesions in the cardiac tissue are not created by thermal damage. In addition, the tissue impedance typically remains below the threshold created by thermal ablation. Charring and thermal damage to the tissue alter the electrical conductivity of the cardiac tissue. This increase in impedance / decrease in electrical conductivity often indicates thermal damage and reduces the tissue's ability to receive further energy. In some cases, the impedance of the system circuit from the cathode to the anode remains within a range of 25-250 Ω or 50-200 Ω during delivery of PEF energy. Generally, the algorithm 152 is tuned to affect tissue to a predetermined depth and / or volume and / or to target specific types of cellular responses to the delivered energy. However, it will be understood that the pulsed electric field energy described herein may be utilized more liberally than other types of energy, such as those that cause thermal damage, without adverse effects. For example, because the energy does not cause thermal damage, the tissue may be overtreated to ensure sufficient lesion formation. For example, in a 2 mm thick tissue layer, sufficient energy can be applied to the tissue to create a lesion having a depth of 6 mm to ensure a transmural lesion.Typically, additional energy is dissipated through transverse tissue planes from nearby critical structures. In particular, the pericardial fluid surrounding the heart helps dissipate energy and protects extracardiac structures, such as the esophagus, phrenic nerve, coronary arteries, lungs, and bronchioles, from damage. This is not the case when delivering energy that creates lesions through thermal injury. In such cases, propagation of conductive thermal energy beyond the targeted myocardial tissue can result in thermal injury to non-targeted extracardiac structures. Excessive thermal injury to the esophagus can result in esophageal ulcers, which can worsen into fatal atrioesophageal fistulas. Thermal injury to the phrenic nerve can result in permanent diaphragmatic paralysis, leading to permanent shortness of breath and fatigue. Thermal injury to the coronary arteries can result in coronary artery spasm, which can lead to temporary or even permanent chest tightness / chest pain. Additionally, cardiac thermal lesions around the pulmonary veins can lead to pulmonary vein stenosis. Pulmonary vein stenosis is a known complication of radiofrequency ablation near pulmonary veins in patients with atrial fibrillation. This pathological process is related to thermal damage to tissue, which induces postprocedural fibrosis and scarring. Stenosis has been described in patients treated with many forms of thermal energy, including radiofrequency energy and cryoablation.

[0109]

[0145] Because the PEF lesions described herein are not created by thermal injury, the rate of "false-positive" confirmation of electrical conduction block is also reduced. Thermal injury can result in acute myocardial edema (i.e., tissue fluid accumulation and swelling). When testing electrical conductivity across a thermally ablated tissue region, the tissue may appear to block electrical conduction, but such blockage may simply be the result of temporary edema. After a recovery period to allow swelling to subside, this region of treated tissue no longer has transmural electrical conductivity. In addition, acute edema resulting from thermal injury also reduces the ability to re-treat the tissue region. When a tissue region experiences a certain amount of thermal damage, the resulting edema alters the tissue's resistive and conductive thermal properties. Therefore, it is difficult to achieve an effect similar to the initial response in the tissue. Consequently, any re-treatment attempts, both acutely and chronically, will be less effective. These problems are avoided by the energy delivery described herein.

[0110]

[0146] Figure 3 illustrates a portion of the heart (H) and shows cross-sectional views of the right atrium (RA) and left atrium (LA) in the treatment of atrial fibrillation. The four largest pulmonary veins are the four major pulmonary veins (the right superior pulmonary vein (RSPV), the right inferior pulmonary vein (RIPV), the left superior pulmonary vein (LSPV), and the left inferior pulmonary vein (LIPV), two of which drain from each lung to the left atrium (LA) of the heart (H). Each pulmonary vein is connected to the capillary network of the alveoli of each lung and carries oxygenated blood to the left atrium (LA). The left atrial musculature extends from the left atrium (LA) and encases the proximal pulmonary veins. Superior veins, which have longer muscular sleeves, have been reported to be more arrhythmogenic than inferior veins. Generally, the length of the pulmonary vein sheath varies between 13 mm and 25 mm. Pulmonary vein morphology has been reported to influence arrhythmogenesis. Similarly, cellular electrophysiology and other aspects of the pulmonary veins are related to arrhythmogenesis and propagation.

[0111]

[0147] Various methods, such as anatomical adaptation and cardiac mapping, are used to determine which tissues are targeted for treatment. Typically, a mapping catheter is selected to preferably fit the pulmonary vein and conform to its size and anatomy. The mapping catheter allows for the recording of electrograms from the ostium of the pulmonary vein and from deep within the pulmonary vein, and these electrograms are displayed and timed for the user. The treatment catheter 102 is first placed deep within the pulmonary vein and gradually withdrawn proximally to the ostium. Mapping and treatment then begin.

[0112]

[0148] The current understanding of pulmonary vein electrophysiology is that most fibers within the pulmonary veins are circular and do not conduct electrical current within the veins. The electrical conduction pathway is the longitudinal fibers extending between the left atrium (LA) and the pulmonary veins. Pulmonary vein isolation is achieved by ablation of these connecting longitudinal fibers. For the left pulmonary veins, pacing the distal coronary sinus tends to increase the separation between the atrial signal and the pulmonary vein potential, making them more electrically visible. Signals from within the pulmonary veins are evaluated. Each individual signal consists of a generally small-amplitude far-field atrial signal and a sharp, localized pulmonary vein spike. The earliest pulmonary vein spike represents the site of connection between the pulmonary vein and the atrium. When the pulmonary vein spike and atrial potential are examined, these electrograms are widely separated at some of the mapping catheter poles, while at other sites there is a fused potential of the atrial and PV signals. The latter indicates the location of the longitudinal fibers and a potential site for treatment.

[0113]

[0149] In some embodiments, tissue surrounding the ostium of the left inferior pulmonary vein (LIPV) is treated in a point-by-point manner (with the aid of mapping) using the treatment catheter 102 to create a circular treatment zone around the left inferior pulmonary vein (LIPV), as illustrated in FIG. 3 . In some cases, dedicated navigation software may be used to enable proper positioning of the treatment catheter 120. A delivery electrode 122 is positioned near or relative to the target tissue region, and energy is provided to the delivery electrode 122 to create a treatment region A. Because energy is delivered to a localized region (local delivery), the electrical energy is concentrated over a smaller surface area, resulting in a stronger effect than delivery through electrodes extending circumferentially around the lumen or ostium. It also forces the electrical energy to be delivered in a stepwise, localized approach, mitigating the potential effects of preferential current paths through surrounding tissue. These preferential current paths are regions with electrical properties that induce a local increase in current flow therethrough rather than through adjacent regions. Such a path may result in an irregular current distribution around the target lumen, thus distorting the electric field and causing irregular increases in the therapeutic effect in some regions and lower therapeutic effect in others. This can be mitigated or avoided by using localized therapy to stabilize the therapeutic effect around the target region. Thus, by providing energy to a specific region at a time, the electrical energy is "forced" across different regions around the region, ensuring an improved degree of circumferential regularity of the treatment. FIG. 4 illustrates the repeated application of energy in a point-by-point manner around the left inferior pulmonary vein (LIPV) using a treatment catheter 102 to create a circular treatment zone. As shown, in this embodiment, each treatment region A overlaps with adjacent treatment regions A to create a continuous treatment zone. The size and depth of each treatment region A may depend on various factors, such as parameter values, number of treatments, and tissue characteristics. It will be understood that the number of treatment regions A may vary depending on various factors, particularly the unique conditions of each patient's anatomy and electrophysiology.In some embodiments, the number of treatment areas includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, or more.

[0114]

[0150] When all electrical connections between the atria and veins are treated, there is an electrical pause in the pulmonary veins and only far-field atrial signals are recorded. Occasionally, spikes of electrical activity are seen in the pulmonary veins without conduction to the rest of the atria, clearly demonstrating the electrical discontinuity of the veins from the rest of the atrial myocardium.

[0115]

[0151] Depending on the clinical indication, additional treatment regions may be created elsewhere to treat arrhythmias in either the right or left atrium. Tests are then performed to ensure that each target pulmonary vein is effectively isolated from the main body of the left atrium.

[0116] Energy Delivery Algorithm

[0152] It will be appreciated that a variety of energy delivery algorithms 152 may be used. In some embodiments, the algorithm 152 defines a signal having a waveform comprising a series of energy packets, each comprising a series of high-voltage pulses. In such embodiments, the algorithm 152 specifies parameters of the signal, such as the energy amplitude (e.g., voltage) and duration of the applied energy, including the number of packets, the number of pulses within a packet, and the fundamental frequency of the pulse sequence. Additional parameters may include the time to switch between polarities in a biphasic pulse, the dead time between biphasic cycles, and the rest time between packets, which are described in more detail in later sections. There may be a fixed rest period between packets, or the packets may be synchronized to the cardiac cycle and therefore variable depending on the patient's heart rate. There may be a deliberately varying rest period algorithm, or no rest period may be applied between packets. Feedback loops and automatic shutoff features based on sensor information, and / or the like may be included.

[0117]

[0153] FIG. 5 illustrates one embodiment of a waveform 400 of a signal defined by the energy delivery algorithm 152. Two packets are shown: a first packet 402 and a second packet 404; the packets 402, 404 are separated by a pause 406. In this embodiment, each packet 402, 404 consists of a first biphasic period (comprising a first positive pulse peak 408 and a first negative pulse peak 410) and a second biphasic period (comprising a second positive pulse peak 408′ and a second negative pulse peak 410′). The first and second biphasic pulses are separated by a dead time 412 (i.e., pause) between each biphasic period. In this embodiment, the biphasic pulses are symmetric; therefore, the set voltage 416 is the same for the positive and negative peaks. Note that the biphasic symmetric wave is also a square wave; therefore, the magnitude and duration of the positive voltage wave are approximately equal to the magnitude and duration of the negative voltage wave.

[0118] A. Voltage

[0154] The voltages used and considered may be the peaks of a square waveform, the peaks of a sinusoidal or sawtooth waveform, or the RMS voltage of a sinusoidal or sawtooth waveform. In some embodiments, energy is delivered in a unipolar manner and each high voltage pulse or set voltage 416 is between about 500V and 10,000V, particularly between about 1000V and 2000V, 2000V and 3000V, 3000V and 3500V, 3500V and 4000V, 3500V and 5000V, 3500V and 6000V, including all values ​​and subranges therebetween, such as between about 1000V, 2000V, 2500V, 2800V, 3000V, 3300V, 3500V, 3700V, 4000V, 4500V, 5000V, 5500V, 6000V, etc.

[0119]

[0155] It will be appreciated that the set voltage 416 may vary depending on whether the energy is delivered in a monopolar or bipolar manner. Lower voltages may be used in bipolar delivery due to the smaller, more directed electric field. While the bipolar voltage selected for use in therapy depends on the electrode separation, monopolar electrode configurations using one or more remote dispersive pad electrodes may be delivered without much consideration for the precise placement of the catheter electrode and dispersive electrode on the body. In monopolar electrode embodiments, higher voltages are typically used due to the dispersive behavior of the energy delivered through the body to reach the dispersive electrode at effective separation distances on the order of 10 cm to 100 cm. Conversely, in bipolar electrode configurations, the relatively close active areas of the electrodes, on the order of 0.5 mm to 10 cm, including 1 mm to 1 cm, increase the impact of separation distance on the concentration of electrical energy and the effective dose delivered to tissue. For example, if the target voltage-to-distance ratio to induce the desired clinical effect at the appropriate tissue depth (1.3 mm) is 3000 V / cm, if the separation distance is changed from 1 mm to 1.2 mm, this would require an increase in the treatment voltage from 300 to approximately 360 V, a change of 20%.

[0120] B.Frequency

[0156] It will be understood that the number of biphasic cycles per second is the frequency at which the signal is continuous. In some embodiments, biphasic pulses are utilized to reduce undesired muscle stimulation, particularly myocardial stimulation. In other embodiments, the pulse waveform is monophasic and does not have a distinct inherent frequency. Instead, the fundamental frequency can be considered by doubling the monophasic pulse length to derive the frequency. In some embodiments, the signal has a frequency in the range of 50 kHz to 1 MHz, more specifically, 50 kHz to 1000 kHz. It will be understood that at some voltages, frequencies below 100-250 kHz may cause undesired muscle stimulation. Thus, in some embodiments, the signal has a frequency in the range of 300-800 kHz, 400-800 kHz, or 500-800 kHz, such as 300 kHz, 400 kHz, 450 kHz, 500 kHz, 550 kHz, 600 kHz, 650 kHz, 700 kHz, 750 kHz, or 800 kHz. Additionally, cardiac synchronization is typically utilized to reduce or avoid unwanted myocardial stimulation during sensitive rhythm periods, and it will be appreciated that even higher frequencies may be used with components that minimize signal artifacts.

[0121] C. Voltage and Frequency Balance

[0157] The frequency of the delivered waveform may be varied synchronously with the treatment voltage to maintain sufficient therapeutic effect. Such synergistic changes would involve a decrease in frequency that produces a stronger effect combined with a decrease in voltage that produces a weaker effect. For example, in some cases, treatment may be delivered in a monopolar manner using 3000V with a waveform frequency of 600kHz, while in other cases, treatment may be delivered using 2000V with a waveform frequency of 400kHz.

[0122] D. Packet

[0158] As described above, the algorithm 152 typically defines a signal having a waveform comprising a series of energy packets, each comprising a series of high-voltage pulses. The cycle count 420 is half the number of pulses in each biphasic packet. Referring to FIG. 5, the first packet 402 has a cycle count 420 of 2 (i.e., four biphasic pulses). In some embodiments, the cycle count 420 is set between 2 and 1000 per packet, including all values ​​and subranges therebetween. In some embodiments, the period count 420 is between 5 and 1000 per packet, between 2 and 10 per packet, between 2 and 20 per packet, between 2 and 25 per packet, between 10 and 20 per packet, between 20 and 30 per packet, 25 per packet, between 20 and 40 per packet, 30 per packet, between 20 and 50 per packet, between 30 and 60 per packet, up to 60 per packet, up to 80 per packet, up to 100 per packet, up to 1,000 per packet, or up to 2,000 per packet, including all values ​​and subranges therebetween.

[0123]

[0159] Packet duration is determined by, among other factors, the cycle count. For a given pulse width (or sequence of positive and negative pulse widths in a biphasic waveform), the higher the cycle count, the longer the packet duration and the greater the amount of energy delivered. In some embodiments, the packet duration is in the range of approximately 50-1000 microseconds, such as 50 μs, 60 μs, 70 μs, 80 μs, 90 μs, 100 μs, 125 μs, 150 μs, 175 μs, 200 μs, 250 μs, 100-250 μs, 150-250 μs, 200-250 μs, or 500-1000 μs. In other embodiments, the packet duration is in the range of approximately 100-1000 microseconds, such as 150 μs, 200 μs, 250 μs, 500 μs, or 1000 μs.

[0124]

[0160] The number of packets, or packet count, delivered during a treatment typically ranges from 1 to 250 packets, including all values ​​and subranges therebetween, hi some embodiments, the number of packets delivered during a treatment comprises 10 packets, 15 packets, 20 packets, 25 packets, 30 packets, or more than 30 packets.

[0125] E. Break Period

[0161] In some embodiments, the time between packets, referred to as the idle period 406, is set to between about 0.001 seconds and about 5 seconds, including all values ​​and subranges therebetween. In other embodiments, the idle period 406 ranges from about 0.01 to 0.1 seconds, including all values ​​and subranges therebetween. In some embodiments, the idle period 406 is between about 0.5 ms and 500 ms, between 1 and 250 ms, or between 10 and 100 ms, etc.

[0126] F. Batch

[0162] In some embodiments, the signal is synchronized with the cardiac rhythm so that each packet is delivered synchronously within a designated period relative to the heartbeat, and thus the resting periods coincide with the heartbeat. It will be appreciated that the packets delivered within each designated period relative to the heartbeat may be considered a batch or bundle. Thus, each batch has a desired number of packets, such that a desired total number of packets has been delivered at the end of the therapy period. While each batch may have the same number of packets, in some embodiments, the batches have varying numbers of packets.

[0127]

[0163] In some embodiments, only one packet is delivered between heartbeats. In such cases, the pause period can be considered the same as the period between batches. However, when more than one packet is delivered between batches, the pause time is typically different from the period between batches. In such cases, the pause time is typically much shorter than the period between batches. In some embodiments, each batch includes 1 to 10 packets, 1 to 5 packets, 1 to 4 packets, 1 to 3 packets, 2 to 3 packets, 2 packets, 3 packets, 4 packets, 5 packets, 5 to 10 packets, etc. In some embodiments, each batch has a duration of 0.5 ms to 1 sec, 1 ms to 1 sec, 10 ms to 1 sec, 10 ms to 100 ms, etc. In some embodiments, the period between batches is variable depending on the patient's heart rate. In some cases, the period between batches is 0.25 to 5 seconds.

[0128]

[0164] Treatment of the tissue region continues until the desired number of batches have been delivered to the tissue region. In some embodiments, 2-50 batches are delivered per treatment, and a treatment is considered a treatment of a particular tissue region. In other embodiments, the treatment includes 5-40 batches, 5-30 batches, 5-20 batches, 5-10 batches, 5 batches, 6 batches, 7 batches, 8 batches, 9 batches, 10 batches, 10-15 batches, etc.

[0129] G. Switching Times and Dead Times

[0165] The switching time is the delay or period of no delivered energy between the positive and negative peaks of a biphasic pulse, as illustrated in FIG. 5. In some embodiments, the switching time ranges from about 0 to about 1 microsecond, including all values ​​and subranges therebetween. In other embodiments, the switching time ranges from 1 to 20 microseconds, including all values ​​and subranges therebetween. In other embodiments, the switching time ranges from about 2 to about 8 microseconds, including all values ​​and subranges therebetween.

[0130]

[0166] A delay may also be inserted between each biphasic cycle, referred to as "dead time." Dead time occurs within a packet, but between biphasic pulses. This is in contrast to the rest periods that occur between packets. In other embodiments, dead time 412 is within the range of approximately 0 to 0.5 microseconds, 0 to 10 microseconds, 2 to 5 microseconds, 0 to 20 microseconds, about 0 to about 100 microseconds, or about 0 to about 100 milliseconds, including all values ​​and subranges therebetween. In some embodiments, dead time 412 is within the range of 0.2 to 0.3 microseconds. Dead time may also be used to define the period between separate monophasic pulses within a packet.

[0131]

[0167] Delays such as switching times and dead times are introduced into the packets to reduce the effects of biphasic cancellation within the waveform. In some cases, both the switching time and dead time are increased together to enhance the effect. In other cases, only the switching time or only the dead time is increased to induce this effect.

[0132] H. Waveform

[0168] 5 illustrates an embodiment of a waveform 400 having symmetric pulses, such that the voltage and duration of the pulse in one direction (i.e., positive or negative) are equal to the voltage and duration of the pulse in the other direction. FIG. 6 illustrates an exemplary waveform 400 defined by another energy delivery algorithm 152, where the waveform 400 has a voltage imbalance. Here, two packets, a first packet 402 and a second packet 404, are shown, separated by a rest period 406. In this embodiment, each packet 402, 404 consists of a first biphasic period (comprising a first positive pulse peak 408 having a first voltage V1 and a first negative pulse peak 410 having a second voltage V2) and a second biphasic period (comprising a second positive pulse peak 408' having a first voltage V1 and a second negative pulse peak 410' having a second voltage V2). Here, the first voltage V1 is greater than the second voltage V2. The first and second biphasic cycles are separated by a dead time 412 between each pulse. Thus, the voltage in one direction (i.e., positive or negative) is greater than the voltage in the other direction, and as a result, the area under the positive portion of the curve is not equal to the area under the negative portion of the curve. This unequal waveform may result in a more pronounced therapeutic effect because the predominant positive or negative amplitude leads to a longer duration of the same charge cell membrane charge potential. In this embodiment, the first positive peak 408 has a set voltage 416 (V1) that is greater than the set voltage 416' (V2) of the first negative peak 410. Figure 7 illustrates a further example of a waveform with unequal voltages. For simplification, four different types of packets are shown in a single diagram. The first packet 402 consists of pulses with unequal voltages but equal pulse widths, with no switching time or dead time. Thus, the first packet 402 consists of four biphasic pulses, each having a positive peak 408 with a first voltage V1 and a negative peak 410 with a second voltage V2, where the first voltage V1 is greater than the second voltage V2.The second packet 404 consists of pulses with unequal voltages but symmetric pulse widths (as in the first pulse 402) and has a switching time equal to the dead time. The third packet 405 consists of pulses with unequal voltages but symmetric pulse widths (as in the first pulse 402) and has a switching time shorter than the dead time. The fourth packet 407 consists of pulses with unequal voltages but symmetric pulse widths (as in the first pulse 402) and has a switching time longer than the dead time. In some embodiments, the positive and negative phases of a biphasic waveform are balanced, although not identical, if the voltage in one direction (i.e., positive or negative) is greater than the voltage in the other direction, but the pulse lengths are calculated so that the area under the curve for the positive phase is equal to the area under the curve for the negative phase.

[0133]

[0169] In some embodiments, the imbalance includes pulses having pulse widths of unequal duration. In some embodiments, a biphasic waveform is unbalanced, such that the voltage in one direction is equal to the voltage in the other direction, but the duration of one direction (i.e., positive or negative) is longer than the duration of the other direction, such that the area under the curve of the positive portion of the waveform is not equal to the area under the negative portion of the waveform.

[0134]

[0170] FIG. 8 illustrates further examples of waveforms with unequal pulse widths. For brevity, four different types of packets are shown in a single figure. The first packet 402 consists of pulses with equal voltages but unequal pulse widths, with no switching time or dead time. Thus, the first packet 402 consists of four biphasic pulses, each with a positive peak 408 having a first pulse width PW1 and a negative peak 410 having a second pulse width PW2. Here, the first pulse width PW1 is greater than the second pulse width PW2. The second packet 404 consists of pulses with equal voltages but unequal pulse widths (as in the first pulses 402) with a switching time equal to the dead time. The third packet 405 consists of pulses with equal voltages but unequal pulse widths (as in the first pulses 402) with a switching time shorter than the dead time. The fourth packet 407 consists of pulses with equal voltages (as in the first pulses 402) but unequal pulse widths, with switching times longer than the dead time.

[0135]

[0171] FIG. 9 illustrates an exemplary waveform 400 defined by another energy delivery algorithm 152. The waveform is monophasic, a special case of imbalance where only the positive or negative portions of the waveform are present. Here, two packets, a first packet 402 and a second packet 404, are shown, separated by a rest period 406. In this embodiment, each packet 402, 404 consists of a first monophasic pulse 430 and a second monophasic pulse 432. The first and second monophasic pulses 430, 432 are separated by a dead time 412 between each pulse. This monophasic waveform may lead to a more desirable therapeutic effect because the same charge cell membrane potential is maintained for a longer duration. However, compared to a biphasic waveform, adjacent muscle groups may be stimulated more with a monophasic waveform.

[0136]

[0172] FIG. 10 illustrates a further example of a waveform with monophasic pulses. For brevity, four different types of packets are shown in a single figure. The first packet 402 consists of pulses with the same voltage and pulse width, no switching time (because the pulses are monophasic), and a dead time equal to the active time. In some cases, there may be a period of dead time shorter than the active time of a given pulse. Thus, the first packet 402 consists of three monophasic pulses 430, each with a positive peak. If the dead time is equal to the active time, the waveform can be considered unbalanced with a fundamental frequency representing a repetition cycle with two active times and no dead time. The second packet 404 consists of monophasic pulses 430 with equal voltages and pulse widths (as in the first packet 402) and a longer dead time. The third packet 405 consists of monophasic pulses 430 with equal voltages and pulse widths (as in the first packet 402) and an even longer dead time. The fourth packet 407 consists of monophasic pulses 430 with uniform voltage and pulse width (as in the first packet 402), with a longer dead time.

[0137]

[0173] In some embodiments, an unbalanced waveform is achieved by delivering more than one pulse of one polarity before reversing to an unequal number of pulses of the opposite polarity. FIG. 11 illustrates a further example of a waveform with such phase imbalance. Here, for condensed explanation, four different types of packets are shown in a single diagram. The first packet 402 consists of four cycles with equal voltages and pulse widths, but pulses of opposite polarity are intermixed with monophasic pulses. Thus, the first cycle includes a positive peak 408 and a negative peak 410. The second cycle is monophasic, with a single positive pulse and no subsequent negative pulse 430. This then repeats. The second packet 404 consists of intermixed biphasic and monophasic cycles (as in the first packet 402), but the pulses have unequal voltages. The third packet 405 consists of mixed biphasic and monophasic cycles (as in the first packet 402), but the pulses have unequal pulse widths. The fourth packet 407 consists of mixed biphasic and monophasic cycles (as in the first packet 402), but the pulses have unequal voltages and unequal pulse widths. Thus, multiple combinations and permutations are possible.

[0138] I. Waveform shape

[0174] FIG. 12 illustrates an exemplary waveform 400 defined by another energy delivery algorithm 152, in which the pulses are sinusoidal rather than square in shape. Again, two packets are shown, a first packet 402 and a second packet 404, with the packets 402, 404 separated by a rest period 406. In this embodiment, each packet 402, 404 consists of three biphasic pulses 440, 442, 444. And, rather than square waves, these pulses 440, 442, 444 are sinusoidal in shape. One advantage of the sinusoidal shape is that it is balanced or symmetrical, whereby each phase is equal in shape. Balancing can help reduce undesired muscle stimulation. It will be understood that in other embodiments, the pulses have decaying waveforms.

[0139]

[0175] Energy delivery can be activated by a variety of mechanisms, such as with the use of a button 164 on the catheter 102 or a footswitch 168 operably connected to the generator 104. Such activation typically provides a single energy dose. The energy dose is defined by the number of packets delivered and the voltage of the packets. Each energy dose delivered to the tissue maintains the temperature at or within the tissue below the threshold for thermal ablation. Additionally, the dose may be titrated or adjusted over time to further reduce or eliminate heat buildup during the treatment procedure. Instead of inducing thermal damage, defined as protein coagulation at sites dangerous to the therapy, the energy dose provides energy at a level that induces and treats the condition without damaging sensitive tissue.

[0140] Therapeutic catheter design

[0176] The systems and devices described herein can be used with various types and styles of treatment catheters 102. In some embodiments, the treatment catheter 102 is designed to deliver a localized therapy, while in other embodiments, the treatment catheter 102 is designed to deliver a "one-shot" therapy. Localized therapy is considered to be a therapy in which energy is delivered sequentially, such as by repeatedly applying energy in a point-by-point manner around a pulmonary vein to create a circular treatment zone as previously shown in FIG. 4 , or along a line, curve, etc. One-shot therapy is considered to be a therapy in which energy is delivered in a "one-shot" around the entire circumference of the entrance to the pulmonary vein via an energy delivery body or one or more delivery electrodes, although such delivery may be repeated if desired. This may optionally include rotation of the energy delivery body or electrode 122 between "shots," if desired.

[0141] Local therapy

[0177] As previously mentioned, local therapy is often performed using a delivery electrode 122 having a cylindrical shape with a distal surface, as illustrated in FIGS. 2A-2B. Here, the distal surface is flat and circular. In some embodiments, the distal surface of the delivery electrode 122 has a diameter of 2-3 mm. In such embodiments, when the treatment catheter 102 is positioned perpendicular to the tissue, the distal surface can cover a portion of the tissue having a diameter of 2-3 mm. However, larger portions of tissue may be covered by alternative device designs described herein. Such larger coverage may provide for larger lesion sizes in a single application.

[0142]

[0178] 13A-13C illustrate one embodiment of a treatment catheter 502 configured for localized delivery, optionally covering a larger area of ​​tissue than the cylindrically shaped delivery electrodes typically found in conventional RF catheters. Here, the catheter 502 comprises an elongate shaft 520 having an energy delivery body near its distal end 524, the energy delivery body comprising at least one delivery electrode 522. Notably, in this embodiment, the catheter 502 includes multiple electrodes arranged to form a continuous shape (i.e., a continuous outer edge) and, therefore, optionally, a continuous lesion. While a continuous lesion can be formed by energizing multiple electrodes simultaneously or non-simultaneously, it will be appreciated that in some embodiments, a subset of the multiple electrodes (including only one) can be energized to create a lesion that is smaller than a continuous shape, if desired. In such cases, it will also be appreciated that a continuous lesion can ultimately be created by manipulating the catheter 502, such as by rotating or repositioning, if it is not desired to create a continuous lesion at the initial location.

[0143]

[0179] 13A provides a side view of the catheter 502, showing the at least one delivery electrode 522 comprising four loop-shaped electrodes: a first electrode 530, a second electrode 532, a third electrode 534, and a fourth electrode 536. Each of the plurality of electrodes 530, 532, 534, and 536 is comprised of a wire 508 formed or shaped into a petal or loop shape, with a narrower shape near the shaft 520 and a larger, wider shape extending away from the shaft 520. Thus, the electrodes 530, 532, 534, and 536 fan out or extend outward from the shaft 520 in the shape of a blooming flower, as shown in the perspective view of FIG. 13B. In this embodiment, the sides 540 of each loop shape are disposed adjacent to one another and are joined to one another. Thus, the first electrode 530 is joined on one side to the adjacent second electrode 532 and on the opposite side to the adjacent fourth electrode 536. This provides stability to the overall design and maintains the relative positions of the electrodes 530, 532, 534, 536 throughout delivery and use. In some embodiments, the sides 540 are joined with a material that insulates the sides 540, thereby preventing conduction of energy therethrough. This focuses the energy delivery through each loop-shaped distal edge 542 configured to contact tissue.

[0144]

[0180] FIG. 13C provides a top-down view of electrodes 530, 532, 534, and 536 pressed against a surface. As shown, the distal edge 542 of each loop shape contacts the surface and together form a ring or circular shape, with the sides 540 appearing like the "spokes" on a "wheel." As the distal edges 542 press against tissue, energy is delivered therethrough. Typically, the resulting lesion is larger than the width of wire 508. Therefore, small gaps between loop shapes do not reduce the lesion because the resulting lesion overwhelms the effect of the small gap. In some embodiments, wire 508 has a diameter of 0.0075 inches, and the resulting lesion has a width of 12 mm (i.e., measured across the width of the wire). Thus, in some embodiments, the lesion has a ring, circular, or donut shape. It will be appreciated that in some embodiments, the lesion is large enough to connect through the center of the ring shapes, thus appearing to be a solid circle. In some embodiments, the catheter 502 includes an additional central electrode 548, as illustrated in Figures 13A-13C. The central electrode 548 extends distally from the central or longitudinal axis of the shaft 520. In some embodiments, the central electrode 548 does not extend longitudinally to the plane of the distal edge 542 when in the relaxed position, as illustrated in Figures 13A-13B. In such embodiments, the central electrode 548 contacts the tissue surface when the distal edge 542 is pressed against the tissue surface and the loop unfolds to flatten against the tissue, as in Figure 13C. Delivery of energy through the central electrode 548 in this position creates a central lesion, which helps create a continuous lesion within the footprint of the loop-shaped electrodes 530, 532, 534, and 536.

[0145]

[0181] 14A-14D illustrate the delivery of the embodiment of the catheter 502 of FIGS. 13A-13C. It will be appreciated that the wire 508 can be made of a variety of materials, such as nitinol or a drawn-out fill tube (e.g., 10% platinum / nitinol). In this embodiment, the wire 508 is flexible so that it can be folded within the delivery sheath 550, as shown in FIG. 14A. This allows the distal end of the catheter 502 to be successfully advanced to the target tissue site. Typically, the delivery sheath 550 has an inner diameter in the range of 2.5 mm to 3.5 mm. Progressive exposure of the electrodes 530, 532, 534, and 536 can be achieved by advancing the catheter 502 within the delivery sheath 550, or the delivery sheath 550 may be retracted to reveal the distal end of the catheter 502. Figure 14B illustrates the distal end of the catheter 502 emerging from the delivery sheath 550, with the loop-shaped electrodes 530, 532, 534, and 536 beginning to flare outward. Figure 14C illustrates the catheter 502 further emerging from the delivery sheath 550, with the loop-shaped electrodes 530, 532, 534, and 536 extending further radially outward from the longitudinal axis 552 of both the catheter 502 and the delivery sheath 550. Figure 14D illustrates the full exposure of the loop-shaped electrodes 530, 532, 534, and 536, allowing the loop-shaped electrodes 530, 532, 534, and 536 to spring back to their fully relaxed, expanded state. It will be appreciated that the loop-shaped electrodes 530, 532, 534, 536 can be further expanded to create a larger footprint by pressing the electrodes 530, 532, 534, 536 against a surface. In some embodiments, the maximum diameter is 9-15 mm, which can create lesions with similar or larger diameters due to field effects.

[0146]

[0182] In some embodiments, the overall lesion size created by the footprint of the treatment catheter 502 of FIGS. 13A-13C is larger than the lesion size created by the footprint of the solid-tip treatment catheter 102 of FIGS. 2A-2B. FIG. 15 provides a visual illustration of adjacent end effectors in contact with tissue. Here, the solid-tip treatment catheter 102 has a delivery electrode 122 with a circular surface measuring 3 mm in diameter. The treatment catheter 502 has a delivery electrode 522 comprising four loop-shaped electrodes, with electrodes 530, 532, 534, and 536 collectively forming a circular surface measuring 9-10 mm in diameter. This larger footprint is at least three times the size of the smaller footprint. In some cases, the larger footprint is up to six times the size of the smaller footprint. Thus, the difference in size between the delivery electrodes, and therefore the footprints, is typically in the range of three to six times. Because the delivery electrode 122 of the solid-tip treatment catheter 102 typically has the same diameter as its shaft, the dimensions of the delivery electrode 522 in the extended configuration have the same relationship to the shaft of the treatment catheter 502 as they do to the solid-tip treatment catheter 102 (i.e., the delivery electrode in the extended configuration is 3 to 6 times the diameter of the shaft of the treatment catheter 502). This larger diameter footprint can provide several advantages. In some cases, the larger footprint allows a user to perform a complete treatment protocol with fewer lesions. For example, when encircling a pulmonary vein using the solid-tip treatment catheter 102 as illustrated in FIG. 4, a user may create 35 lesions to complete a full-circle lesion. However, when performing this same procedure using the treatment catheter 502 of FIGS. 13A-13C, a user may create a full-circle lesion with 12 lesions. It will be understood that the treatment catheter 502 may be configured with a variety of different diameter footprints, with such diameters corresponding proportionally to the number of lesions desired to create a full circle. Such logic is amenable to other shapes of lesions, such as linear lesions, and other types of treatments. In many cases, the larger the lesion, the fewer lesions utilized to deliver the treatment. This typically reduces treatment time and translates into shorter procedures.Another advantage of the loop-shaped electrode design is the ability to create a larger footprint while maintaining healthy tissue within the center of the footprint. Thus, when a ring-shaped lesion is created surrounding healthy tissue, more of the healthy cardiac tissue is maintained than if the lesion were a solid disk-shaped lesion. Adjacent ring-shaped lesions can block electrical conduction through cardiac tissue as effectively as solid disk-shaped lesions while maintaining a higher percentage of healthy tissue. In some embodiments, the ring shape maintains 25% more healthy tissue.

[0147]

[0183] It will be appreciated that in some embodiments, the overall diameter or footprint size can be controlled by adjusting the deployment of the loop-shaped electrodes 530, 532, 534, 536 from the delivery sheath 550. For example, a smaller diameter can be achieved by only partially advancing the loop-shaped electrodes 530, 532, 534, 536 from the sheath 550, as in Figures 14B-14C. Similarly, a larger diameter can be achieved by fully advancing the loop-shaped electrodes 530, 532, 534, 536 from the sheath 550. Additionally, various catheters 502 can be designed with energy delivery electrodes 522 of different maximum diameters to suit various needs.

[0148]

[0184] It will also be appreciated that the overall diameter or footprint dimensions may be configured such that the delivery electrode 522 can provide one-shot therapy. Again, one-shot therapy is considered to be therapy in which energy is delivered in "one shot" via the delivery electrode 522 to an entire treatment area, such as around the entrance to a pulmonary vein, although such delivery may be repeated if desired. This may optionally include rotation of the electrode 122 between "shots," if desired. In such an embodiment, the overall diameter may be in the range of 22-33 mm.

[0149]

[0185] It will be appreciated that the energy delivery body or energy delivery electrodes 522 of the treatment catheter 502 can have any suitable number of loop-shaped electrodes, including two, three, four, five, six, seven, eight, nine, ten, or more. Similarly, the electrodes can be energizable together or independently. When electrodes are independently energized, they may be energized sequentially or in various patterns. Similarly, in some embodiments, a subset (including only one) of the multiple electrodes may be energized. This provides a wide variety of options for creating desired lesions.

[0150]

[0186] FIG. 16 illustrates another embodiment of a treatment catheter 602 configured for local delivery or one-shot therapy, optionally covering a larger area of ​​tissue than the cylindrically shaped delivery electrodes typically found in conventional RF catheters. This embodiment is similar to the embodiment of FIGS. 13A-13C in that the catheter 602 includes multiple loop-shaped electrodes arranged to form a continuous shape (i.e., a continuous outer edge) and, therefore, optionally, a continuous lesion. In this embodiment, the delivery electrodes 622 include six (rather than four) loop-shaped electrodes: a first electrode 630, a second electrode 632, a third electrode 634, a fourth electrode 636, a fifth electrode 638, and a sixth electrode 640. However, it will be understood that any number of electrodes may be utilized, such as up to 10-12 electrodes. Again, a continuous lesion can be formed by energizing multiple electrodes simultaneously or non-simultaneously, although it will be appreciated that in some embodiments, if desired, a subset (including only one) of the multiple electrodes can be energized to create a lesion that is smaller than a continuous shape. In such cases, it will also be appreciated that if it is not desired to create a continuous lesion at the initial location, a continuous lesion can ultimately be created by manipulating catheter 602, such as by rotating or repositioning.

[0151]

[0187] 16, each of the plurality of electrodes 630, 632, 634, 636, 638, and 640, when activated, fans out or extends outward from the shaft 620 in the shape of a blooming flower. In this embodiment, the loop-shaped sides 642 are disposed adjacent to and joined to one another. Thus, the first electrode 630 is joined to the adjacent second electrode 632 on one side and to the adjacent sixth electrode 640 on the opposite side.

[0152]

[0188] It will be appreciated that the overall diameter of the energy delivery body or delivery electrode 622 can be configured for local therapy, one-shot therapy, or both. FIG. 16 illustrates one embodiment sized for one-shot therapy, with an overall diameter or footprint dimension of 30 mm, as indicated by ruler measurement. It will be appreciated that for one-shot therapy, such diameters are typically in the range of 22-33 mm. Similarly, FIG. 17 illustrates the embodiment of FIG. 16 positioned relative to a laboratory benchtop model of an entrance to a pulmonary vein PV. As shown, the outer edges of electrodes 630, 632, 634, 636, 638, and 640 collectively extend around the perimeter of the model entrance to the pulmonary vein to provide one-shot therapy. It will be appreciated that the dimensions can be adjusted for local delivery by incremental deployment (similar to FIGS. 14A-14D) or by creating a delivery electrode 622 with a smaller overall diameter, such as in the range of 9-15 mm. Combinations for local therapy and one-shot therapy are described herein.

[0153]

[0189] 18A-18B illustrate the delivery electrode 622 deployed from the delivery sheath 650 so that the electrodes 630, 632, 634, 636, 638, and 640 extend generally perpendicular to the longitudinal axis of the delivery sheath 650. In this configuration, the outer edges of the electrodes 630, 632, 634, 636, 638, and 640 expand to reach their maximum diameter or footprint dimension. FIG. 18B shows the delivery electrode 622 positioned against a flat surface, such as representing a tissue plane, illustrating that the electrodes 630, 632, 634, 636, 638, and 640 can lie generally flat against the surface.

[0154]

[0190] Further extension of the electrodes 630, 632, 634, 636, 638, and 640 from the sheath 650 allows the petal-shaped electrodes 630, 632, 634, 636, 638, and 640 to curve downward, so that the outer edges of the electrodes 630, 632, 634, 636, 638, and 640 are disposed proximal to the distal tip of the sheath 650, as illustrated in FIG. 19 . This is achieved by preformed curvatures in the sides 640, which can spring back toward their preformed shape upon further release. The pre-curving causes the sides 640 to arc distally and then bend proximally, so that the overall shape of the delivery electrode 622 resembles an umbrella or mushroom cap. In this configuration, the delivery electrode 622 is preferentially positioned to deliver energy to an intraluminal surface, such as within the pulmonary vein PV. Here, positioning of the delivery electrode 622 relative to the entrance of the pulmonary vein PV allows the outer edges of the electrodes 630, 632, 634, 636, 638, and 640 to lie along the periphery of the pulmonary vein PV, while the side 642 extends along the inner lumen of the pulmonary vein PV and into the pulmonary vein PV. In some embodiments, the side 642 is insulated, such that such positioning provides stability while energy is delivered through the outer edges of the electrodes 630, 632, 634, 636, 638, and 640. In other embodiments, the side 642 is not insulated, such that such positioning allows energy delivery to portions of the inner lumen of the pulmonary vein PV via the side 642. This may aid in creating larger or more complex lesions.

[0155]

[0191] Further deployment of the electrodes 630, 632, 634, 636, 638, and 640 exaggerates this shape, allowing the side 640 to bend or arc even more, as illustrated in FIG. 20 . In this configuration, the delivery electrode 622 is preferentially positioned to deliver localized energy to the surface of the tissue by positioning the side 642 against the surface. In such a configuration, the delivery electrode 622 can be used such that the outer edges of the electrodes 630, 632, 634, 636, 638, and 640 do not contact the tissue, and energy is delivered to the tissue via the side 642. The rounded curvature of the side 642 allows the delivery electrode 622 to be "rolled" along the tissue, such that it has a ball shape, and the curved surface can engage the tissue by tilting the shaft 620 (within the sheath 650) of the catheter 602. This provides unlimited engagement positions and high flexibility in energy delivery. This embodiment is thus able to transition between configurations to provide either one-shot or localized therapy, and is therefore particularly suitable for combination use.

[0156]

[0192] It will be appreciated that the embodiments of Figures 16-20 can optionally be delivered through the outer edges of the electrodes 630, 632, 634, 636, 638, 640, through the pedal-shaped sides 642, or both simultaneously, alternatively, or in any combination. Thus, ring or donut-shaped lesions can be created, or solid circular-shaped lesions can be created, each of various dimensions.

[0157]

[0193] FIG. 21 illustrates an embodiment of a treatment catheter 702 configured for localized delivery rather than one-shot or combination delivery. Here, the lesions formed have a solid circular shape, making them suitable for treating tissue surfaces primarily in a point-by-point manner, etc., due to the shape and configuration of its delivery electrode 722. FIG. 22 illustrates an embodiment of a treatment catheter 702 in which the energy delivery body or delivery electrode 722 comprises multiple trowel-shaped electrodes 730, 732, 734, 736 extending from a shaft 720. Each trowel-shaped electrode has a generally triangular shape, with a tip 738 of the triangular shape near the center of the lesion to be formed, a side 740 of the triangular shape extending radially outward from the center of the lesion to be formed, and a base 742 of the triangular shape extending along the periphery of the lesion to be formed. In this embodiment, the tip 738 is a free end, and the base 742 is attached to the catheter 702 by a support 744. Thus, the tips 738 of the trowel-shaped electrodes 730, 732, 734, 736 can bend distally and proximally to accommodate anatomical variations in the tissue surface against which the delivery electrode 722 is placed. The tips 738 and sides 740 of the trowel-shaped electrodes 730, 732, 734, 736 also aid in creating continuous lesions rather than donut-shaped lesions.

[0158]

[0194] Figure 23 illustrates a side view of one embodiment of a treatment catheter 702 similar to that of Figures 21-22. Here, only two trowel-shaped electrodes 730, 732 are visible. As shown, the trowel-shaped electrodes 730, 732 are aligned along a plane perpendicular to the shaft 720. The plane is spaced distally from the distal end of the shaft 720 as determined by the length of the support 744. In some embodiments, irrigation is provided by an irrigation lumen 760 extending from the distal end of the shaft 720. This allows for the delivery of irrigation fluid in the area of ​​lesion formation.

[0159]

[0195] It will be appreciated that there may be any suitable number of trowel-shaped electrodes, typically three, four, five, six, seven, eight, or more, and that the trowel-shaped electrodes may be activated independently, together, or in any combination, such as in pairs, groups, or sequential patterns of individual or grouped electrodes.

[0160]

[0196] It will also be appreciated that any portion of the trowel-shaped electrode may be insulated to focus energy delivery through a particular region. In this embodiment, the support portion 744 is insulated to direct energy through the triangular shaped portion of the trowel-shaped electrode. It will also be appreciated that various sensors, such as microsensors for contact feedback or electroanatomical mapping systems, may be positioned along the trowel-shaped electrode. In this embodiment, such sensors are located along the base 744, but the sensors may be positioned along any suitable portion.

[0161]

[0197] FIG. 24 illustrates another embodiment of a treatment catheter 802. Here, a delivery electrode 822 includes multiple trowel-shaped electrodes 830, 832, 834, and 836 extending from a shaft 820. Again, each trowel-shaped electrode has a generally triangular shape, with a tip 838 of the triangular shape near the center of the lesion to be formed, a side 840 of the triangular shape extending radially outward from the center of the lesion to be formed, and a base 842 of the triangular shape extending along the periphery of the lesion to be formed. However, in this embodiment, the base 842 is a free end, and the tip 838 is attached to the catheter 802 by a support 844. In some embodiments, the support 844 is pre-curved to bias radially outward from the shaft 820. Typically, the support 844 is made of a material that provides flexibility and resilience, allowing the support 844 to bend toward the shaft 820 and then, upon release, to spring back to the pre-curved configuration. This provides the ability to move the trowel-shaped electrodes 830, 832, 834, and 836, for example, to create lesions of different sizes. In this embodiment, the support 844 extends along at least a portion of the shaft 820, such as within a longitudinal groove 852 along the shaft 820. Similarly, in this embodiment, the sheath 850 is advanceable over the shaft 820 and groove 852, retaining the support 844 within the groove 852. Retracting the sheath 850 allows the support 844 to spring back toward the pre-curved configuration, moving the trowel-shaped electrodes 830, 832, 834, and 836 radially outward, as shown. It will be appreciated that the amount of movement may be determined by the amount of retraction of the sheath 850. Maximum retraction allows maximum expansion of the trowel-shaped electrodes 830, 832, 834, and 836 to create lesions of maximum size. Smaller lesions can be created by gradually advancing the sheath 850 to desirably position the trowel-shaped electrodes 830, 832, 834, 836.

[0162]

[0198] It will be appreciated that there may be any suitable number of trowel-shaped electrodes, typically three, four, five, six, seven, eight, or more, and that the trowel-shaped electrodes may be activated independently, together, or in any combination, such as in pairs, groups, or sequential patterns of individual or grouped electrodes.

[0163]

[0199] It will also be appreciated that any portion of the trowel-shaped electrode may be insulated to focus energy delivery through a particular region. In this embodiment, the support portion 844 is insulated to direct energy through the triangular shaped portion of the trowel-shaped electrode. It will also be appreciated that various sensors may be positioned along the trowel-shaped electrode, such as microsensors for contact feedback or electroanatomical mapping systems. In this embodiment, such sensors are located along the base 844, but the sensors may be positioned along any suitable portion.

[0164]

[0200] FIG. 25 illustrates another embodiment of a treatment catheter 902. Here, the delivery electrode 922 comprises a single petal-, paddle-, or loop-shaped electrode 930 having a narrower shape near the shaft 920 and a larger, wider shape extending away from the shaft 920. In this embodiment, the electrode 930 lies in a plane aligned with the longitudinal axis 910 of the shaft 920. However, in this embodiment, the electrode 930 is made of a flexible material, which allows the electrode 930 to bend in various planes relative to the longitudinal axis 910, including perpendicular to the longitudinal axis 910. The bending of the electrode 930 allows the electrode 930 to be positioned from a variety of different approaches relative to various tissue surfaces. For example, the electrode 930 is not limited to approaching the target tissue from a generally perpendicular approach, but can also approach the target tissue from a parallel approach. Thus, the catheter 902 can be advanced along the tissue in a plane parallel to the tissue until the electrode 930 is positioned adjacent to the target tissue. The shaft 920 can then be angled away from the tissue so that the electrode 930 engages the tissue. Thereafter, the shaft 920 can be further angled away from the tissue to increase the engagement and / or contact force of the electrode 930 with the target tissue. This can be particularly useful when accessing tissue within a lumen, such as a pulmonary vein.

[0165]

[0201] In this embodiment, the catheter 902 further comprises a sensing loop 950, which is similar in shape to the single petal, paddle, or loop shaped electrode 930, as shown in FIG. 25, but is smaller so that it resides inside the loop shape of the electrode 930. In this embodiment, the sensing loop 950 has similar flexibility as the electrode 930 and can therefore function symmetrically with the electrode 930. Thus, in this embodiment, the sensing loop 950 and the electrode 930 are connected by a connector 952 to ensure that they remain substantially coplanar. The sensing loop 950 comprises one or more sensors 954, such as microsensors for contact feedback or an electroanatomical mapping system.

[0166]

[0202] 26A-26B illustrate another embodiment of a treatment catheter 1002 having a paddle-shaped delivery electrode 1022. Here, the delivery electrode 1022 comprises a single hammerhead paddle-shaped electrode 1030 having a narrower shape near the shaft 1020 and a wider hammerhead shape distal to the shaft 1020. In addition, the electrode 1030 includes multiple cross beams 1024 within the entire hammerhead shape, which provide support for the hammerhead paddle shape and additional area for energy delivery to create more solid lesions. In this embodiment, the electrode 1030 again lies in a plane aligned with the longitudinal axis 1010 of the shaft 1020. Finally, the electrode 1030 is made of a flexible material, which allows the electrode 1030 to bend in various planes relative to the longitudinal axis 1010, including perpendicular to the longitudinal axis 1010. In this embodiment, such bending is achieved through the use of a pull wire 1050 that extends at least partially through the shaft 1020 and is connected to a portion of the electrode 1030. Pulling the pull wire 1050 causes the electrode 1030 to bend into a plane that is at an angle to the longitudinal axis 1010, as shown in FIG. 26B. Thus, the electrode 1030 can be desirably positioned prior to contact with the target tissue. This separates positioning from the contact force applied during energy delivery.

[0167]

[0203] 27-30 illustrate another embodiment of a treatment catheter 1112. This embodiment is primarily configured for localized delivery of energy to a tissue surface, such as in a point-by-point manner. This is due to the shape and configuration of its delivery electrode 1122. FIG. 27 illustrates an embodiment of a treatment catheter 1112 in which the delivery electrode 1122 includes two semicircular loop electrodes 1130, 1132 that together form a circular or elliptical shape perpendicular to the shaft 1120. The electrodes 1130, 1132 are connected to the shaft 1120 by a support 1144, which is typically insulated to direct energy toward the semicircular electrodes 1130, 1132. In this embodiment, the delivery electrode 1122 further includes two additional sets of semicircular inner loops 1134, 1136 that together form a circular or elliptical shape with a smaller diameter than the two semicircular loop electrodes 1130, 1132. Thus, the two semicircular inner loops 1134, 1136 are "inside" the two semicircular loop electrodes 1130, 1132, both of which lie in a plane generally perpendicular to the shaft 1120. In this embodiment, the two semicircular loop electrodes 1130, 1132 and the two semicircular inner loops 1134, 1136 have an overall cup-like or concave shape. FIG. 28 provides a side view of the embodiment of FIG. 27, illustrating the cup-like shape. Similarly, FIG. 29 provides another side view, illustrating the position of the inner loops 1134, 1136 and loop electrodes 1130, 1132 relative to one another. In this manner, the inner loops 1134, 1136 and loop electrodes 1130, 1132 arc distally, and thus, advancing the catheter 1112 toward the target tissue location allows the loop electrodes 1130, 1132 to contact the tissue first, followed by the inner loops 1134, 1136. This ensures contact with the tissue of the loop electrodes 1130, 1132. Additionally, in some embodiments, the inner loops 1134, 1136 provide additional stability.For example, in some embodiments, the loop electrodes 1130, 1132 are made of a flexible material that allows the loop electrodes 1130, 1132 to flex proximally, thereby forming a less concave shape (e.g., a shallower cup shape, a flatter shape, or a more convex shape) to conform to the target tissue region. In some embodiments, the inner loops 1134, 1136 are made of a stiffer material than the loop electrodes 1130, 1132 to act as anchors during placement, providing greater confidence to the user. Additionally, the stiffer material resists bending more than the loop electrodes 1130, 1132, limiting the bending of the inner loop electrodes 1130, 1132. In some cases, this can be beneficial to avoid tissue perforation.

[0168]

[0204] FIG. 30 illustrates an end view of the delivery electrode 1122 of the embodiment of FIGS. 27-29. As shown, the loop electrodes 1130, 1132 are insulated along the support portion 1144 and exposed along the outer edge of the circular overall shape. In this embodiment, the inner loops 1134, 1136 include multiple microsensors 1160 spaced along the edge of the circular overall shape. In some embodiments, the microsensors 1160 are configured for contact feedback, visualization under fluoroscopy, or sensing for an electroanatomical mapping system. In other embodiments, the microsensors 1160 function as electrodes to deliver energy upon lesion formation. It will be appreciated that in some embodiments, the functionality of the microsensors 1160 alternates between various options, such as delivering energy upon delivery of energy through the loop electrodes 1130, 1132 and sensing during periods of energy delivery. It will also be appreciated that in some embodiments, the inner loops 1134, 1136 are comprised of a continuous conductive wire to provide energy delivery similar to the loop electrodes 1130, 1132.

[0169]

[0205] It will be appreciated that there may be any suitable number of loop electrodes 1130, 1132, typically one, two, three, four, five, six, seven, eight, or more. It will also be appreciated that the loop electrodes 1130, 1132 may be activated independently, together, or in any combination, such as in pairs, groups, or sequential patterns of individual or grouped electrodes. Similarly, there may be any suitable number of inner loops 1134, 1136, typically one, two, three, four, five, six, seven, eight, nine, ten, or more. Furthermore, there may be any suitable number of microsensors 1160, typically one, two, three, four, five, six, seven, eight, nine, ten, or more. It will be appreciated that the inner loops 1134, 1136 and / or microsensors 1160 may be activated independently, together, or in any combination, such as in pairs, groups, or sequential patterns of individual or group electrodes. In some cases, energy delivery via the inner loops 1134, 1136 assists in creating solid lesions rather than donut-shaped lesions. It will also be appreciated that the loop electrodes 1130, 1132 and inner loops 1134, 1136 may be activated independently, together, or in any combination, such as in pairs, groups, or sequential patterns of individual or grouped electrodes. It will also be appreciated that the loop electrodes 1130, 1132 may include microelectrodes, and energy is delivered through the microelectrodes rather than via conductive wires.

[0170]

[0206] As previously mentioned, the delivery electrodes 1122 are typically sized to deliver localized energy. In such embodiments, the loop electrodes 1130, 1132 form a circular shape with a diameter in the range of 8-14 mm. In other embodiments, the delivery electrodes 1122 are configured to provide one-shot delivery. In such embodiments, the loop electrodes 1130, 1132 form a circular shape with a diameter in the range of 22-33 mm.

[0171]

[0207] 31A-31D illustrate one embodiment of a treatment catheter 1202 configured for one-shot delivery rather than local delivery. Here, the treatment catheter 1202 includes a shaft 1220 that extends into a lumen, such as a pulmonary vein, upon placement of a delivery electrode 1222. Given this arrangement, the delivery electrode 1222 is configured to provide energy inwardly, outwardly, or both, circumferentially around the lumen in a "one-shot" energy delivery. It will be understood that this can be repeated as desired.

[0172]

[0208] In this embodiment, the energy delivery body or delivery electrode 1222 comprises a mesh basket configured to move between at least a collapsed configuration, an expanded configuration, and a partially inverted configuration. FIG. 31A illustrates the delivery electrode 1222 collapsed about the shaft 1220, on which the delivery electrode is mounted such that it can be housed within the sheath 1250. FIG. 31B illustrates the delivery electrode 1222 in an expanded configuration. This can be achieved by retracting the sheath 1250 or advancing the shaft 1220. In some embodiments, the delivery electrode 1222 self-expands upon release from the sheath 1250. In other embodiments, the mesh basket is coupled with an additional shaft that is movable relative to the shaft 1220, and advancement of the additional shaft expands the mesh basket.

[0173]

[0209] In some embodiments, the mesh basket is comprised of multiple wires that can be energized in unison, for example, to provide energy delivery in a monopolar manner. It will be appreciated that portions of the mesh basket may be insulated, thereby focusing energy delivery through certain non-insulated portions of the mesh basket. This may also help reduce energy loss to the surrounding blood environment. In other embodiments, multiple wires can be energized independently or in groups. This may also be used to provide energy delivery in a monopolar manner, or to deliver energy in a bipolar manner.

[0174]

[0210] Energy delivery electrodes 1222 may be utilized to deliver energy in this configuration. For example, the delivery electrodes 1222 may be positioned within the lumen to deliver energy circumferentially to the inner surface of the lumen. Alternatively, the delivery electrodes 1222 may be positioned relative to the opening of the lumen so that the distal surface of the mesh basket delivers energy circumferentially around the opening of the lumen. In either case, the diameter of the delivery electrodes 1222 may be selected or adjusted to desirably fit the anatomical structure, such as the pulmonary veins, of a particular patient by controlling the expansion of the mesh basket. Additionally, the flexibility of the mesh basket allows the delivery electrodes 1222 to conform to a range of circular and non-circular lumens or portions of anatomical structures.

[0175]

[0211] 31C-31D show further manipulation of the delivery electrode 1222 to move it into a partially inverted configuration. In some embodiments, this is accomplished by advancing the additional shaft further (i.e., beyond the expansion of the mesh basket), causing the mesh basket to begin to buckle as shown in FIG. 31C. Further advancement causes the mesh basket to partially invert, as shown in FIG. 31D, causing the distal surface of the mesh basket to maintain its funnel shape while the proximal surface of the mesh basket is inverted. Such inversion provides support for the distal surface and helps maintain the funnel shape, particularly during placement and delivery of energy to tissue.

[0176]

[0212] FIGS. 32A-32C illustrate one embodiment of a treatment catheter 1302 similar to that of FIGS. 31A-31D. The treatment catheter 1302 is again configured for one-shot delivery rather than localized delivery. And, in this embodiment, the delivery electrode 1322 comprises a wire basket somewhat similar to the mesh basket of FIGS. 31A-31D. The wire basket has a smaller surface area exposed to the blood and therefore more efficient energy delivery. In some embodiments, the wire basket is comprised of multiple wires that can be energized simultaneously, for example, to provide energy delivery in a monopolar manner. It will be appreciated that portions of the wire basket may be insulated, thereby focusing energy delivery through certain uninsulated portions of the wire basket. This may also help reduce energy loss to the surrounding blood environment. In other embodiments, multiple wires can be energized independently or in groups. This may also be used to provide energy delivery in a monopolar manner or to deliver energy in a bipolar manner.

[0177]

[0213] The treatment catheter 1302 is configured to move between at least a collapsed configuration, an expanded configuration, and a partially inverted configuration. Figure 32A illustrates the delivery electrode 1322 in a partially inverted configuration. Figure 32B illustrates the delivery electrode 1322 positioned relative to the opening of the lumen such that the distal face of the wire basket delivers energy around the opening of the lumen. Figure 32C illustrates the delivery electrode 1322 advanced into the lumen such that the distal face of the delivery electrode 1322 is positioned at least partially within the lumen.

[0178]

[0214] Again, the diameter of the delivery electrode 1322 can be selected or adjusted to desirably fit the anatomical structure, such as the pulmonary veins, of a particular patient by controlling the expansion of the wire basket. Additionally, the flexibility of the mesh basket allows the delivery electrode 1322 to conform to a range of circular and non-circular lumens or portions of anatomical structures.

[0179]

[0215] Figures 33A-33D illustrate one embodiment of a treatment catheter 1402 similar to that of Figures 31A-31D and 32A-32C. The treatment catheter 1402 is again configured for one-shot delivery rather than localized delivery. And, in this embodiment, the delivery electrode 1422 comprises a wire basket somewhat similar to the mesh basket of Figures 31A-31D and the wire basket of Figures 32A-32C. Here, the wire basket has an even smaller surface area exposed to blood and therefore provides more efficient energy delivery. This is achieved by the presence of legs or common supports 1430 on the distal and proximal surfaces of the wire basket, rather than woven wires. Because these portions typically align with the lumen, no contact area is required and energy can be focused on the woven portions of the wire basket.

[0180]

[0216] In some embodiments, the wire basket is comprised of multiple wires that can be energized in unison, for example, to provide energy delivery in a monopolar manner. It will be appreciated that portions of the wire basket may be insulated, thereby focusing energy delivery through certain non-insulated portions of the wire basket. This may also help reduce energy loss to the surrounding blood environment. In other embodiments, multiple wires can be energized independently or in groups. This may also be used to provide energy delivery in a monopolar manner, or to deliver energy in a bipolar manner.

[0181]

[0217] The treatment catheter 1402 is configured to move between at least a collapsed configuration, an expanded configuration, and a flattened configuration. FIG. 33A illustrates the delivery electrode 1422 folded around the shaft 1420, on which the delivery electrode is mounted so as to be housed within a sheath (not shown). FIG. 33B illustrates the delivery electrode 1422 in an expanded configuration. This can be achieved by retracting the sheath or advancing the shaft 1420 to reveal the wire basket. In some embodiments, the delivery electrode 1422 self-expands upon release from the sheath. In other embodiments, the wire basket is coupled with an additional shaft 1435 that is movable relative to the shaft 1420, and advancement of the additional shaft 1435 moves the supports 1430 together, expanding the wire basket.

[0182]

[0218] Energy delivery electrodes 1422 may be utilized to deliver energy in this configuration. For example, the delivery electrodes 1422 may be positioned within the lumen to deliver energy circumferentially to the inner surface of the lumen. Alternatively, the delivery electrodes 1422 may be positioned relative to the opening of the lumen so that the distal face of the wire basket delivers energy circumferentially around the opening of the lumen. In either case, the diameter of the delivery electrodes 1422 may be selected or adjusted to desirably fit the anatomical structure, such as the pulmonary veins, of a particular patient by controlling the expansion of the wire basket. Additionally, the flexibility of the wire basket allows the delivery electrodes 1422 to conform to a range of circular and non-circular lumens or portions of anatomy.

[0183]

[0219] 33C-33D illustrate further advancement of the additional shaft 1435 to move the delivery electrode 1422 into a flattened configuration. Here, the supports 1430 are fully gathered, thereby generally flattening the wire basket between the supports in a plane perpendicular to the shaft 1420, as shown in FIG. 33C. FIG. 33D provides a perspective view of the wire basket configuration depicted in FIG. 33C. Here, the wire basket can be seen to form a loop that extends radially outward, away from the supports 1430. The loop can deliver energy over a larger area than a single wire. The loop configuration is optimized to provide maximum coverage in the expanded position, while still being able to collapse against the shaft for delivery through a small introducer lumen.

[0184]

[0220] It will be appreciated that the delivery electrode 1422 can be positioned relative to the opening of a lumen, such as a pulmonary vein, in a manner such as that illustrated in Figure 32B. Similarly, the flexibility of the delivery electrode 1422 allows the delivery electrode 1422 to be advanced into the lumen such that a distal face of the delivery electrode 1422 is positioned at least partially within the lumen, in a manner such as that illustrated in Figure 32C.

[0185]

[0221] 34-38 and 39A-39B illustrate one embodiment of a treatment catheter 1502 configured for localized delivery. Here, the treatment catheter 1502 comprises a shaft 1504 having a distal end 1506 and an energy delivery body 1522 disposed near the distal end 1506. Here, the energy delivery body 1522 comprises a plurality of conductive splines 1524 that form a convex distal surface. Additionally, in this embodiment, the energy delivery body 1522 includes a distal tip electrode 1526. Here, the distal tip electrode 1526 is disposed along the center of the convex distal surface. This provides additional energy delivery to tissue over which the convex distal surface is positioned. This helps avoid potential areas of low or no energy delivery, which would create a donut-shaped lesion in the tissue. Thus, a continuous circular lesion is created.

[0186]

[0222] It will be appreciated that each spline 1524 can act as an electrode, and the splines can be energized simultaneously, independently, or in groups. Thus, in some embodiments, energy is delivered from all or a subset of the plurality of splines 1524 simultaneously, such that the energy delivery body 1522 delivers energy in a monopolar manner using at least one remote return electrode. Similarly, the distal tip electrode 1526 can be additionally energized simultaneously with the splines 1524 to deliver energy simultaneously in a monopolar manner. In other embodiments, energy is delivered between selected splines or between selected groups of splines, such that energy is delivered in a bipolar manner. Similarly, a combination of one or more splines 1524 and the distal tip electrode 1526 may be energized to deliver energy in a bipolar manner. Alternatively, energy may be delivered only from the tip electrode 1526 without energy delivery from one or more splines 1524, or vice versa, where energy is delivered from one or more splines 1524 but not from the tip electrode 1526. It will be appreciated that the splines 1524 may be wires, flat wires, struts, slabs, strips, or the like. In this embodiment, the splines 1524 are made of a shape-memory material such as nitinol flat wire. In this embodiment, the nitinol flat wire has a platinum core for improved visualization under fluoroscopy. In this embodiment, the plurality of splines 1522 are partially covered by an insulating material 1528. Here, the insulating material 1528 is located proximal to the energy delivery body 1522 so that energy impinging on the plurality of splines 1524 resists delivery through the insulating material 1528, directing the energy to the uninsulated portions of the plurality of splines 1522 facing distally. As a result, energy provided to the energy delivery body 1522 is focused in a distal direction. Because the distal convex surface can be positioned relative to the target tissue region, energy is efficiently directed toward the target tissue region without loss of energy from the proximal side of the energy delivery body 1522. This conserves energy and reduces energy sink into surrounding blood, etc.

[0187]

[0223] In this embodiment, the distal tip electrode 1526 is made of platinum-iridium and has a ball shape. It will be understood that other suitable materials may be used, and that other shapes may be used, such as flat, oval, or pointed. In some embodiments, the distal tip electrode 1526 facilitates guiding the treatment catheter 1502 to the target tissue region. This is accomplished by using the distal tip electrode 1526 to detect areas of active cardiac tissue that still require treatment. Thus, by reading an electrogram, subsequent placement of the catheter can be determined. In some embodiments, the distal tip electrode 1526 is used to record data, as described in a later section.

[0188]

[0224] The energy delivery body 1522 is transitionable between a collapsed configuration and an expanded configuration. FIG. 34 illustrates the energy delivery body 1522 in an expanded configuration. To collapse the energy delivery body 1522, a sheath or delivery tube can be advanced distally over the shaft 1504. As the sheath is advanced over the energy delivery body 1522, the flexibility of the splines 1524 allows the splines 1524 to straighten, thereby flattening the profile of the energy delivery body 1522 to fit within the sheath. Additionally, it will be appreciated that such straightening of the splines 1524 extends the distance between the distal tip electrode 1526 and the distal end 1506 of the shaft 1504. For this reason, the tip electrode wire 1530, which conducts energy through the shaft 1504 to the distal tip electrode 1526, is slack when the energy delivery body 1522 is in the expanded configuration shown in FIG. 34 . Such slack allows for extension when in the collapsed configuration.

[0189]

[0225] It will be appreciated that the catheter 1504 is delivered to the target treatment region within the body while the energy delivery body 1522 is collapsed and retained within a sheath, sleeve, or delivery device. Once positioned as desired within the body, the energy delivery body 1522 is then advanced from the sheath (or the sheath is retracted), thereby exposing the energy delivery body 1522. Such exposure allows the energy delivery body 1522 to self-expand to an expanded configuration. It will be appreciated that in other embodiments, the energy delivery body 1522 may be expanded by other mechanisms, such as by retraction of a plunger connected to the distal tip electrode 1526 or by expansion of a flexible expandable member (e.g., a balloon) within the energy delivery body 1522. However, the embodiment of FIG. 34 provides an energy delivery body 1522 that does not include a central shaft, creating a hollow, round cage. This allows for greater flexibility of the energy delivery body 1522. For example, pressing the convex distal surface against target tissue may cause the multiple splines 1524 to bend outward, increasing the diameter of the convex distal surface. Similarly, moving the shaft 1504 while keeping the convex distal surface stationary may allow an increase in force against the tissue in the direction of movement due to flexing of the splines 1524. For example, moving the shaft 1504 to the right during engagement may increase the engagement of the splines 1524 on the right side of the convex distal surface, allowing for greater force against this region of the tissue. Additionally, such increased flexibility may also allow the energy delivery body 1522 to be more easily steered, such as by bending more freely using pull wires, etc.

[0190]

[0226] FIG. 35 provides a side view of the embodiment of the treatment catheter 1502 of FIG. 34. Again, the splines 1524 are shown in an expanded configuration, with the energy delivery body 1522 forming a ball-shaped cage with a convex distal surface. In this embodiment, the splines 1524 are spaced apart in an evenly spaced circumferential array around a shaft plug 1532 in the shaft 1504. In this embodiment, each of the splines 1524 is connected to a conductive wire that extends through the shaft 1504 for connection to an energy generator. In this embodiment, the splines 1524 terminate around the distal tip electrode 1526 by curving and bending inward for attachment to the tip inner section 1534, as can be seen by referring again to FIG. 34. Thus, in this embodiment, the splines 1524 are evenly spaced in a circumferential array around the tip inner section 1534. The inward curvature and bending around the distal tip electrode 1526 creates a smooth distal surface for positioning against the target tissue.

[0191]

[0227] In this embodiment, the energy delivery body 1522 includes a sensing electrode 1540 positioned within the energy delivery body 1522 to avoid contact with the target tissue. In this embodiment, the sensing electrode 1540 is disposed proximal to (i.e., behind) the distal tip electrode 1526 within a rounded cage of multiple splines 1524. Here, the sensing electrode 1540 comprises a ring electrode, such as a single 0.030" ring electrode, extending around the tip inner portion 1534. In this embodiment, additional electrodes 1542, 1544, such as two 0.070" ring electrodes, are disposed along the shaft 1504 proximal to the energy delivery body 1522. In this embodiment, the electrodes 1540, 1542, 1544 are made of platinum-iridium and also serve as marker bands for visualization under fluoroscopy.

[0192]

[0228] The sensing electrode 1540 and additional electrodes 1542, 1544 are typically used to sense ECG signals and also to provide information to an electroanatomical mapping system. For example, upon sensing an ECG signal, a user can verify or confirm the location of the treatment catheter 1502 within the heart based on the sensed ECG signal. When approaching a ventricle, the user may verify such approach by checking for an increase in the amplitude of the ventricular signal. Similarly, impedance measurements are optionally tracked by the sensing electrode 1540 and / or the additional electrodes 1542, 1544. The electroanatomical mapping system uses such impedance measurements to visualize the location of these electrodes 1540, 1542, 1544 within the heart, and therefore the location of the treatment catheter 1502.

[0193]

[0229] 35, this embodiment also includes a steering mechanism. In this embodiment, the steering mechanism comprises a pull ring 1560 disposed along the shaft 1504. The pull ring 1560 is connected to one or more pull wires. In this embodiment, the pull ring 1560 is connected to a first pull wire 1562a and a second pull wire 1562b, with the pull wires 1562a and 1562b attached to opposite ends of the pull ring 1560. The pull wires 1562a and 1562b extend toward the proximal end of the shaft 1504 so that the distal end 1506 can be remotely manipulated. Pulling the first pull wire 1562a causes the distal end 1506 and therefore the energy delivery body 1522 to bend in the direction of the first pull wire 1562a (e.g., to the left), and pulling the second pull wire 1562b causes the distal end 1506 and therefore the energy delivery body 1522 to bend in the direction of the second pull wire 1562b (e.g., to the right). It will be understood that there can be any suitable number of pull wires for steering in various directions. Similarly, other steering mechanisms may be used instead of or in addition to the steering mechanisms described herein.

[0194]

[0230] FIG. 36 illustrates a bottom view of the treatment catheter 1502 of FIGS. 34-35 , facing the convex distal surface of the energy delivery body 1522. As shown, in this embodiment, the energy delivery body 1522 includes ten splines 1524, although any suitable number of splines 1524 may be present, including one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, or more. Here, the distal portion of each spline 1524 extends radially outward from the distal tip electrode 1526 and then curves back proximally, forming a ball, sphere, or rounded cage shape. Thus, each of these spline surfaces is uninsulated and delivers energy to tissue. In this embodiment, an angle θ is formed between each spline 1524, and thus each angle θ is 36 degrees. It will be appreciated that angle θ will vary depending on the number of splines 1524, but such angle θ will typically be in the range of 10 to 45 degrees, such as 10 to 20 degrees, 20 to 30 degrees, or 30 to 45 degrees. With fewer splines 1524, such angle θ may increase to 50 degrees, 60 degrees, 70 degrees, 80 degrees, or 90 degrees, etc.

[0195]

[0231] FIG. 37 provides another perspective view of the embodiment of FIG. 34 . In this view, irrigation ports 1570 are visible along the distal face of the shaft plug 1532. The irrigation ports 1570 are positioned to deliver irrigation fluid to the proximal end of the energy delivery body 1522 to allow flow toward the distal end of the energy delivery body 1522 (i.e., toward the tip medial portion 1534 and the distal tip electrode 1526). Such irrigation helps reduce the likelihood of blood clot formation along the energy delivery body 1522. In some cases, blood clotting may be more likely between elements such as closely spaced splines 1524 positioned in blood-filled areas. As illustrated in FIG. 37 , the distance between the splines 1524 tapers toward the proximal end of the energy delivery body 1522 and toward the distal end of the energy delivery body 1522. Such areas are more prone to blood clotting due to increased blood stagnation in these areas. Stagnant blood may clot and pose a risk to the patient. The use of a flow of irrigation fluid, such as saline, in and around the splines 1524 reduces the likelihood of blood clot formation.

[0196]

[0232] It will be appreciated that the desired irrigation fluid flow will be sufficient to reach all or most of the area that may be filled with stagnant blood around the splines 1524. In some embodiments, this is achieved through the use of multiple irrigation ports 1570 configured to create turbulent flow within the hollow cage of the energy delivery body 1522. While a single irrigation lumen may provide a fluid flow output large enough to reach the proximal end of the energy delivery body 1522, this flow may not be strong enough to reach the distal end of the energy delivery body 1522. However, passing fluid through multiple irrigation ports 1570 into a single irrigation lumen creates turbulence in the flow at the proximal end of the energy delivery body 1522, which continues in a wide fan of fluid flow to the distal end of the energy delivery body 1522. The wide fan also accounts for the coverage area of ​​the energy delivery body 1522 when the energy delivery body 1522 is bent or moved laterally during positioning or manipulation. It will be appreciated that such turbulent flow can also be achieved through the use of multiple irrigation lumens. Typically, the number of irrigation lumens is fewer than the number of irrigation ports to deliver sufficient flow while still creating turbulence. FIG. 38 provides an enlarged view of a portion of the distal end 1506 of the shaft 1504 of the treatment catheter 1502. Here, the shaft 1504 has been removed to reveal the shaft plug 1532 with splines 1524 disposed thereabout. A conductive wire 1525 is shown connected to each spline 1525. The conductive wire 1525 extends proximally along the shaft 1504 for connection to the generator 108 to deliver energy to the splines 1525. The embodiment of FIG. 38 includes two irrigation lumens 1580 that deliver fluid to the irrigation ports 1570. Here, there are five irrigation ports 1570. It will be appreciated that there may be a variety of irrigation lumens 1580, including one, two, three, four, five, six, or more. Similarly, there may be a variety of irrigation ports 1570, including one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, or more. However, due to turbulence, the irrigation ports 1570 will typically outnumber the irrigation lumens 1580.

[0197]

[0233] Figures 39A-39B provide additional illustrations of the embodiment of Figure 34. Figure 39A provides an exploded view of the elements comprising this embodiment of a treatment catheter 1502. As shown, this embodiment includes a distal tip electrode 1526, a tip medial section 1534, a tip electrode wire 1530, an energy delivery body 1522 comprising a plurality of splines 1524 at least partially covered by an insulating material 1528, a retaining band 1590, a shaft plug 1532, a solder plate 1592, an adhesive potting 1594, a pull ring 1560, an irrigation lumen 1580, a shaft 1504 comprising electrodes 1542, 1544, and a shaft tip section 1596. Figure 39B illustrates the treatment catheter 1502 of Figure 39A in an undeployed state.

[0198]

[0234] As previously mentioned, the treatment catheter 1502 is described as a local therapy device designed to create lesions larger than the footprint of a solid-tip treatment catheter, such as that shown in FIGS. 2A-2B, but smaller than the footprint of a one-shot device. In some embodiments, the shaft 1504 of the treatment catheter 1502 is 8 French (2.67 mm) and is delivered using an 8.5 French (2.83 mm) sheath. In such embodiments, the energy delivery body 1522 is configured to fit within the 8.5 French sheath in a collapsed configuration and thus has an outer diameter of less than 2.83 mm. When the energy delivery body 1522 is released to its expanded state, the outer diameter typically expands to 8-15 mm, which is 3-6 times the diameter of the shaft 1504. It will be appreciated that the footprint of such devices may vary in dimensions within this range, including 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 8-10 mm, 9-10 mm, 9-15 mm, 10-15 mm, 12-15 mm, etc.

[0199] Sensors and Irrigation

[0235] The tissue modification system 100 described herein delivers a series of PEF batches or bundles as described herein over a period of time, such as a few seconds. This accumulation of energy deposition results in a small amount of Joule heating, which is inherent in all PEF therapies because it is a by-product of energy deposition. However, acute, subacute, intermediate-term, and long-term histological data all demonstrate substantial absence of evidence of thermal damage to tissue using the systems, devices, and methods described herein. Thus, it is clear that no thermal damage (extracellular protein denaturation) occurs in cardiac tissue, reducing the likelihood of treatment-related adverse events, such as pulmonary vein stenosis, and anatomical defects. This also eliminates the creation of surface charring or thermal damage, which would interfere with energy delivery to the underlying tissue and reduce the ability to create transmural lesions.

[0200]

[0236] However, it will be understood that in some embodiments, system 100 includes temperature sensing and / or control measures for various purposes. In some embodiments, temperature is sensed and controlled to ensure that the temperature remains within a range of 30-65°C, 30-60°C, 30-55°C, 30-50°C, 30-45°C, or 30-35°C. Thus, the tissue temperature remains below the thermal ablation threshold, and lesions are not created by thermal damage. In some embodiments, one or more temperature sensors are used to measure electrode and / or tissue temperature during treatment to ensure that the energy applied to the tissue does not result in clinically significant tissue heating. For example, in some embodiments, temperature sensors monitor the tissue and / or electrode temperature, and if it exceeds a predefined threshold temperature (e.g., 65°C), the generator modifies an algorithm to automatically cease energy delivery or to allow the temperature to drop below the predefined threshold. For example, in some embodiments, if the temperature exceeds 65°C, the generator decreases the pulse width or increases the time between pulses and / or packets (e.g., delivers energy every other heartbeat, every third heartbeat, etc.) in an attempt to reduce the temperature. This may be done in a predefined stepwise approach as a parameter percentage, or by other methods. It will be appreciated that the temperature sensor may be positioned on the electrode, adjacent to the electrode, or at any suitable location along the distal portion of the catheter. Alternatively or additionally, the sensor may be positioned on one or more separate devices.

[0201]

[0237] In other embodiments, temperature is sensed to assess lesion formation. This can be particularly useful when creating lesions in anatomical structures with target tissue regions of different thicknesses. A sudden increase in temperature indicates that the lesion has penetrated deeper into the tissue and is nearing completion. Sensing such changes in temperature can be particularly useful when creating lesions in thicker tissue or tissue of unknown depth.

[0202]

[0238] In some embodiments, the treatment catheter includes irrigation to help control the temperature of the delivery electrode or surrounding tissue. In some cases, the irrigation cools the delivery electrode, allowing for more PEF delivery per unit time without increasing the likelihood of heat-mediated damage. In some cases, the irrigation also reduces or prevents clotting near the tip of the catheter. It will be appreciated that irrigation can be activated, increased, decreased, or stopped based on information from one or more sensors, particularly one or more temperature sensors.

[0203]

[0239] Such cooling is achieved by delivering a fluid, such as isotonic saline, through the lumen of the catheter, through one or more irrigation ports, and exiting along the distal end of the catheter. The fluid may be chilled, room temperature, or warmed. Fluid flow may be driven by a variety of mechanisms, including gravity-driven drip, peristaltic pumps, centrifugal pumps, and the like. In some embodiments, irrigation has a flow rate of 0.1 to 10 ml / min, including 1 ml / min, 2 ml / min, 3 ml / min, 4 ml / min, 5 ml / min, or more. In some embodiments, the flow rate is sensed by an electrical or mechanical flow sensing mechanism. In some embodiments, the temperature of the fluid is measured, and in other embodiments, the temperature of the fluid is modified, such as by heating or cooling, as the fluid is pumped into the treatment catheter, such as based on the measured temperature. In some embodiments, the fluid flow rate is determined based on the measured temperature of the tissue to be treated.

[0204]

[0240] In some embodiments, the pump is in electrical communication with the generator 108, and the fluid flow rate is modified by the generator 108 based on the status of energy delivery to the treatment catheter 102. For example, in some embodiments, the fluid flow rate is increased during energy delivery. Similarly, in some embodiments, the fluid flow rate is increased by a predetermined amount up until a time prior to energy delivery and / or at one or more predetermined times during energy delivery. Alternatively, or additionally, the fluid flow may be controlled in response to a user request. It will be appreciated that the pump may be in communication with the generator 108 to operate at different speeds based on various aspects of the energy delivery algorithm 152. In some embodiments, sensing of the flow rate and communication with the generator 108 is used to prevent energy delivery if irrigation is not occurring. In other embodiments, the selection of the energy delivery algorithm 152, in turn, selects a fluid flow rate appropriate for the energy delivery algorithm 152. In some embodiments, at least one irrigation port is located along the electrode and / or, optionally, at least one irrigation port is located along the shaft.

[0205]

[0241] It will be understood that any of the catheter designs described herein may include one or more sensors (e.g., microsensors), such as impedance sensors, contact sensors, contact force sensors, electroanatomical mapping sensors, etc. Such sensors may be positioned on the electrodes, adjacent to the electrodes, or at any suitable location along the distal portion of the catheter. For example, a microsensor may be located along one or more loops of a delivery electrode or along a support structure near a delivery electrode. Alternatively or additionally, the sensors may be positioned on one or more separate devices.

[0206]

[0242] While the various delivery electrodes have been described as being conductive wires from which energy can be delivered, it will be appreciated that such designs may also utilize individual electrodes (e.g., microelectrodes) spaced along non-conductive wires. Optionally, such electrodes may be spaced along a conductive wire when the conductive wire is insulated from the electrode where the electrode is attached.

[0207]

[0243] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only the elements shown or described are provided. The inventors also contemplate examples that use any combination or permutation of the elements shown or described (or one or more aspects thereof), with respect to a particular example (or one or more aspects thereof), or with respect to any other example (or one or more aspects thereof) shown or described herein.

[0208]

[0244] In the event of a conflict in terminology between this specification and any document incorporated by reference, the terminology in this specification will control.

[0209]

[0245] As used herein, the terms "a" or "an," as is common in patent documents, are used to include one or more, regardless of any other instance or usage of "at least one" or "one or more." As used herein, the term "or" is used to refer to a non-exclusive, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. As used herein, the terms "including" and "in which" are used as the plain-English equivalents of the terms "comprising" and "wherein," respectively. Also, in the following claims, the terms "including" and "comprising" are open-ended; that is, systems, devices, articles, compositions, formulations, or processes that include elements in addition to those recited after such terms in a claim are still considered to be within the scope of that claim. Moreover, in the following claims, terms such as "first," "second," and "third" are used merely as labels and are not intended to impose numerical requirements on their objects.

[0210]

[0246] The above description is intended to be illustrative, not limiting. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be utilized, for example, by one of ordinary skill in the art upon review of the above description. The Abstract is provided in accordance with 37 CFR §1.72(b) to allow the reader to quickly ascertain the nature of the technical disclosure. The Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be construed as intending that any unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may reside in less than all features of a particular disclosed embodiment. Thus, it is contemplated that the following claims are incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. A device for delivering energy to cardiac tissue of a patient, comprising: a shaft having a proximal end and a distal end; an energy delivery body located at the distal end of the shaft, the energy delivery body comprising a plurality of shape memory splines and transitionable between a collapsed configuration and an expanded configuration, wherein in the expanded configuration, the plurality of shape memory splines form a convex distal surface positionable against the cardiac tissue to deliver energy to the cardiac tissue; A device comprising:

2. The device described in claim 1, wherein the plurality of shape memory splines form a round cage having the convex distal surface in the expanded configuration.

3. The device described in claim 2, wherein the round cage is supported only by the plurality of shape memory splines.

4. The device described in claim 3, wherein the energy delivery body includes a distal tip electrode, and the plurality of shape memory splines support a tip electrode wire extending from the distal tip electrode to the shaft, which is otherwise hollow.

5. A device described in any one of claims 2 to 4, wherein the round cage is flexible so as to deform when positioned relative to the cardiac tissue.

6. A device described in any one of claims 2 to 5, wherein the round cage is flexible so as to at least partially flatten when positioned against the cardiac tissue.

7. The device described in claim 1, wherein the convex distal surface is configured to have a footprint of 8 to 15 mm when positioned against the cardiac tissue to deliver energy to the cardiac tissue.

8. The device described in claim 1, wherein the multiple shape memory splines can be energized simultaneously to function in a unipolar manner.

9. The device described in claim 1, wherein the energy delivery body includes a distal tip electrode arranged along the convex distal surface.

10. The device described in claim 9, wherein the distal tip electrodes are independently energizable.

11. A device described in any one of claims 1 to 10, wherein at least a portion of the energy delivery body is insulated to direct the energy through the convex distal surface.

12. A device described in any one of claims 1 to 11, further comprising at least one irrigation lumen and a plurality of irrigation ports.

13. The device described in claim 12, wherein the at least one irrigation lumen has a number of irrigation lumens that is fewer than the number of irrigation ports.

14. The device described in claim 2, wherein the energy delivery body is electrically connected to a generator to deliver pulsed electric field energy to the cardiac tissue.

15. The device of claim 1, wherein the energy delivery body is configured to transition from the collapsed configuration to the expanded configuration by self-expansion of the plurality of shape memory splines in response to release of the energy delivery body from a sheath that constrains the plurality of shape memory splines.

16. The device described in claim 1, wherein the plurality of shape memory splines are insulated along their proximal portions.

17. The device described in claim 1, further comprising a distal inner portion, each of the plurality of shape memory splines attached to the distal inner portion, the distal inner portion positioned proximal to the curved distal ends of the plurality of shape memory splines.

18. The device described in claim 17, further comprising a distal tip electrode, wherein the plurality of shape memory splines are curved and bent inwardly around the distal tip electrode, which is located distal to the curved distal ends of the plurality of shape memory splines.

19. The device described in claim 17, further comprising a sensing electrode positioned within the energy delivery body proximal to the curved distal ends of the plurality of shape memory splines.

20. The device of claim 19, wherein the sensing electrode comprises a ring electrode extending around the inner tip portion.

21. The device described in claim 18, further comprising a tip electrode wire electrically connected to the distal tip electrode and extending within the energy delivery body from the distal end of the shaft to the distal tip electrode.

22. The device described in claim 21, wherein the tip electrode wire is slack when the energy delivery body is in the expanded configuration.

23. The device described in claim 1, wherein each of the plurality of shape memory splines is conductive and functions as an electrode.

24. The device described in claim 1, wherein the plurality of shape memory splines extend distally beyond the distal end of the shaft in both the collapsed configuration and the expanded configuration.

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