Planar end effector for atrial fibrillation ablation using pulsed-field ablation

Abstract

To provide a catheter configured to ablate tissue by pulsed-field ablation. [Solution] A catheter is presented having a planar end effector with elongated ablation electrodes configured to provide electrical signals to achieve IRE in target tissue. The planar end effector may be aligned along the longitudinal axis of the catheter shaft and configured to bend away from the longitudinal axis when in contact with tissue. Bipolar electrical signals may be applied between the elongated ablation electrodes in various pair combinations to achieve PFA. The end effector may also include a diagnostic electrode configured to receive electrical signals from the tissue and map the tissue, a pair of tissue contact electrodes to determine which part of the end effector is in contact with the tissue, or a reference electrode configured to measure blood voltage.

Description

Technical Field

[0001] The present invention generally relates to medical devices, and more particularly to a catheter configured to ablate tissue by pulsed field ablation.

Background Art

[0002] Cardiac arrhythmias such as atrial fibrillation (AF) occur when areas of cardiac tissue conduct electrical signals abnormally to adjacent tissue. This disrupts the normal cardiac cycle and causes asynchronous rhythms. Arrhythmias are treated surgically or by catheter ablation to stop or alter the propagation of unwanted electrical signals from one part of the heart to another.

[0003] Many current ablation approaches utilize radiofrequency (RF) electrical energy to heat tissue. RF ablation has certain rare drawbacks due to operator skill, such as an increased risk of thermal cell damage that can cause tissue carbonization, charring, steam pops, phrenic nerve paralysis, pulmonary vein stenosis, and esophageal fistulas. Cryoablation is an alternative approach to RF ablation that reduces some of the thermal risks associated with RF ablation, but can present tissue damage due to the ultra-low temperature nature of such devices. Operating a cryoablation device to selectively apply cryoablation is generally more difficult compared to RF ablation, and thus cryoablation may not be feasible in certain anatomical shapes that can be reached by RF ablation devices.

[0004] Pulsed-field ablation (PFA) is a relatively new non-thermal method for ablating cardiac tissue by inducing irreversible electroporation (IRE) in the cells of a target tissue. To achieve IRE, short pulses of high-voltage electrical signals are delivered to the tissue, and the electrical signals cause irreversible permeabilization of the cell membrane. Examples of systems and devices configured for IRE ablation are described in U.S. Patent Applications Publications 2021 / 0169550(A1), 2021 / 0169567(A1), 2021 / 0169568(A1), 2021 / 0196372(A1), 2021 / 0177503(A1), and 2021 / 0186604(A1), and U.S. Patent No. 11,540,877, each of which is incorporated herein in whole by reference and attached to the appendices herein.

[0005] Areas of cardiac tissue can be mapped by catheters to identify abnormal electrical signals. Some catheter ablation procedures, particularly those involving persistent atrial fibrillation, may be performed using electrophysiological (EP) mapping to target areas of abnormal electrical signals. Such EP mapping may involve the use of diagnostic electrodes configured to monitor electrical signals within the cardiovascular system to precisely indicate the location of abnormal conductive tissue sites involved in arrhythmias. An example of an EP mapping system is described in U.S. Patent No. 5,738,096, which is incorporated herein by reference in its entirety. Examples of EP mapping catheters are described in U.S. Patent No. 9,907,480, U.S. Patent Publication No. 2018 / 0036078, and U.S. Patent Publication No. 2018 / 0056038, each of which is incorporated herein by reference in its entirety.

[0006] In addition to using EP mapping, some catheter ablation procedures may be performed using image-guided surgery (IGS) systems. IGS systems can allow physicians to visually track the catheter's position within the patient in real time in relation to images of the patient's anatomical structures. Some systems, including the CARTO 3® system by Biosense Webster, Inc. (Irvine, California), can offer a combination of EP mapping and IGS capabilities. [Overview of the project] [Means for solving the problem]

[0007] A catheter is presented having a planar end effector with elongated ablation electrodes configured to provide electrical signals to achieve IRE in target tissue. The planar end effector may be aligned along the longitudinal axis of the catheter shaft and configured to bend away from the longitudinal axis upon contact with tissue. Bipolar electrical signals may be applied between the elongated ablation electrodes in various pair combinations to achieve PFA. The end effector may also include a diagnostic electrode configured to receive electrical signals from the tissue and map the tissue, a pair of tissue contact electrodes to determine which part of the end effector is in contact with the tissue, a reference electrode configured to measure blood voltage, or a combination thereof. The end effector may provide PFA to create a wound having a depth of approximately 7.5 mm in a potato model.

[0008] An exemplary end effector of a medical probe includes a planar body and a plurality of ablation electrodes. The planar body has a first side and a second side opposite to the first side and extends along its longitudinal axis. The plurality of ablation electrodes include a first ablation electrode and a second ablation electrode located on the first side of the planar body. The end effector is configured to provide a bipolar pulsed-field ablation electrical signal between the first ablation electrode and the second ablation electrode. The first ablation electrode and the second ablation electrode each have a length of at least half the total length of the end effector when measured from the distal end of the end effector to the distal end of the shaft of the medical probe. The respective lengths of the first ablation electrode and the second ablation electrode define the distal portion of the end effector.

[0009] An exemplary method for providing a PFA electrical signal to a planar end effector includes providing a first bipolar pulsed field ablation electrical signal between a first ablation electrode and a second ablation electrode, wherein the first ablation electrode is positioned on the first side of the planar body of the planar end effector, and the second ablation electrode is positioned on the second side of the planar body and does not overlap with the first ablation electrode; and using the planar end effector to create damage in a potato model having a depth of approximately 7.5 mm. [Brief explanation of the drawing]

[0010] This specification concludes with claims that specifically identify and assert rights to the subject matter described herein, which is better understood from the following description of specific embodiments taken in conjunction with the accompanying drawings. In the drawings, similar reference numerals identify the same elements. The drawings depict one or more implementations of the device of the present invention, not as limitations but merely as examples. [Figure 1] This figure shows an exemplary catheter-based electrophysiological mapping and ablation system. [Figure 2] This is a diagram of the distal portion of a catheter, including an exemplary end effector. [Figure 3] Figure 2 is a magnified view of an exemplary end effector. [Figure 4] This is a diagram of a first exemplary electrode configuration of an exemplary end effector, including an elongated, serpentine ablation electrode and a diagnostic electrode positioned along the ablation electrode. [Figure 5] The diagram shows a second exemplary electrode configuration of an exemplary end effector, each including an elongated ablation electrode segmented into small parallel stripes and a diagnostic electrode positioned along the ablation electrode. [Figure 6] This is a diagram of a third exemplary electrode configuration for an exemplary end effector, which includes a rectangular, elongated ablation electrode without a diagnostic electrode. [Figure 7] This is a diagram of a fourth exemplary electrode configuration of an exemplary end effector, which includes a rectangular, elongated ablation electrode interrupted by a diagnostic electrode. [Figure 8] This diagram shows an exemplary electrode configuration on one side of an exemplary end effector, including elongated ablation electrodes in two ablation electrode regions, a diagnostic electrode positioned within the two ablation electrode regions, a tissue contact electrode positioned between the two ablation electrode regions, and a reference electrode positioned within the proximal region on the illustrated side of the end effector. [Figure 9A] Figure 9A shows alternative configurations of insulating materials in the cross-section of the end effector, where it is configured with an opening within the end effector as shown in Figure 8. Figure 9B includes a polymer body region extending across the width of the end effector. Figure 9C includes a high dielectric layer between each side and extending across the width of the end effector, and Figure 9D includes high dielectric tiles between each side and configured to overlap to fold the end effector into the delivery sheath. [Figure 9B]Figure 9A shows alternative configurations of insulating materials in the cross-section of the end effector, where it is configured with an opening within the end effector as shown in Figure 8. Figure 9B includes a polymer body region extending across the width of the end effector. Figure 9C includes a high dielectric layer between each side and extending across the width of the end effector, and Figure 9D includes high dielectric tiles between each side and configured to overlap to fold the end effector into the delivery sheath. [Figure 9C] Figure 9A shows alternative configurations of insulating materials in the cross-section of the end effector, where it is configured with an opening within the end effector as shown in Figure 8. Figure 9B includes a polymer body region extending across the width of the end effector. Figure 9C includes a high dielectric layer between each side and extending across the width of the end effector, and Figure 9D includes high dielectric tiles between each side and configured to overlap to fold the end effector into the delivery sheath. [Figure 9D] Figure 9A shows alternative configurations of insulating materials in the cross-section of the end effector, where it is configured with an opening within the end effector as shown in Figure 8. Figure 9B includes a polymer body region extending across the width of the end effector. Figure 9C includes a high dielectric layer between each side and extending across the width of the end effector, and Figure 9D includes high dielectric tiles between each side and configured to overlap to fold the end effector into the delivery sheath. [Figure 10] This is a diagram of an end effector configured so that the ablation electrode provides a 1,200V pulse between the ablation electrode regions. [Figure 11] Figure 10 shows an end-effector applying the treatment shown to the potato model. [Figure 12A] For each pair, one ablation electrode is in contact with the tissue, and the other electrode is on the opposite side of the end effector body. The voltage applied is shown across the cross-body electrode pair, which runs from the first electrode region across the central axis of the end effector body. Figures 12A and 12B show two different electrode pairs. [Figure 12B]For each pair, a voltage is applied across an electrode pair of a cross-body configuration where one ablation electrode contacts tissue and the other electrode is on the opposite side of the end effector body and crosses the central axis of the end effector body from the first electrode region. FIGS. 12A and 12B show two different electrode pairs. [Figure 12C] Shows the voltage applied between electrode segments that function as separately actuated electrodes. [Figure 13] Shows the voltage applied across an ablation electrode pair where both ablation electrodes of the pair contact tissue and are arranged across the central axis from each other. [Figure 14] Shows the voltage applied from an ablation electrode in contact with tissue to an ablation electrode on the opposite side of the end effector that is not in contact with tissue. [Figure 15A] Illustrates the voltage applied across an electrode pair where the pair of electrodes are arranged across the central axis from each other. [Figure 15B] Illustrates the voltage applied across an electrode pair where the pair of electrodes are arranged across the central axis from each other. [Figure 16] FIG. is a diagram of an exemplary electrode configuration on one side of an exemplary end effector, including elongated ablation electrodes in four ablation electrode regions, diagnostic electrodes disposed in at least two of the ablation electrode regions, tissue contact electrodes disposed along the longitudinal axis between the ablation electrode regions, and a reference electrode disposed in the proximal region on the illustrated side of the end effector. [Figure 17] FIG. is a diagram of an exemplary electrode configuration of an exemplary end effector including an elongated serpentine ablation electrode. [Figure 18] FIG. is a diagram of an exemplary electrode configuration of an exemplary end effector including a rectangular elongated ablation electrode. [Figure 19] FIG. is a diagram of an exemplary electrode configuration of an exemplary end effector including a large area ablation electrode. [Figure 20]FIG. is a diagram of an exemplary electrode configuration of an exemplary end effector in which an ablation electrode wraps around the spine of a catheter body or around an insulating material. [Figure 21] FIG. is a diagram of an exemplary electrode configuration of an exemplary end effector in which an ablation electrode partially wraps around the spine of a catheter body or around an insulating material. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following detailed description should be read with reference to the drawings, and like elements in different drawings are numbered the same. The drawings are not necessarily to scale and depict selected embodiments and are not intended to limit the scope of the invention. The detailed description is illustrative, not limiting, and is presented by way of example to illustrate the principles of the invention. This specification enables one skilled in the art to make and use the invention and describes some embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently considered to be the best mode for carrying out the invention. Any material incorporated herein by reference includes similar terms, but the definitions and descriptions provided herein are understood to be used to understand the technology of the present disclosure herein, unless the definitions or descriptions are different.

[0012] As used herein, the term "about" or "approximately" with respect to any numerical value or range indicates a preferred dimensional tolerance that allows a part or collection of components to function for the intended purpose described herein. More specifically, "about" or "approximately" may refer to a range of values within ±20% of the recited value. For example, "about 90%" may refer to a range of values from 71% to 110%.

[0013] In addition, as used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject, and the use of the invention in human patients represents a preferred embodiment, but is not intended to limit the system or method to human use.

[0014] Similarly, the term "proximal" refers to a location closer to the operator, while "distal" refers to a location further away from the operator or physician.

[0015] As discussed herein, “operator” and “user” may include physicians, surgeons, technicians, scientists, or any other individuals or delivery devices associated with the delivery of the multi-electrode catheter for the treatment disclosed herein.

[0016] As discussed herein, when the terms “bipolar” and “monopole” are used to refer to ablation schemes, they describe different IRE ablation schemes with respect to current paths and electric field distributions. “Bipolar” refers to an IRE ablation scheme that utilizes a current path between two electrodes placed near the ablation site or inside the organ being treated, where the current density and electric flux density are typically, but not necessarily, approximately equal in each of the two electrodes. “Monopole” refers to an IRE ablation scheme that utilizes a current path between two electrodes, where one electrode with high current density and high electric flux density is placed at the ablation site, and a second electrode with relatively low current density and lower electric flux density is placed at a distance from the ablation site, usually outside the body, such as on a patch on the patient's skin.

[0017] As discussed herein, the terms “biphasic pulse” and “monophase pulse” refer to the respective electrical signals. A “biphasic pulse” refers to an electrical signal having a positive voltage phase pulse (referred to herein as the “positive phase”) and a negative voltage phase pulse (referred to herein as the “negative phase”). A “monophase pulse” refers to an electrical signal having only a positive phase or only a negative phase. Preferably, the system providing the biphasic pulse is configured to prevent the application of direct current (DC) to the patient. For example, the average voltage of the biphasic pulse may be zero volts relative to ground or other common reference voltage. Each phase of the biphasic and monophasic pulses preferably has a square shape with an essentially constant voltage amplitude for most of the phase duration. The phases of the biphasic pulse may be temporally separated by an interphase delay.

[0018] Features of alternative devices and systems, as well as alternative method steps, are presented in the exemplary embodiments herein. Each given exemplary embodiment presented herein may be modified to include features or method steps presented together with other exemplary embodiments herein, but such features or steps are interchangeable with the given embodiments as understood by those skilled in the art and as expressly stated herein. Such modifications and variations are intended to be included within the scope of the claims.

[0019] A catheter is presented having a planar end effector with an elongated ablation electrode configured to provide an electrical signal to achieve IRE in target tissue. The planar end effector may be aligned along the longitudinal axis of the catheter shaft and configured to bend away from the longitudinal axis upon contact with tissue. In some embodiments, the catheter fits with an 8.5 French sheath. In some embodiments, the end effector includes a highly insulating layer separating the electrodes on both sides of the end effector. To facilitate folding of the highly rigid insulator, in some embodiments, the highly insulating layer includes tiles of insulating material that overlap when the end effector is retracted into the sheath.

[0020] In some embodiments, the end effector includes four elongated electrode segments on each side of the end effector (a total of eight elongated electrode segments). The elongated electrode segments extend from near the distal end of the end effector to about half or more of the length of the end effector when measured from the distal end to the proximal end of the end effector. The end effector may include two electrode regions per side of the end effector (a total of four electrode regions), each electrode region including two of the elongated electrode segments connected within the end effector to function as a single electrode. Alternatively, each electrode segment may be divided approximately in half, resulting in twice the number of elongated electrode segments, each longer than half of the aforementioned elongated electrode segments. This embodiment may include four electrode regions per side of the end effector, a total of eight electrode regions.

[0021] An electrical signal, including pulses to achieve IRE, can be applied between electrode pairs to achieve PFA. Ablation electrodes can be paired in various ways, and pulses can be applied between different pairs in the same PFA treatment. In some embodiments, an end effector can provide PFA to create a wound having a depth of approximately 7.5 mm in a potato model. A bipolar electrical signal can be applied between elongated ablation electrodes in various pair combinations to achieve PFA.

[0022] Each ablation electrode can be designed with a shape based on a trade-off between total edge area, total contact area, and open space for the non-ablation electrode. The applicants recognize that a larger surface area-to-periphery ratio can effectively deliver ablation energy while reducing the opportunity for electrical arc discharge. The applicants recognize that avoiding arc discharge is desirable. Conversely, serpentine electrodes increase the mechanical flexibility of the paddle. The applicants recognize that electrode flexibility can lead to improved tissue contact and catheter life, but that the geometry of a serpentine electrode has a lower area-to-periphery ratio compared to a solid electrode.

[0023] A challenge with existing ablation catheters, particularly PFA catheters, is integrating a diagnostic electrode into the end-effector assembly so that tissue can be mapped and ablated by the same end-effector. In some embodiments, the end-effector presented herein may include, in addition to the ablation electrode, a diagnostic electrode configured to receive electrical signals from the tissue and map the tissue. Configured in this way, the end-effector is configured for both mapping and ablation.

[0024] In some embodiments, the end effector includes a pair of tissue contact electrodes for determining which portion of the end effector is in contact with the tissue.

[0025] In some embodiments, the end effector includes a reference electrode configured to measure blood voltage. An ablation electrode, diagnostic electrode, or tissue contact electrode may be used as the reference electrode when not in contact with tissue. The end effector may additionally or alternatively include one or more dedicated reference electrodes positioned on a portion of the end effector or shaft near the treatment or diagnostic electrode, such as in the proximal portion of the end effector, where contact with tissue during the procedure is less likely.

[0026] Embodiments of catheters, end effectors, and related methods and systems are described below in reference to the drawings.

[0027] Figure 1 shows an exemplary catheter-based electrophysiological mapping and ablation system 10. The system 10 may include multiple catheters that are inserted percutaneously by a physician 24 through the patient's vascular system into the lumen or vascular structure of the heart 12. Typically, a delivery sheath catheter (e.g., 8.5 French) is inserted into the left or right atrium near the desired location within the heart 12. The catheter can then be inserted into the delivery sheath catheter to reach the desired location. The multiple catheters may include a catheter dedicated to sensing intracardiac electromagnetism (IEGM) signals, a catheter dedicated to ablation, or a catheter dedicated to both sensing and ablation.

[0028] An exemplary catheter 14 is shown herein, including an end effector 100 configured to provide PFA. The end effector 100 includes an ablation electrode configured to provide PFA, and optionally, a diagnostic electrode, a tissue contact electrode, and at least one reference electrode. In some embodiments, the end effector 100 includes a diagnostic electrode configured to map abnormal electrical signals of the heart to detect atrial fibrillation, and thus the end effector 100 may be configured for both sensing and mapping. In such examples, the diagnostic electrode is on the same side of the end effector and is close to the ablation electrode. The physician 24 senses a target site within the heart 12 and brings the end effector 100 into contact with the heart wall to provide ablation treatment to the target site without the need to reposition the end effector between the mapping step and the ablation step. Electrode placement is shown in more detail in subsequent figures. The electrodes may be used for two or more purposes, as will be understood by those skilled in the art who are informed by the examples presented herein.

[0029] The magnetic-based position sensor 29 may operate in conjunction with a position pad 25, which includes a plurality of magnetic coils 32 configured to generate a magnetic field within a predetermined working range. The real-time position of the end effector 100 of the catheter 14 can be tracked based on the magnetic field generated by the position pad 25 and sensed by the magnetic-based position sensor 29 located on the catheter shaft 90. Details of magnetic-based position sensing technology are described in U.S. Patents 5,391,199, 5,443,489, 5,558,091, 6,172,499, 6,239,724, 6,332,089, 6,484,118, 6,618,612, 6,690,963, 6,788,967, and 6,892,091, which are incorporated herein by reference in their entirety. The end effector 100 may further include one or more induction coils configured to provide an electrical signal to a magnetic-based position sensing system for determining the position or orientation of the end effector. For example, the end effector 100 may include an induction loop or coil similar to that shown in Figures 5A and 5B of U.S. Patent Application Publication No. 2024 / 0215894, which is incorporated herein by reference in its entirety and is attached to the appendices herein. In some embodiments, one or more induction coils within the end effector may be used in conjunction with the position sensor 29 for determining the position or orientation of the end effector.

[0030] System 10 includes one or more electrode patches 38 positioned for skin contact on the patient 23 to establish a position reference for the position pad 25 and impedance-based tracking of the electrodes 26. For impedance-based tracking, a current is directed to the electrodes 26 and sensed at the electrode skin patches 38, thereby allowing the position of each electrode to be triangulated through the electrode patches 38. This figure shows an impedance-based tracking electrode 26 attached to a catheter shaft 90. Additionally or alternatively, the end effector 100 may include impedance-based tracking of one or more electrodes. Details of impedance-based position tracking techniques are described in U.S. Patents 7,536,218, 7,756,576, 7,848,787, and 7,869,865 and 8,456,182, which are incorporated herein by reference in their entirety.

[0031] The recorder 11 displays the electrophysical graph 21 captured by the surface ECG electrode 18. In embodiments in which the end effector 100 includes diagnostic electrodes, the recorder 11 may further display the intracardiac electrophysiogram (IEGM) derived from the electrical signals from the diagnostic electrodes on the end effector 100. The recorder 11 may include pacing capabilities for pacing the rhythm of the heart, or may be electrically connected to a standalone pacer.

[0032] System 10 includes an ablation energy generator 50 adapted to conduct ablation energy to the ablation electrode on the end effector 100. The energy generated by the ablation energy generator 50 includes pulses that induce IRE for ablation through the PFA, and may also be configured to provide radio frequency (RF) energy to warm the tissue to facilitate PFA without significant thermal ablation, or to heat the tissue for thermal ablation in addition to PFA. The ablation energy generator 50 is preferably configured to provide a biphasic bipolar pulse to induce IRE while maintaining the tissue temperature below the thermal ablation temperature. Additionally or alternatively, the ablation generator 50 may be configured to provide a single-phase IRE pulse, a single-pole IRE pulse, a thermal ablation electrical signal, or a combination thereof. For example, the ablation energy generator 50 may be configured to provide pulses similar to those described in U.S. Patent Publication Nos. 2021 / 0169550(A1), 2021 / 0177503(A1), 2021 / 0186604(A1), and 2023 / 0009191(A1), and U.S. Patent No. 11,540,877(B2), each of which is incorporated herein by reference in whole and attached to the appendices herein. U.S. Patent No. 11,540,877(B2) corresponds to U.S. Patent Publication No. 2021 / 0161592(A1), which is incorporated herein by reference in whole.

[0033] For example, as described in U.S. Patent No. 11,540,877(B2), the generator 50 may be configured to apply a bipolar pulse having an amplitude sufficient to cause IRE in the tissue contacted by the electrode, and RF energy having sufficient power to thermally ablate the tissue contacted by the electrode. In some embodiments, the sequence of bipolar pulses includes pulses having an amplitude of at least 200 V, and the duration of each bipolar pulse is less than 20 μs. Additionally or alternatively, the RF signal has a frequency of 350 to 500 kHz and an amplitude of 10 to 200 V. The end effector may further include a temperature sensor, and the electrical signal generator may be configured to apply a signal in response to the temperature measured by the temperature sensor. In some embodiments, the IRE signal may have parameters as shown in Table 1 of U.S. Patent No. 11,540,877(B2). It should be noted that the “bipolar pulse” described in U.S. Patent No. 11,540,877(B2) is referred to herein as a “two-phase pulse” relating to the shape of an electrical signal, whereas the “bipolar pulse” as described herein relates to the arrangement of electrodes receiving the pulse as defined herein.

[0034] The patient interface unit (PIU) 30 is an interface configured to establish electrical communication between the catheter, the electrophysiological equipment, the power supply, and the workstation 55 that controls the operation of the system 10. The electrophysiological equipment of the system 10 may include, for example, multiple catheters, position pads 25, surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally, and preferably, the PIU 30 includes processing power for performing real-time calculations of the catheter position and for performing ECG calculations. The PIU 30 can control the generator 50 to provide electrical energy to the ablation electrodes of the end effector 100 in accordance with the ablation protocols described above and in the incorporated references above. The PIU 30, workstation 55, and generator 50 can be collectively considered as an ablation system console having one or more output ports configured to provide ablation energy to ablation electrodes, one or more processors, and a non-transient computer-readable medium that communicates with the processors to cause the ablation system console to provide ablation energy as described above and in the following embodiments of this specification.

[0035] In some embodiments, system 10 further includes an irrigation system configured to irrigate during IRE. In some embodiments, PIU 30 is configured to control the irrigation system to provide irrigation to a catheter end effector, as described in U.S. Patent Application Publication No. 2021 / 0196372(A1), the entirety of which is incorporated herein by reference and attached to the appendices herein. The irrigation fluid can exit from the distal end of catheter 100 through a port at the distal end of the shaft or through a hole in the body of the end effector.

[0036] The workstation 55 includes memory, a processor unit having memory or storage device loaded with appropriate operating software, and user interface functions. The workstation 55 can be configured to provide multiple functions, optionally including: (1) modeling the endocardial anatomical structure in three dimensions (3D) and rendering the model or anatomical map 20 for display on a display device 27; (2) displaying on the display device 27 an activation sequence (or other data) compiled from recorded electrophoresis 21 as representative visual markers or images superimposed on the rendered anatomical map 20; (3) displaying the real-time position and orientation of one or more catheters in the cardiac chambers; and (4) displaying on the display device 27 a site of interest, such as the site where ablation energy has been applied. One commercially available product embodying the elements of system 10 is available as the CARTO® 3 system, commercially available from Biosense Webster, Inc. (31A Technology Drive, Irvine, CA 92618).

[0037] Figure 2 is a diagram of the distal portion of a catheter 14 including an exemplary end effector 100. Figure 2 shows the first side 101a of the end effector 100. The end effector has a planar body 140 with a second side 101b (Figures 9A-9D, 12A-14) opposite to the first side. The second side 101b has electrodes, which are not required but preferably arranged similarly to those on the first side 101a. When the end effector 100 is configured with similar electrode configurations on both sides 101a, 101b, either side can be positioned against tissue during treatment. When one side of the end effector 100 is in contact with tissue, the corresponding electrode on the opposite side is in contact with body fluid (e.g., blood) and can function as a reference electrode for the electrode in contact with the tissue.

[0038] The end effector 100 includes an ablation electrode having longitudinally elongated segments 111a, 111b, 112a, and 112b, respectively, that extend along the longitudinal axis AA defined by the catheter shaft 90. The longitudinally elongated segments 111a and 111b on the left side of the longitudinal axis AA form the first ablation electrode 111 (Figure 8). The longitudinally elongated segments 112a and 112b on the right side of the longitudinal axis AA form the second ablation electrode 112 (Figure 8). The ablation electrode has a length L2 which is at least half the total length L1 of the end effector 100 when measured from the distal end 106 of the end effector to the distal end of the shaft 90 of the medical probe 14. The ablation electrodes 111 and 112 extend to approximately the distal end 106 of the end effector 100. The length L2 of the ablation electrode defines the distal portion of the end effector 100. The end effector 100 has a width W1 measured from its leftmost and rightmost ends. As shown in the figure, the leftmost and rightmost ends of the end effector 100 define the parallel side edges of the end effector 100. The planar body 140 is preferably aligned with the longitudinal axis AA when in an unconstrained configuration as shown in Figure 2.

[0039] The ablation electrodes 111 and 112 are configured to deliver ablation energy to tissue, as will be described in more detail elsewhere in this specification. The second side 101b of the planar body 140 of the end effector 100 preferably includes an ablation electrode having longitudinally elongated segments on the opposite side of the illustrated longitudinally elongated segments 111a, 111b, 112a, and 112b electrodes with respect to the plane defined by the planar body 140. In some embodiments, the ablation electrodes 111 and 112 are coplanar with the planar body 140 and provide the end effector with a first plane corresponding to the first side 101a of the planar body and a second plane corresponding to the end effector with respect to the second side 101b of the planar body.

[0040] In some embodiments, the ablation electrode on the second side 101b can function as the respective reference electrode for each opposing ablation electrode on the first side 101a when the first side 101a is in contact with tissue, and vice versa. Additionally or alternatively, the ablation electrodes on both sides 101a, 101b can be paired to provide a bipolar PFA electrical signal between the paired ablation electrodes. Additionally or alternatively, the ablation electrodes on the same side can be paired to provide a bipolar PFA electrical signal between the paired ablation electrodes. The bipolar PFA electrical signal may be monophasic or biphasic.

[0041] The illustrated end effector 100 includes optional diagnostic electrodes 113, 114 on the first side 101a, electrically isolated from the ablation electrode segments 111a, 111b, 112a, 112b. The diagnostic electrodes 113, 114 are configured to receive electrical signals from the tissue in order to map cardiac tissue and detect arrhythmias. As shown, the diagnostic electrodes 113, 114 are arranged in pairs such that the first diagnostic electrode 113 is on the left side of the longitudinal axis AA and the second diagnostic electrode 114 is on the right side of the longitudinal axis AA. The diagnostic electrodes 113, 114 are arranged diametrically along axis DA, which is perpendicular to the longitudinal axis AA with respect to each other. The second side 101b of the planar body 140 of the end effector 100 preferably includes a second pair of diagnostic electrodes opposite the first pair of diagnostic electrodes with respect to the plane defined by the planar body 140.

[0042] The illustrated end effector 100 includes arbitrary tissue contact quality electrodes 115, 116 arranged in closely spaced pairs such that the impedance measured across each pair of tissue contact quality electrodes indicates that both electrodes of the pair are in contact with the tissue. As shown, the first side 101a includes a distal pair of tissue contact quality electrodes 115 positioned near the distal end 106 of the end effector 100, and a central pair of tissue contact quality electrodes 116 positioned approximately in the middle of the length L2 of the distal portion of the end effector 100. The pairs of tissue contact quality electrodes 115, 116 are spaced apart along the longitudinal axis AA. The planar body 140 of the end effector includes a central portion 104 that extends centrally along the longitudinal axis AA and along the total length L1 lacking the ablation electrodes. As shown, the tissue contact quality electrodes 115, 116 are positioned in this central portion 104. The second side 101b of the planar body 140 of the end effector 100 preferably includes a corresponding pair of tissue contact quality electrodes on the opposite side of the pair of tissue contact quality electrodes 115, 116 on the first side 101a with respect to the plane defined by the planar body 140.

[0043] The illustrated end effector 100 includes an optional reference electrode 117 positioned on the first side 101a of the planar body 140. Additionally or alternatively, the end effector 100 may include a reference electrode similarly positioned on the second side 101b of the planar body 140. The reference electrode 117 may be used for ECG acquisition or as a reference in either a unipolar or bipolar (split or proximity pair) configuration. Its number can be as few as four per side, but can be more as needed (to accommodate trace limitations). Signals from the reference electrode 117 can also be used for contact information to determine which portion of the paddle is in contact with or near tissue. The end effector 100 includes a proximal portion defined by a proximal length L3 that lacks an ablation electrode. The reference electrode 117 may be positioned in this proximal portion. As discussed herein, an ablation electrode, diagnostic electrode, or tissue contact electrode may be used as a reference electrode for the corresponding electrode on the opposite side that is in contact with tissue. Each of these electrodes is positioned in the distal portion of the end effector 100, defined by the length L2 of the ablation electrode, so that it can be positioned in contact with tissue if desired by the physician 24 (Figure 1). Preferably, the reference electrode 117 is positioned so that the physician 24 cannot, or at least very unlikely, position the reference electrode 117 in contact with tissue, but nevertheless, it is positioned relatively close to the electrode configured to contact tissue. For example, the end effector 100 may be configured to bend so that the majority of the proximal portion does not contact tissue while the distal portion of the first side 101a is in contact with tissue. By being positioned in the proximal portion, the reference electrode 117 cannot, or is unlikely to, contact tissue during the procedure. In other words, the end effector is configured to bend so that the majority of the first side 101a of the distal portion conforms to a plane, while the reference electrode is separated from the plane. In such embodiments, the illustrated reference electrode 117 is a dedicated reference electrode rather than a multipurpose electrode.

[0044] In some embodiments, at least the ablation electrode, diagnostic electrode, and tissue contact electrode are coplanar with the planar body, providing a first plane to the end effector 100 corresponding to the first side 101a of the planar body 140 and a second plane to the end effector 100 corresponding to the second side 101b of the planar body. Any combination of the ablation electrodes 111, 112 and the other electrodes 113, 114, 115, 116, 117 may include an exposed conductive layer in a flexible printed circuit board, or it may include silver epoxy or conductive ink.

[0045] The illustrated planar body 140 includes openings 102, 105 between the first side 101a and the second side 101b. The openings 102, 105 may be sized, shaped, or otherwise configured to allow the end effector to bend through the sheath catheter. The opening configuration may be determined by the size of the sheath catheter through which the end effector is delivered. The openings 102, 105 may be sized, molded, or otherwise configured to fold or expand when the end effector is pressed against a non-planar tissue surface to provide conformal contact with the non-planar tissue surface. The applicants recognize that consistent contact of the ablation electrode to non-planar tissue may produce improved damage compared to less conformal electrode contact. In some embodiments, the distal end may not be completely closed to allow for greater flexibility and a larger area. In some embodiments, the EM loop extends through a paddle spine between the openings. The outer opening 102 is located between the elongated ablation electrode segments 111a, 111b, 112a, and 112b of the respective ablation electrodes 111 and 112. The inner opening 105 is located between the inner elongated ablation electrode segments 111b and 112b and the central portion 104.

[0046] Figure 3 is an enlarged view of a portion of an exemplary end effector 100 shown in Figure 2. The planar body 140 includes a frame 150 surrounded by a flexible electrically insulating seal 142. The insulating seal may consist mainly of polymer material or may include higher insulating components, as will be described in more detail in relation to Figures 9A to 9D. The frame 150 is elastic and provides structural support to the end effector 100, allowing the end effector to contract into a delivery configuration for delivery through the sheath, then self-expand into an unconstrained planar configuration as shown, bending to allow the distal portion to conform to a planar or substantially planar surface such as tissue, and folding in response to retraction into the sheath. The frame 150 can be formed from superelastic materials or shape memory alloys such as nickel-titanium, also known as nitinol, cobalt-chromium, stainless steel, or other alloys exhibiting pseudoelastic or superelastic properties.

[0047] The illustrated portion of the planar body 140 is divided into three segments: an outer segment containing an outer elongated ablation electrode segment 111a, an inner segment containing an inner elongated ablation electrode segment 111b, and a central portion 104. The planar body 140 includes a second outer segment and a second inner segment to the right of the planar body, as shown in Figure 2 but not in Figure 3, resulting in a total of five segments for the planar body 140. The outer segment has a width W4, the inner segment has a width W3, and the central portion 104 has a width W2. In the illustrated example, the body segment widths W2, W3, and W4 are approximately equal to each other. Each elongated ablation electrode segment 111a, 111b has a width W5 that is more than half, or about 80%, of the width of the outer body segment width W4 and the inner body segment width W3. The ablation electrode segment width W5 is about 10% of the total width W1 of the end effector 100.

[0048] The elongated ablation electrode segments 111a and 111b are positioned to the left or right of each other. Each of the elongated ablation electrode segments 111a and 111b extends distally to approximately the distal edge of the planar body 140. Due to the curvature of the distal edge, the length L2 of the distal portion of the inner ablation electrode segment 111b is defined, while the length L5 of the outer ablation electrode segment 111a is shorter than the length L2 of the inner ablation electrode segment 111b.

[0049] The illustrated diagnostic electrode 113 is positioned entirely on the outer segment of the planar body 140 and within the width W5 and length L5 of the outward longitudinally extending ablation electrode segment 111a. The diagnostic electrode 113 has a width W7 of less than half, preferably about one-third, of the width W5 of the outward longitudinally extending ablation electrode segment 111a. The diagnostic electrode 113 has a length L4 of less than half, less than about one-fifth, or less than one-tenth of the length L5 of the outward longitudinally extending ablation electrode segment 111a.

[0050] Each elongated ablation electrode segment 111a, 111b has a meandering shape. The meandering shape of the ablation electrode segment 111a extending in the outer longitudinal direction bends around three of the four sides of the diagnostic electrode 113. As shown in the figure, the meandering shape has a path width W6 which is approximately equal to the width W7 of the diagnostic electrode W7 and about one-third of the width W5 of the ablation electrode segment 111a extending in the outer longitudinal direction.

[0051] The end effector 100 further includes electrical traces 118, 119 having insulated, meandering conductive portions. The illustrated electrical traces 118, 119 extend longitudinally and form meandering paths within the central portion 104. The illustrated electrical traces 118, 119 form electrical connections to the central pair of tissue contact quality electrodes 116 and the distal pair of tissue contact quality electrodes 115.

[0052] Figure 4 is a diagram of a first alternative electrode configuration of the exemplary end effector 100, including one exemplary configuration of ablation electrodes 111 and diagnostic electrodes 113. Similar to Figures 2 and 3, the ablation electrode 111 includes a meandering longitudinally extending segment having a total width W5 and a path width W6. While the configurations in Figures 2 and 3 include only one diagnostic electrode 113 per ablation electrode 111, the example in Figure 4 includes six diagnostic electrodes 113 per ablation electrode 111. The end effector 100 may include one, two, three, four, five, or six diagnostic electrodes 113 per ablation electrode 111. Each diagnostic electrode is similarly sized to have a width W7 that is approximately 1.5 times the path width W6 of the ablation electrode 111 and approximately half the total width W5 of the elongated segment of the ablation electrode 111. The diagnostic electrode 113 is surrounded on two or three sides by each of the elongated segments of the ablation electrode 111.

[0053] Figure 5 shows a second alternative electrode configuration of an exemplary end effector, comprising an ablation electrode 111 having elongated segments, each segmented into small parallel stripes, and a diagnostic electrode 113 positioned along the elongated ablation electrode segments. Each elongated segment has multiple conductive stripes extending parallel to each other to form the overall shape of each elongated segment, similar to that shown in Figure 4. Other ablation electrode shapes shown herein, and their alternatives as understood by those skilled in the art, can also be divided into multiple conductive stripes extending parallel to each other, similar to that shown in Figure 5. This configuration increases the total edge length of the ablation electrode, providing a different electric field profile in the tissue compared to similarly shaped solid ablation electrodes (e.g., as shown in Figure 4).

[0054] Figure 6 shows a third exemplary electrode configuration of an exemplary end effector, including a rectangular elongated segment of the ablation electrode 111 without a diagnostic electrode 113. The total width W5 of the electrode segment is utilized for the ablation electrode 111 to maximize its surface area. The diagnostic electrode may be located elsewhere on the planar body, for example, in the central portion 104.

[0055] Figure 7 shows a fourth exemplary electrode configuration of an exemplary end effector, which includes a rectangular elongated segment of the ablation electrode 111 interrupted by the diagnostic electrode 113. Compared to the continuous rectangular electrode segment shown in Figure 6, the segmented elongated ablation electrode segment can have greater flexibility for bending the planar body 140 away from the longitudinal axis AA, at the expense of the total ablation electrode area.

[0056] Figure 8 is a diagram of an exemplary electrode configuration on one side of an exemplary end effector, including elongated ablation electrodes 111, 112 in two ablation electrode regions 121, 122, diagnostic electrodes 113, 114 positioned within the two ablation electrode regions 121, 122, tissue contact electrodes 115, 116 positioned between the two ablation electrode regions 121, 122, and a reference electrode 117 positioned within the proximal region on the illustrated side of the end effector. In some embodiments, the total area of ​​each ablation electrode 111, 112 within each electrode region 121, 122 is approximately 7.5 mm². 2In Figure 8, it can be seen that there are two individual ablation electrodes 111a and 111b on the left side and two individual ablation electrodes 112a and 112b on the right side. The left electrodes 111a and 111b are connected to a pulse field generator, which can deliver a biphasic pulse field between electrodes 111a and 111b. The right electrodes 112a and 112b are connected to a pulse field generator, which can deliver a biphasic pulse field between electrodes 112a and 112b. Alternatively, each of the left electrodes 111a and 111b can be connected to a generator together with each of the right electrodes 112a and 112b, which can deliver a bipolar pulse between the left and right electrodes. For example, a bipolar electrode pair may be formed by one or more left electrodes 111a and 111b and one or more right electrodes 112a and 112b.

[0057] The center line CC, shown in Figure 8, indicates the line of symmetry of the electrode configuration or the planar body. As shown, the electrode configuration is symmetrical with respect to the center line CC. Preferably, at least the ablation electrodes 111 and 112 are symmetrical with respect to the center line CC. The planar body may have a shape symmetrical with respect to the center line CC, as shown. In an alternative embodiment, the planar body may not be symmetrical with respect to the center line CC. As shown, the center line CC has the same extent as the longitudinal axis AA. In an alternative embodiment, the center line CC may not have the same extent as the longitudinal axis AA.

[0058] The illustrated planar body has a left half to the left of the centerline CC and a right half to the right of the centerline CC. The first ablation electrode 111 defines a first electrode region 121 that is entirely on the left half of the planar body 140. The second ablation electrode 112 defines a second electrode region 122 that is entirely on the right half of the planar body 140. The tissue contact electrodes 115 and 116 are arranged in pairs, each positioned across the centerline CC on the illustrated side of the planar body 140. The distal pair of tissue contact electrodes 115 is close to the distal end 106 of the planar body 140. The central pair of tissue contact electrodes 116 is proximal to the distal pair 115 and crosses the centerline CC. The reference electrode 117 is positioned on the illustrated side of the planar body 140, crossing the centerline CC.

[0059] Figures 9A to 9D illustrate alternative configurations of insulating materials in the cross-section of the end effector. Opposite the first side 101a, the second side 101b of the planar body 140 is shown. Ablation electrodes 131 and 132 are shown on the second side 101b, opposite to the ablation electrodes 111 and 112 on the first side. The opposing ablation electrodes 131 and 132 overlap with the ablation electrodes 111 and 112 on the first side 101a, preferably overlapping with a large portion of the ablation electrodes 111 and 112 on the first side 101a, and may be symmetrical with respect to the ablation electrodes 111 and 112 on the first side 101a with respect to the plane defined by the planar body 140. The cross-section of the planar body 140 is simplified for illustrative purposes, omitting the frame 150, electrical traces, and other such features. The ablation electrodes 111, 112, 131, and 132 are shown protruding from the planar body 140, but alternatively, they may be recessed within the planar body 140 to provide smooth planes on each of their respective sides 101a and 101b. The ablation electrodes 111, 112, 131, and 132 may have approximately equal surface areas to each other. Each segment 111a, 111b, 112a, 112b, 131a, 131b, 132a, and 132b of the ablation electrodes are shown to be continuous across their width. Alternatively, some or all of the segments may include parallel stripes similar to those shown in Figure 5, resulting in a segmented cross-sectional profile.

[0060] The various configurations shown in Figures 9A to 9D provide different levels of electrical insulation between the electrodes on both sides of the planar body. The electrical insulation can be adjusted to direct the electric field lines between the bipolar pairs of ablation electrodes on both sides of the planar body 140 during PFA application, thereby directing the electroporation of cells within the target tissue.

[0061] Figure 9A shows the end effector configured with openings within it, as shown in Figure 8. Figure 9B includes a polymer body region extending across the width of the end effector. Essentially, some or all of the openings 102, 105 (and other unreferenced openings) of the exemplary end effector 100 shown in Figures 2 and 3 can include their respective thin polymer-filled regions lacking a framework or any electrical circuits. When configured in this way, the planar body 140 can provide additional electrical insulation between the electrodes on both sides of the planar body 140 (compared to the openings 102, 105) while maintaining sufficient flexibility for operations to be positioned against the tissue and transported through the sheath. Figure 9C includes a planar high-dielectric layer 144 located between each side and extending across the width of the end effector. The dielectric layer 144 overlaps and is parallel to each of the ablation electrodes 111, 112, 113, and 114. The planar high dielectric layer 144 may contain a ceramic-doped polymer, which still provides sufficient flexibility while offering additional electrical insulation between the electrodes on both sides of the planar body compared to the polymer alone. As shown, the planar high dielectric layer 144 extends over most of the total width W1 of the planar body 140. The planar body 140 includes the planar high dielectric layer 140, and includes longitudinally elongated regions (e.g., corresponding to openings 102, 105 in Figures 2 and 3) that lack a framework and electrical circuits. Figure 9D includes a high dielectric tile 145 located between each side 101a, 101b and configured to overlap to fold the end effector 100 into the delivery sheath. The high dielectric tile 145 extends longitudinally through each segment of the body and may include ceramic plates that overlap between segments such that the overlaps correspond to openings 102, 105 shown in Figures 2 and 3. The highly dielectric tiles or longitudinally extending ceramic plates may be angled with respect to the plane defined by the planar body 140 such that when the end effector retracts into the sheath, the tiles / plates 145 overlap each other at their longitudinal sides.

[0062] Figure 10 shows an end effector configured such that the ablation electrodes provide a pulse of 1,200 V between the ablation electrode regions. In some embodiments, the end effector 100 is configured to provide PFA electrical pulses having voltages of approximately 600 V and approximately 1,200 V between pairs of ablation electrodes 111, 112, 131, and 132. As shown in Figure 10, the end effector 100 is configured to provide an electrical pulse of amplitude 1,200 V between bipolar pairs including the ablation electrode on the left side of the planar body in contact with the tissue, i.e., electrode 111, and the electrode on the right side of the planar body not in contact with the tissue, i.e., electrode 132. Similarly, electrodes 112 and 131 are paired. The paired electrodes are on either side of the planar body 140 and do not overlap.

[0063] In some embodiments, cardiac electrical signals may be measured from one or more diagnostic electrodes positioned on the side of a planar body that contacts tissue. In some embodiments, tissue contact may be measured from a pair of tissue contact electrodes positioned on the side of the planar body that contacts tissue. In some embodiments, a reference electrical signal may be measured from a reference electrode positioned on the tissue-contacting side of the planar body, the reference electrode itself not in contact with tissue.

[0064] Figure 11 shows an end effector 100 applying the procedure shown in Figure 10 to a potato model 160. The PFA electrical signal applied to the ablation electrodes results in damage 161 having a depth D1 of approximately 7.5 millimeters (mm). To create the damage, a first bipolar PFA electrical signal is applied to the first and second ablation electrodes, the first ablation electrode positioned on the first side of the planar body of the planar end effector, and the second ablation electrode positioned on the second side of the planar body, not overlapping with the first ablation electrode (i.e., ablation electrode pair 111, 132). The first bipolar PFA electrical signal consists of 60 pulses having a magnitude of approximately 1,200 V and a total duration of approximately 4 seconds. A second bipolar PFA electrical signal is applied between the third and fourth ablation electrodes, the third ablation electrode being positioned on the first side of the planar body of the planar end effector and overlapping with the second ablation electrode, and the fourth ablation electrode being positioned on the second side of the planar body and overlapping with the second ablation electrode, i.e., ablation electrode pair 112, 131. The second bipolar PFA electrical signal consists of 60 pulses having a magnitude of approximately 1,200 V and a total duration of approximately 4 seconds. The bipolar pulses may include an inter-pulse delay of approximately 2 microseconds.

[0065] Figures 12A, 12B, 12C, 13, 14, 15A, and 15B show ablation electrode pair configurations for the application of bipolar PFA electrical pulses having voltages of approximately 600V and approximately 1,200V in an embodiment in which the end effector 100 includes a total of four ablation electrodes 111, 112, 131, and 132. As will be described in more detail in relation to Figure 10, the end effector 100 preferably includes a total of 2 to 8 ablation electrodes. The pattern of ablation electrode pairs can be adapted based on the total number of ablation electrodes in the end effector 100, as will be understood by those skilled in the art who are informed by the disclosure herein, and as will be discussed in more detail in relation to Figure 10.

[0066] Figures 12A and 12B show crossed body pairs for ablation electrodes as described in relation to Figures 10 and 11. The pair of ablation electrodes are symmetrical with respect to the center line CC and are located on both sides of the planar body 140. A voltage is applied across the electrode pairs of electrode regions, for each pair, the ablation electrode in the first electrode region is in contact with the tissue, and the other electrode region is on the opposite side of the end effector and crosses the center line CC from the first electrode region. Figures 12A and 12B show two different pairs of electrode regions. Figure 12A shows elongated segments 111a, 111b of the ablation electrode 111 which have a positive charge, while elongated segments 132a, 132b of the ablation electrode 132 have a negative charge. This shows a positive voltage pulse configured to induce electroporation in the tissue in contact with either side 101a, 101b of the planar body 140. A biphasic pulse may be applied, in which case the polarity switches or alternates between a positive charge on the ablation electrode 132 that is not in contact with the tissue and a negative charge on the ablation electrode 111 that is in contact with the tissue, as shown in Figure 12A. A series of bipolar pulses (which may include biphasic, monophasic, or a combination thereof) can be applied between the bipolar ablation electrode pair 111, 132 as shown in Figure 12A, and then a series of bipolar pulses can be applied between the bipolar ablation electrode pair 112, 131 as shown in Figure 12B.

[0067] Figure 12C shows another configuration in which ablation electrodes 131a and 131b are thought to be in contact with tissue. In this example, ablation electrodes 131a and 131b are no longer connected to each other but are connected separately to the generator, and as a result a biphasic pulsed field can be provided between these two tissues in contact with the ablation electrodes in a bipolar configuration to allow electron flow between 131a and 131b. Similarly, ablation electrodes 131c and 131d (in tissue contact) are no longer connected to each other but are connected separately to the generator, and as a result a biphasic pulsed field can be provided in a bipolar manner between these two tissue-contact ablation electrodes to allow electron flow between them.

[0068] Figure 13 shows an ablation electrode pair configuration in which the pair of ablation electrodes are symmetrical with respect to the center line CC and located on the same side of the planar body 140. As shown, a voltage is applied across electrodes 111, 112 on one side 101a of the planar body 140 that is in contact with the tissue. Electrodes 131, 132 that are not in contact with the tissue can function as reference electrodes. A biphasic pulse may be applied, in which case the polarity switches or alternates, as shown in Figure 13, with a positive charge on the right ablation electrode 112 and a negative charge on the left ablation electrode 111. A series of bipolar pulses can be applied between the bipolar ablation electrode pair 111, 112.

[0069] Figure 14 shows an ablation electrode pair configuration where the pair of ablation electrodes overlap and are located on both sides of a planar body. The voltage is applied across the ablation electrodes 111, 112 that are in contact with the tissue to the ablation electrodes 131, 132 on the opposite side of the planar body 140 that are not in contact with the tissue. A biphasic pulse may be applied, in which case the polarity switches or alternates, as shown in Figure 14, with positive charges on the ablation electrodes 131, 132 that are not in contact with the tissue and negative charges on the ablation electrodes 111, 112 that are in contact with the tissue. A series of bipolar pulses may be applied between the bipolar ablation electrode pair. As shown, both electrodes 111, 112 that are in contact with the tissue are activated simultaneously. Alternatively, a series of bipolar pulses may be applied to the first ablation electrode pair while the second pair is de-energized, and then a series of bipolar pulses may be applied to the second ablation electrode pair while the first pair is de-energized.

[0070] Figures 15A and 15B illustrate the voltage applied across an electrode pair, where the pair of electrodes are positioned across the central axis from each other. The pair is asymmetrical with respect to the centerline, with one electrode (or set of electrodes) of the pair closer to the centerline than the other. In this configuration, the electrode segments on both sides of the end effector body can act as a unit and be electrically coupled within the catheter. For example, electrodes 111a and 131a can form a bipolar pair with electrodes 112b and 132b, as shown in Figure 15A. Similarly, electrodes 111b and 131b can form a bipolar pair with electrodes 112a and 132a, as shown in Figure 15B. Alternatively, only the electrodes on the side of the planar body in contact with the tissue may be activated. For example, ablation electrodes 111a and 112b may form a bipolar pair in Figure 15A, while the opposing ablation electrodes 131a and 132b are off. Similarly, in Figure 15B, the ablation electrodes 111b and 112a may form the bipolar pair shown in Figure 15A, while the opposing ablation electrodes 131b and 132a are off. A series of bipolar pulses (which may include biphasic, monophasic, or a combination thereof) may be applied between the bipolar ablation electrode pair and switched back and forth between the bipolar configurations of Figures 15A and 15B, as shown in Figure 15A and then in Figure 15B.

[0071] Figure 16 is a diagram of an exemplary electrode configuration on one side of an exemplary end effector, which includes elongated ablation electrodes 171, 172, 173, and 174 in four ablation electrode regions 181, 182, 183, and 184, diagnostic electrodes 113, and 114 positioned in at least two of the ablation electrode regions 181 and 182, tissue contact electrodes 115, and 116 positioned along the center line CC between the ablation electrode regions, and a reference electrode 117 positioned in the proximal region on the illustrated side of the end effector 100. Embodiments of the end effector 100 described herein include exactly four ablation electrodes 111, 112, 131, and 132, while the embodiment shown in Figure 15 includes up to eight ablation electrodes, including those indicated as 171, 172, 173, and 174, and corresponding overlapping ablation electrodes on the opposite side of a planar body not shown.

[0072] The end effector 100 preferably includes a total of 2 to 8 ablation electrodes. The end effector 100 preferably includes exactly 2, 3, or 4 ablation electrodes on each side of the planar body 140. Each ablation electrode preferably overlaps with the corresponding ablation electrode on the opposite side of the planar body such that the ablation electrode is symmetrical with respect to the plane defined by the planar body 140. Fewer ablation electrodes can be achieved by electrically connecting combinations of ablation electrodes within the end effector 100 or other locations within the catheter 14. Increasing the number of ablation electrodes can be achieved by dividing the ablation electrodes into two parts configured to be electrically insulated from each other within the catheter 14 and to be operated independently by the generator 50. Figure 15 shows one embodiment in which the ablation electrode 111 on the left side of the centerline CC as shown in Figure 8 is segmented into two electrodes, namely the upper left ablation electrode 171 and the lower left ablation electrode 173. Similarly, as shown in Figure 8, the ablation electrode 112 to the right of the center line CC is segmented into two electrodes, namely the upper right ablation electrode 172 and the lower right ablation electrode 174. Preferably, all ablation electrodes 171, 172, 173, and 174 have approximately the same surface area as each other.

[0073] Figure 17 shows an exemplary electrode configuration of an exemplary end effector including an elongated, serpentine ablation electrode. The elongated segment is serpentine, similar to that shown in Figure 3. In one embodiment, the trace width W6 is approximately 0.28 mm, the electrode segment width W5 is approximately 1 mm, the ablation electrode surface area is approximately 10.1 square mm, the perimeter is approximately 67.7 mm, and the perimeter-to-area ratio is approximately 7:1.

[0074] Figure 18 shows an exemplary electrode configuration of an exemplary end effector, which includes a rectangular elongated ablation electrode. The elongated segment is solid, as shown in Figure 6, meaning that the trace width is equal to the total width. In one embodiment, the electrode segment width W5 is approximately 1 mm, the ablation electrode surface area is approximately 16.8 square mm, the perimeter is approximately 37.4 mm, and the perimeter-to-area ratio is approximately 2:1.

[0075] Figure 19 shows an exemplary electrode configuration of an exemplary end effector including a large-area ablation electrode. In one embodiment, the electrode segment width W5 is approximately 3.5 mm, the ablation electrode surface area is approximately 28.8 square mm, the perimeter is approximately 24.8 mm, and the perimeter-to-area ratio is approximately 1:1.

[0076] Figure 20 shows an exemplary electrode configuration of an exemplary end effector, in which the ablation electrode wraps around the spine or insulating material of the catheter body.

[0077] Figure 21 shows an exemplary electrode configuration of an exemplary end effector, in which the ablation electrode partially wraps around the spine or insulating material of the catheter body.

[0078] Each electrode in Figures 20 and 21 can be operated independently to form a bipolar pair that is symmetrical or asymmetrical with respect to the center line CC.

[0079] Ablation electrodes can be paired in various combinations to provide a bipolar PFA electrical signal between the paired electrodes. Table 1 includes an overview of selected exemplary ablation electrode pairs based on the examples shown herein. As will be understood by those skilled in the art who are informed by the disclosure herein, pairs can be operated simultaneously or sequentially in various combinations to achieve PFA of the target tissue.

[0080] [Table 1]

[0081] In another alternative embodiment (not shown), segments 111a and 111b of the left ablation electrode 111 shown in Figure 8 may be electrically insulated from each other to form separate ablation electrodes. In an embodiment where all elongated ablation electrode segments form independent electrodes, the end effector 100 includes a total of eight elongated ablation electrodes. The exemplary ablation electrode configurations illustrated and described herein are non-limiting, and numerous other ablation electrode configurations are possible. In each ablation electrode configuration, the ablation electrodes may be paired according to the same concepts outlined in Table 1.

[0082] The following clauses enumerate non-limiting embodiments of this disclosure.

[0083] Clause 1. An end effector for a medical probe, the end effector comprising: a planar body extending along a longitudinal axis, having a first side and a second side opposite to the first side; and a plurality of ablation electrodes, including a first ablation electrode and a second ablation electrode located on the first side of the planar body, wherein the end effector is configured to provide a bipolar pulsed-field ablation electrical signal between the first ablation electrode and the second ablation electrode, each having a length of at least half the total length of the end effector when measured from the distal end of the end effector to the distal end of the shaft of the medical probe, and the respective lengths of the first ablation electrode and the second ablation electrode define the distal portion of the end effector.

[0084] Clause 2. The end effector according to Clause 1, further comprising at least one diagnostic electrode located on at least one of the first or second sides of a planar body, wherein the at least one diagnostic electrode is electrically isolated from the plurality of ablation electrodes and configured to receive electrical signals from tissue.

[0085] Clause 3. The end effector according to Clause 2, wherein at least one diagnostic electrode comprises a plurality of pairs of diagnostic electrodes, each pair arranged diametrically along axes perpendicular to each other's longitudinal axes on their respective first and second sides.

[0086] Clause 4. The end effector according to any one of Clauses 1 to 3, further comprising a pair of tissue contact electrodes positioned on the first side of a planar body.

[0087] Clause 5. The end effector according to any one of Clauses 1 to 4, further comprising a plurality of pairs of tissue contact electrodes spaced apart along the longitudinal axis, wherein each pair of tissue contact electrodes is located in close proximity to the distal portion of the end effector and on at least one of the first or second sides.

[0088] Clause 6. The end effector according to any one of Clauses 1 to 4, comprising: a plurality of first ablation electrodes, each of which is a plurality of first ablation electrodes, each of which is connected to three other ablation electrodes to form one or more combined first ablation electrodes having a larger electrode area than any individual first ablation electrode; and a plurality of second ablation electrodes, each of which is a plurality of second ablation electrodes, each of which is connected to any of three other second ablation electrodes to form a combined second ablation electrode having a larger electrode area than any individual second ablation electrode.

[0089] Clause 7. An end effector according to any one of Clauses 1 to 6, comprising a proximal portion proximal to a distal portion and lacking any ablation electrodes.

[0090] Clause 8. The end effector according to Clause 7, wherein any two of the individual first ablation electrodes are configured to be electrically connected to a biphasic pulsed field generator, and any two of the individual second ablation electrodes may be electrically connected to a biphasic pulsed field generator, and the end effector further comprises a reference electrode located on the first side and proximal portion of the planar body.

[0091] Clause 9. The end effector according to Clause 8, wherein the end effector is configured such that the majority of the first side of the distal portion conforms to a plane, while the reference electrode is bent so as to be separated from the plane.

[0092] Clause 10. An end effector as described in any one of Clauses 1 to 9, wherein the first ablation electrode and the second ablation electrode each extend to the substantially distal end of the end effector.

[0093] Clause 11. The end effector according to any one of Clauses 1 to 10, wherein the planar body comprises a central portion extending centrally along the longitudinal axis and along the entire length of the end effector, measured from the distal end of the end effector to the distal end of the shaft of the medical probe, the central portion lacking an ablation electrode.

[0094] Clause 12. The end effector according to any one of Clauses 1 to 11, wherein the first ablation electrode comprises a plurality of longitudinally elongated segments arranged to the left or right of each other.

[0095] Clause 13. The end effector according to Clause 12, wherein each of the multiple longitudinally extending segments defines a width, and the diagnostic electrode is fully positioned within the width of each longitudinally extending segment of the first ablation electrode.

[0096] Clause 14. The end effector described in Clause 13, wherein the diagnostic electrode has a width of less than half the width of each segment extending in the longitudinal direction.

[0097] Clause 15. The width of the diagnostic electrode is approximately one-third of the width of the segment extending in the longitudinal direction, as described in Clause 14.

[0098] Clause 16. The end effector according to any one of Clauses 12 to 15, wherein the diagnostic electrode is fully positioned within the length of each longitudinally extending segment of the first ablation electrode.

[0099] Clause 17. The diagnostic electrode is an end effector as described in Clause 16, which includes a length of less than half the length of each segment extending in the longitudinal direction.

[0100] Clause 18. The diagnostic electrode is an end effector as described in Clause 17, which includes a length of less than one-fifth of the length of each segment extending in the longitudinal direction.

[0101] Clause 19. The diagnostic electrode is an end effector as described in Clause 18, which includes a length of less than one-tenth of the length of each segment extending in the longitudinal direction.

[0102] Clause 20. Each of the multiple ablation electrodes is an end effector as described in any one of Clauses 1 to 19, having a serpentine shape.

[0103] Clause 21. The meandering shape of the first ablation electrode is bent around at least three of the four sides of the diagnostic electrode, as described in Clause 20.

[0104] Clause 22. An end effector according to any one of Clauses 1 to 21, wherein each of the elongated segments comprises a plurality of conductive stripes extending parallel to each other and forming the overall shape of each elongated segment of the plurality of elongated segments.

[0105] Clause 23. An end effector according to any one of Clauses 1 to 22, further comprising an electrical trace having an insulated, meandering conductive portion.

[0106] Clause 24. The total surface area of ​​the first ablation electrode shall be approximately 7.5 mm². 2 The end effector described in any one of the clauses 1 to 23.

[0107] Clause 25. An end effector according to any one of Clauses 1 to 24, wherein each of the multiple ablation electrodes is coplanar with the planar body, provides the end effector with a first plane corresponding to a first side of the planar body, and provides the end effector with a second plane corresponding to a second side of the planar body.

[0108] Clause 26. An end effector according to any one of Clauses 1 to 25, further comprising an induction loop navigation sensor located within a planar body.

[0109] Clause 27. Multiple ablation electrodes comprising silver epoxy, as described in any one of Clauses 1 to 26.

[0110] Clause 28. Multiple ablation electrodes, including conductive ink, as described in any one of Clauses 1 to 27.

[0111] Clause 29. An end effector as described in any one of Clauses 1 to 28, wherein the planar body is symmetrical with respect to a center line that bisects the planar body along its longitudinal axis.

[0112] Clause. The end effector according to Clause 29, wherein the planar body has a left half and a right half when viewed from a first side, the left half being to the left of the center line and the right half being to the right of the center line, and the first ablation electrode defines a first electrode region that is entirely located in the left half.

[0113] Clause 31. The end effector according to Clause 30, further comprising a pair of tissue contact electrodes positioned on the first side of the planar body across the centerline.

[0114] Clause 32. The end effector according to Clause 30 or 31, wherein a pair of tissue contact electrodes are located close to the distal end of the end effector.

[0115] Clause 33. The end effector according to Clause 32, further comprising a second pair of tissue contact electrodes positioned proximal to the pair of tissue contact electrodes and across the centerline to the first side.

[0116] Clause 34. An end effector according to any one of Clauses 30 to 33, further comprising a reference electrode positioned on the first side of the planar body across the centerline.

[0117] Clause 35. The end effector according to any one of Clauses 30 to 34, wherein the plurality of ablation electrodes further comprises a third ablation electrode and a fourth ablation electrode, and the end effector is configured to provide a bipolar pulsed-field ablation electrical signal between the third ablation electrode and the fourth ablation electrode.

[0118] Clause 36. The end effector according to Clause 35, wherein the first ablation electrode, the second ablation electrode, the third ablation electrode, and the fourth ablation electrode have substantially equal surface areas with respect to each other.

[0119] Clause 37. The end effector according to Clause 35 or 36, wherein each of the first ablation electrode, the second ablation electrode, the third ablation electrode, and the fourth ablation electrode defines its respective electrode area, and each electrode area begins to be positioned entirely on the right half of the planar body or entirely on the left half of the planar body.

[0120] Clause 38. An end effector according to any one of Clauses 1 to 37, wherein the planar body has an opening through the planar body between the first side and the second side 101b.

[0121] Clause 39. An end effector according to any one of Clauses 1 to 38, wherein the planar body includes a polymer encapsulation portion.

[0122] Clause 40. An end effector according to any one of Clauses 1 to 39, wherein the planar body comprises a plurality of elongated, thin polymer-filled regions lacking a framework and lacking electrical circuits.

[0123] Clause 41. The end effector according to any one of Clauses 1 to 40, wherein the planar body comprises a planar high dielectric layer that overlaps and is parallel to each of the multiple ablation electrodes.

[0124] Clause 42. The planar high dielectric layer comprises a ceramic-doped polymer, as described in Clause 41.

[0125] Clause 43. The end effector according to Clause 41 or 42, wherein the planar high dielectric layer extends over most of the entire width of the planar body.

[0126] Clause 44. An end effector according to any one of Clauses 41 to 43, wherein the planar body includes a planar high dielectric layer, lacks a framework, and lacks electrical circuits, and includes a longitudinally elongated region.

[0127] Clause 45. The planar body comprises at least one ceramic plate, as described in any one of Clauses 1 to 44.

[0128] Clause 46. The end effector according to Clause 45, wherein at least one ceramic plate includes a plurality of longitudinally extending ceramic plates.

[0129] Clause 47. The end effector according to Clause 46, wherein the multiple longitudinally extending ceramic plates are angled such that when the end effector retracts into the sheath, the multiple longitudinally extending ceramic plates overlap each other along their longitudinal sides.

[0130] Clause 48. An end effector as described in any one of Clauses 1 to 47, configured to provide pulsed-field ablation electrical pulses having a voltage of approximately 600 volts to approximately 1,200 volts between pairs of ablation electrodes among a plurality of ablation electrodes.

[0131] Clause 49. An end effector as described in any one of Clauses 1 through 48, configured to provide a damage depth of approximately 7.5 mm in a potato model.

[0132] Clause 50. An end effector as described in any one of Clauses 1 to 49, wherein the second ablation electrode is positioned on the second side of the planar body and does not overlap with the first ablation electrode.

[0133] Clause 51. An end effector as described in any one of Clauses 1 to 49, wherein the second ablation electrode is positioned on the first side of the planar body and does not overlap with the first ablation electrode.

[0134] Clause 52. The end effector according to Clause 50 or 51, wherein the planar body has a left half and a right half when viewed from a first side, the left half being to the left of a center line dividing the planar body in two along the longitudinal axis, and the right half being to the right of the center line, the first ablation electrode defining a first electrode region that is entirely located in the left half, and the second ablation electrode defining a second electrode region that is entirely located in the right half.

[0135] Clause 53. An end effector according to any one of Clauses 1 to 49, wherein the second ablation electrode is positioned on the second side of a planar body that overlaps with a large portion of the first ablation electrode.

[0136] Clause 54. An end effector according to any one of Clauses 1 to 53, comprising: a plurality of ablation electrodes, exactly two, three, or four ablation electrodes on a first side of a planar body and exactly two, three, or four ablation electrodes on a second side of a planar body.

[0137] Clause 55. The end effector according to Clause 54, comprising: a plurality of ablation electrodes, a precisely two ablation electrodes on a first side of a planar body and a precisely two ablation electrodes on a second side of a planar body.

[0138] Clause 56. The end effector according to Clause 54, comprising a plurality of ablation electrodes, specifically four ablation electrodes on a first side of a planar body and four ablation electrodes on a second side of a planar body.

[0139] Clause 57. An end effector according to any one of Clauses 54 to 56, wherein a plurality of ablation electrodes on the first side of the planar body precisely overlap with a plurality of ablation electrodes on the second side of the planar body.

[0140] Clause 58. A method for providing a pulsed-field ablation electrical signal to a planar end effector, comprising providing a first bipolar pulsed-field ablation electrical signal between a first ablation electrode and a second ablation electrode, wherein the first ablation electrode is positioned on the first side of the planar body of the planar end effector, and the second ablation electrode is positioned on the second side of the planar body and does not overlap with the first ablation electrode; and using the planar end effector, creating a wound in a potato model having a depth of approximately 7.5 mm.

[0141] Clause 59. Providing a first bipolar pulsed field ablation electrical signal is the method of Clause 58, which includes providing a pulse with a magnitude of about 1,200 volts over a duration of about 4 seconds.

[0142] Clause 60. Providing a first bipolar pulsed field ablation electrical signal is the method of Clause 58 or 59, which includes providing 60 bursts of electrical pulses.

[0143] Clause 61. The method according to any one of Clauses 58 to 60, further comprising providing a second bipolar pulsed-field ablation electrical signal between a third ablation electrode and a fourth ablation electrode, wherein the third ablation electrode is positioned on the first side of the planar body of a planar end effector and overlaps with the second ablation electrode, and the fourth ablation electrode is positioned on the second side of the planar body and overlaps with the second ablation electrode.

[0144] Clause 62. The method according to any one of Clauses 58 to 61, further comprising measuring cardiac electrical signals from diagnostic electrodes positioned on the first side of a planar body.

[0145] Clause 63. The method according to any one of Clauses 58 to 62, further comprising measuring tissue contact from a pair of tissue contact electrodes positioned on the first side of a planar body.

[0146] Clause 64. A bipolar pulse as described in any one of Clauses 58 to 63, including an inter-pulse delay of approximately 2 microseconds.

[0147] While exemplary embodiments of the subject matter included herein have been illustrated and described, further adaptations of the methods and systems described herein can be achieved by appropriate modifications without departing from the claims. For example, the end effector 100 may have an alternative shape or may include an alternative material, and the electrical signals used to achieve PFA may be modified to suit the specific shape and material of the end effector 100. Furthermore, where the above methods and steps describe specific events occurring in a particular order, the specific steps do not need to be performed in the order described, and are intended to be performed in any order, as long as the steps enable the embodiments to function for their intended purposes. Thus, the patent is intended to encompass such modifications as long as they are within the spirit of the disclosure or equivalent to the invention found in the claims. Some such modifications should be obvious to those skilled in the art. For example, the examples, embodiments, geometric shapes, materials, dimensions, proportions, steps, etc., discussed above are exemplary. Therefore, the claims should not be limited to the specific details of the structure and operation described in the specification and drawings.

[0148] [Implementation Method] (1) An end effector for a medical probe, wherein the end effector is A planar body extending along a longitudinal axis, comprising a first side and a second side opposite to the first side, The ablation electrode comprises a plurality of ablation electrodes, each including a first ablation electrode and a second ablation electrode, which are positioned on the first side of the planar body. The end effector is configured to provide a bipolar pulsed-field ablation electrical signal between the first ablation electrode and the second ablation electrode, An end effector wherein the first ablation electrode and the second ablation electrode each have a length of at least half the total length of the end effector when measured from the distal end of the end effector to the distal end of the shaft of the medical probe, and the respective lengths of the first ablation electrode and the second ablation electrode define the distal portion of the end effector. (2) The end effector according to Embodiment 1, further comprising at least one diagnostic electrode disposed on at least one of the first or second sides of the planar body, wherein the at least one diagnostic electrode is electrically isolated from the plurality of ablation electrodes and configured to receive electrical signals from tissue. (3) The end effector according to Embodiment 2, wherein the at least one diagnostic electrode comprises a plurality of pairs of diagnostic electrodes, each pair arranged diametrically along axes perpendicular to the longitudinal axis with respect to each other on the first and second sides, respectively. (4) The end effector according to Embodiment 1, further comprising a plurality of pairs of tissue contact electrodes spaced apart along the longitudinal axis, wherein each pair of tissue contact electrodes is located in close proximity to the distal portion of the end effector and on at least one of the first side or the second side. (5) A plurality of first ablation electrodes comprising four individual first ablation electrodes, wherein each first ablation electrode is one of the four individual first ablation electrodes, and each of the four first ablation electrodes can be connected to three other ablation electrodes to form one or more combined first ablation electrodes having a larger electrode area than any individual first ablation electrode, An end effector according to Embodiment 1, comprising a plurality of second ablation electrodes, each including four individual second ablation electrodes, wherein the second ablation electrode is one of the four individual second ablation electrodes, and each of the four second ablation electrodes can be connected to any of the other three second ablation electrodes to form a combined second ablation electrode having a larger electrode area than any individual second ablation electrode.

[0149] (6) The end effector according to Embodiment 1, wherein the first ablation electrode comprises a plurality of longitudinally elongated segments arranged to the left or right of each other, each of the plurality of longitudinally extending segments having a defined width and length, and the diagnostic electrode is positioned entirely within the width and length of each longitudinally extending segment of the first ablation electrode. (7) The end effector according to Embodiment 1, wherein each of the plurality of ablation electrodes has a meandering shape, and the meandering shape of the first ablation electrode is bent around at least three of the four sides of the diagnostic electrode. (8) The end effector according to Embodiment 1, wherein each of the plurality of ablation electrodes is coplanar with the planar body, provides a first plane to the end effector corresponding to the first side of the planar body, and provides a second plane to the end effector corresponding to the second side of the planar body. (9) The planar body is symmetrical with respect to a center line that divides the planar body in two along the longitudinal axis, The planar body has a left half and a right half when viewed from the first side, The aforementioned left half is to the left of the aforementioned center line, The aforementioned right half is to the right of the aforementioned center line, and, The end effector according to Embodiment 1, wherein the first ablation electrode defines a first electrode region that is fully positioned in the left half. (10) A pair of tissue contact electrodes arranged on the first side of the planar body, crossing the center line, The end effector according to embodiment 9, further comprising a reference electrode positioned on the first side of the planar body, crossing the center line.

[0150] (11) The end effector according to Embodiment 9, wherein the plurality of ablation electrodes further comprises a third ablation electrode and a fourth ablation electrode, and the end effector is configured to provide a bipolar pulsed field ablation electrical signal between the third ablation electrode and the fourth ablation electrode. (12) The end effector according to Embodiment 11, wherein the first ablation electrode, the second ablation electrode, the third ablation electrode, and the fourth ablation electrode have substantially equal surface areas with respect to each other. (13) The end effector according to Embodiment 11, wherein each of the first ablation electrode, the second ablation electrode, the third ablation electrode, and the fourth ablation electrode defines its respective electrode region, and each of the respective electrode regions begins to be positioned entirely on the right half of the planar body or entirely on the left half of the planar body. (14) The end effector according to Embodiment 1, wherein the planar body comprises a planar high dielectric layer that overlaps with and is parallel to each of the plurality of ablation electrodes. (15) The end effector according to Embodiment 14, wherein the planar high dielectric layer comprises a ceramic-doped polymer.

[0151] (16) The end effector according to Embodiment 14, wherein the planar body includes the planar high dielectric layer and includes a longitudinally elongated region that lacks a framework and electrical circuits. (17) The end effector according to Embodiment 1, wherein the planar body comprises a plurality of longitudinally extending ceramic plates, and the plurality of longitudinally extending ceramic plates are angled such that when the end effector retracts into the sheath, the plurality of longitudinally extending ceramic plates overlap each other in the longitudinal direction. (18) The end effector according to Embodiment 1, wherein the end effector is configured to provide pulsed-field ablation electrical pulses having a voltage of approximately 600 volts to approximately 1,200 volts between pairs of ablation electrodes among the plurality of ablation electrodes. (19) The second ablation electrode is positioned on the second side of the planar body and does not overlap with the first ablation electrode. The planar body has a left half and a right half when viewed from the first side, The aforementioned left half is to the left of the center line that divides the planar body in two along the longitudinal axis, The aforementioned right half is to the right of the aforementioned center line, The first ablation electrode defines a first electrode region that is completely positioned in the left half, The end effector according to Embodiment 1, wherein the second ablation electrode defines a second electrode region that is fully positioned in the right half. (20) The end effector according to Embodiment 1, wherein the plurality of ablation electrodes comprises exactly two, three, or four ablation electrodes on the first side of the planar body and exactly two, three, or four ablation electrodes on the second side of the planar body.

Claims

1. An end effector for a medical probe, wherein the end effector is A planar body extending along a longitudinal axis, comprising a first side and a second side opposite to the first side, The ablation electrode comprises a plurality of ablation electrodes, each including a first ablation electrode and a second ablation electrode, which are arranged on the first side of the planar body. The end effector is configured to provide a bipolar pulsed-field ablation electrical signal between the first ablation electrode and the second ablation electrode. An end effector wherein the first ablation electrode and the second ablation electrode each have a length of at least half the total length of the end effector when measured from the distal end of the end effector to the distal end of the shaft of the medical probe, and the respective lengths of the first ablation electrode and the second ablation electrode define the distal portion of the end effector.

2. The end effector according to claim 1, further comprising at least one diagnostic electrode disposed on at least one of the first or second sides of the planar body, wherein the at least one diagnostic electrode is electrically isolated from the plurality of ablation electrodes and is configured to receive electrical signals from tissue.

3. The end effector according to claim 2, wherein the at least one diagnostic electrode comprises a plurality of pairs of diagnostic electrodes, each pair being arranged diametrically along axes perpendicular to the longitudinal axis with respect to each other on the first and second sides, respectively.

4. The end effector according to claim 1, further comprising a plurality of pairs of tissue contact electrodes spaced apart along the longitudinal axis, wherein each pair of the plurality of tissue contact electrodes is located in close proximity to the distal portion of the end effector and on at least one of the first side or the second side.

5. A plurality of first ablation electrodes comprising four individual first ablation electrodes, wherein each of the four first ablation electrodes is one of the four individual first ablation electrodes, and each of the four first ablation electrodes can be connected to three other ablation electrodes to form one or more combined first ablation electrodes having a larger electrode area than any individual first ablation electrode, The end effector according to claim 1, comprising a plurality of second ablation electrodes, each including four individual second ablation electrodes, wherein the second ablation electrode is one of the four individual second ablation electrodes, and each of the four second ablation electrodes can be connected to any of the other three second ablation electrodes to form a combined second ablation electrode having a larger electrode area than any individual second ablation electrode.

6. The end effector according to claim 1, wherein the first ablation electrode comprises a plurality of longitudinally elongated segments arranged to the left or right of each other, each of the plurality of longitudinally extending segments having a defined width and length, and the diagnostic electrode is positioned entirely within the width and length of each longitudinally extending segment of the first ablation electrode.

7. The end effector according to claim 1, wherein each of the plurality of ablation electrodes has a meandering shape, and the meandering shape of the first ablation electrode is bent around at least three of the four sides of the diagnostic electrode.

8. The end effector according to claim 1, wherein each of the plurality of ablation electrodes is coplanar with the planar body, provides a first plane to the end effector corresponding to the first side of the planar body, and provides a second plane to the end effector corresponding to the second side of the planar body.

9. The planar body is symmetrical with respect to a center line that divides the planar body in two along the longitudinal axis. The planar body has a left half and a right half when viewed from the first side, The aforementioned left half is to the left of the aforementioned center line, The aforementioned right half is to the right of the aforementioned center line, and, The end effector according to claim 1, wherein the first ablation electrode defines a first electrode region that is completely located in the left half.

10. A pair of tissue contact electrodes are arranged on the first side of the planar body, crossing the aforementioned center line, The end effector according to claim 9, further comprising a reference electrode positioned on the first side of the planar body, crossing the center line.

11. The end effector according to claim 9, wherein the plurality of ablation electrodes further comprises a third ablation electrode and a fourth ablation electrode, and the end effector is configured to provide a bipolar pulsed field ablation electrical signal between the third ablation electrode and the fourth ablation electrode.

12. The end effector according to claim 11, wherein the first ablation electrode, the second ablation electrode, the third ablation electrode, and the fourth ablation electrode have substantially equal surface areas with respect to each other.

13. The end effector according to claim 11, wherein each of the first ablation electrode, the second ablation electrode, the third ablation electrode, and the fourth ablation electrode defines its respective electrode region, and each of the respective electrode regions begins to be positioned entirely on the right half of the planar body or entirely on the left half of the planar body.

14. The end effector according to claim 1, wherein the planar body comprises a planar high dielectric layer that overlaps with and is parallel to each of the plurality of ablation electrodes.

15. The end effector according to claim 14, wherein the planar high dielectric layer comprises a ceramic-doped polymer.

16. The end effector according to claim 14, wherein the planar body includes the planar high dielectric layer, lacks a framework, and lacks an electrical circuit, and includes a longitudinally elongated region.

17. The end effector according to claim 1, wherein the planar body comprises a plurality of longitudinally extending ceramic plates, and the plurality of longitudinally extending ceramic plates are angled such that when the end effector retracts into the sheath, the plurality of longitudinally extending ceramic plates overlap each other in their longitudinal directions.

18. The end effector according to claim 1, wherein the end effector is configured to provide a pulsed-field ablation electrical pulse having a voltage of approximately 600 volts to approximately 1,200 volts between pairs of ablation electrodes among the plurality of ablation electrodes.

19. The second ablation electrode is positioned on the second side of the planar body and does not overlap with the first ablation electrode. The planar body has a left half and a right half when viewed from the first side, The aforementioned left half is to the left of the center line that divides the planar body in two along the longitudinal axis, The aforementioned right half is to the right of the aforementioned center line, The first ablation electrode defines a first electrode region that is completely positioned in the left half, The end effector according to claim 1, wherein the second ablation electrode defines a second electrode region that is completely located in the right half.

20. The end effector according to claim 1, wherein the plurality of ablation electrodes comprises exactly two, three, or four ablation electrodes on the first side of the planar body and exactly two, three, or four ablation electrodes on the second side of the planar body.

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