Ablation system

Abstract

To provide a new technique related to catheter ablation.SOLUTION: An ablation system 1 includes a plurality of catheters 4 each having at least one electrode, a power supply unit 26 which is electrically connected to the plurality of catheters 4 and applies a voltage to the electrode of each catheter 4, and a control unit 28 which controls the power supply unit 26. The plurality of catheters 4 include at least a first catheter 5 and a second catheter 6 which are disposed with the target region 2 of the heart interposed therebetween. The control unit 28 controls the power supply unit 26 to apply a voltage between the electrode of the first catheter 5 and the electrode of the second catheter 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to ablation systems. [Background technology]

[0002] Patent Document 1 discloses an ablation system including an ablation catheter and a pulse waveform generator that delivers voltage pulses to the ablation catheter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-500170 Summary of the Invention [Problem to be solved by the invention]

[0004] As a result of extensive research, the present inventors have come up with a novel technique for catheter ablation.

[0005] The present disclosure has been made in light of these circumstances, and its purpose is to provide a novel technique related to catheter ablation. [Means for solving the problem]

[0006] One aspect of the present disclosure is an ablation system for performing ablation using irreversible electroporation. The ablation system includes a plurality of catheters, each having at least one electrode; a power supply unit electrically connected to the plurality of catheters and applying a voltage to the electrode of each catheter; and a control unit for controlling the power supply unit. The plurality of catheters include at least a first catheter and a second catheter positioned on either side of a target site in the heart. The control unit controls the power supply unit to apply a voltage between the electrode of the first catheter and the electrode of the second catheter.

[0007] Any combination of the above components, and conversion of the expression of the present disclosure into a method, device, system, etc., are also valid aspects of the present disclosure. [Effects of the Invention]

[0008] According to the present disclosure, a novel technique for catheter ablation can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an ablation system according to an embodiment. [Figure 2] FIG. 2 is a perspective view of an electrode assembly. [Figure 3] FIG. 10 is a diagram showing the timing of applying voltage to each electrode of the second catheter in the first application mode. [Figure 4] FIG. 10 is a schematic diagram showing an example of an interval between a positive voltage phase pulse and a negative voltage phase pulse. [Figure 5] FIG. 10 is a diagram illustrating a first example of electrode grouping. [Figure 6] Fig. 6(A) is a diagram illustrating a second example of electrode grouping, Fig. 6(B) is a diagram illustrating a third example of electrode grouping, and Fig. 6(C) is a diagram illustrating a fourth example of electrode grouping. [Figure 7] FIG. 10 is a schematic diagram of a tip portion of a catheter according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present disclosure will be described below with reference to preferred embodiments and drawings. The embodiments are illustrative and do not limit the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and should not be interpreted as limiting unless otherwise specified. Furthermore, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are intended to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from each drawing.

[0011] FIG. 1 is a schematic diagram of an ablation system 1 according to an embodiment. In FIG. 1, some of the components of the ablation system 1 are depicted as functional blocks. At least some of these functional blocks can be realized as a hardware configuration using elements and circuits such as a computer CPU and memory, and as a software configuration using a computer program or the like. Those skilled in the art will understand that these functional blocks can be realized in various ways by combining hardware and software.

[0012] The ablation system 1 performs a predetermined ablation on a target site 2 in a patient's heart. An example of the target site 2 is a site where arrhythmia is occurring. The ablation system 1 can also be used for ablation on other target sites 2. The ablation system 1 includes multiple catheters 4 and a power supply 8.

[0013] The multiple catheters 4 include at least a first catheter 5 and a second catheter 6. In one example, the multiple catheters 4 in this embodiment consist of only a first catheter 5 and a second catheter 6. This simplifies the procedure using the ablation system 1. It also reduces the cost of the ablation system 1. However, this configuration is not particularly limited, and the ablation system 1 may include three or more catheters 4. In the present disclosure, when there is no need to distinguish between the first catheter 5 and the second catheter 6, they may be simply referred to as "catheters 4."

[0014] The first catheter 5 and the second catheter 6 are positioned with a target site 2 in the heart sandwiched between them. In the present disclosure, "positioned with a target site 2 sandwiched between them" means that the first catheter 5 and the second catheter 6 are positioned in a positional relationship that allows a pulsed electric field required for treating the target site 2 by irreversible electroporation to be generated in the target site 2. The first catheter 5 and the second catheter 6 are only required to be positioned with the target site 2 interposed between them, and are not required to be in physical contact with the target site 2. For example, the first catheter 5 and the second catheter 6 are both positioned within a cardiac cavity. FIG. 1 illustrates, as an example, a state in which the first catheter 5 is inserted through the femoral artery and placed in the left ventricle, and the second catheter 6 is inserted through the femoral vein and placed in the right ventricle, with the target site 2 in the ventricular septum sandwiched between them.

[0015] The placement of the first catheter 5 and the second catheter 6 is not limited to this. For example, the first catheter 5 may be placed in the right ventricle, and the second catheter 6 may be placed in the left ventricle. Alternatively, one catheter 4 may be placed in the Vein of Marshall (VOM), and the other catheter 4 may be placed in the left atrium. Alternatively, one catheter 4 may be placed on the posterior wall side of the left atrium, and the other catheter 4 may be placed in the esophagus. Alternatively, one catheter 4 may be placed in the coronary sinus (CS), and the other catheter 4 may be placed on the mitra isthmus side of the left atrium or near the mitral valve. Alternatively, one catheter 4 may be placed in the pulmonary artery (PA), and the other catheter 4 may be placed in the right superior pulmonary vein (RSPV) or on the roof side of the left atrium. Alternatively, one catheter 4 may be placed in the aorta, and the other catheter 4 may be placed on the posterior wall side of the left atrium.

[0016] Each catheter 4 has a shaft 10, an electrode assembly 12, and a handle 14. The shaft 10 is made of a flexible tubular body, and at least the distal end is inserted into the patient's body. The shaft 10 is made of a known flexible material, including resins such as polyolefin, polytetrafluoroethylene, polyether block amide, and polyamide. The shaft 10 has a multi-lumen structure, for example, with multiple lumens. Various thin wires (not shown), such as conducting wires and operating wires, an inner tube 22 (see FIG. 2), which will be described later, and the like are inserted into the lumens.

[0017] An electrode assembly 12 is provided at the tip of the shaft 10. Fig. 2 is a perspective view of the electrode assembly 12. The electrode assembly 12 has a plurality of splines 16 and a plurality of electrodes 18. Note that Fig. 1 illustrates the splines 16 in a folded state, while Fig. 2 illustrates the splines 16 in an unfolded state.

[0018] Each spline 16 is a linear body extending in the axial direction of the shaft 10 and is made of the same flexible material as the shaft 10. The electrode assembly 12 shown in FIG. 2 has, as an example, a first spline 16a, a second spline 16b, a third spline 16c, a fourth spline 16d, a fifth spline 16e, and a sixth spline 16f, but the number of splines 16 is not limited to six and may be any plural number. In the present disclosure, when there is no need to distinguish the first spline 16a to the sixth spline 16f from one another, they may be simply referred to as "splines 16."

[0019] The splines 16 are arranged at intervals around the axis of the shaft 10. The distal end of each spline 16 is connected to a distal tip 20. The proximal end of each spline 16 is inserted into the shaft 10 from its distal end and fixed to the shaft 10. The distal tip 20 is connected to the distal end of an inner tube 22. The inner tube 22 is passed through the lumen of the shaft 10, and its proximal end is connected to the handle 14. The inner tube 22 can be advanced and retreated toward the distal end and proximal end of the shaft 10 by operating the handle 14.

[0020] When the inner tube 22 is retracted toward the proximal end of the shaft 10 with the splines 16 extended linearly, the distal tip 20 is displaced toward the proximal end of the shaft 10. This causes the splines 16 to curve outward, and the electrode assembly 12 assumes a basket shape. When the inner tube 22 is pushed toward the distal end of the shaft 10 with the splines 16 curved, the distal tip 20 is displaced toward the distal end of the shaft 10. This causes the splines 16 to straighten, and the electrode assembly 12 collapses. The term "basket shape" comes from the fact that the shape of the multiple splines 16 resembles the curved pattern on the surface of a basketball. In this disclosure, a catheter 4 having a basket-shaped electrode assembly 12 may be referred to as a "basket-type catheter."

[0021] Each spline 16 is provided with a plurality of electrodes 18. The plurality of electrodes 18 are arranged at predetermined intervals along the longitudinal direction of the spline 16. Each electrode 18 is ring-shaped and made of a metal with good electrical conductivity, such as platinum, gold, silver, copper, aluminum, or stainless steel, or an alloy thereof. The electrode assembly 12 shown in FIG. 2 has a first electrode 18a, a second electrode 18b, a third electrode 18c, and a fourth electrode 18d on each spline 16, as an example. However, the number of electrodes 18 is not limited to four, and may be at least one. In the present disclosure, when it is not necessary to distinguish the first electrode 18a to the fourth electrode 18d from one another, they may be simply referred to as "electrodes 18."

[0022] The tip of a conductor (not shown) is connected to each electrode 18. The conductor is passed through the lumen of the shaft 10, and the proximal end is connected to a connector (not shown) of the handle 14 shown in FIG. 1. A power supply 8 is electrically connected to each conductor via the connector of the handle 14. A voltage is applied to the plurality of electrodes 18 by the power supply 8, as will be described in detail later.

[0023] The handle 14 is provided at the base end of the shaft 10, and is disposed outside the body when the catheter 4 is in use, to be grasped or operated by the operator. The handle 14 has a main body portion grasped by the operator and an operating portion for advancing and retracting the inner tube 22. By operating the operating portion, the inner tube 22 can be displaced toward the base end relative to the shaft 10, thereby unfolding the electrode assembly 12, which is in a folded state, in a direction intersecting the axis of the shaft 10. Furthermore, by operating the operating portion, the inner tube 22 can be displaced toward the tip end relative to the shaft 10, thereby unfolding the electrode assembly 12, which is in an unfolded state. A connector is provided in the main body portion. The catheter 4 may have an irrigation mechanism that sprays irrigation fluid, such as saline, from the tip during ablation.

[0024] The power supply device 8 includes an input unit 24, a power supply unit 26, a control unit 28, and a display unit 30. The input unit 24 is configured with, for example, a dial, a button, a touch panel, etc., and is operated by the operator of the ablation system 1. The operator can input various setting values ​​and signals instructing operations to the power supply device 8 via the input unit 24. Note that the various setting values ​​may be set in advance, such as at the time of product shipment, and stored in the power supply device 8. A signal indicating the setting values, etc., is sent from the input unit 24 to the control unit 28.

[0025] The power supply unit 26 is electrically connected to the plurality of catheters 4, and applies an ablation voltage V to the electrode 18 of each catheter 4 in accordance with a control signal CTL sent from the control unit 28. out The power supply unit 26 is configured with a predetermined power supply circuit such as a switching regulator. The control unit 28 controls the operation of the entire power supply device 8 and executes predetermined arithmetic processing. The control unit 28 is configured with a microcomputer, for example. The control unit 28 controls the application of voltage Vout to each electrode 18 by sending a control signal CTL to the power supply unit 26. The display unit 30 displays various types of information to the outside. The display unit 30 can be configured with a liquid crystal display, a CRT display, an organic EL display, etc.

[0026] Next, the content of the control executed by the control unit 28 will be described. The ablation system 1 of this embodiment performs ablation on the target site 2 using irreversible electroporation (IRE). Because IRE is non-thermal, it is possible to suppress damage to tissues and nerves located around the target site 2. For example, when performing pulmonary vein dissection to treat atrial fibrillation, it is possible to suppress damage to the esophagus and phrenic nerve around the affected area, and to suppress the occurrence of complications such as esophageal fistula and phrenic nerve paralysis.

[0027] In IRE, pulsed electric field ablation (PFA) is performed. PFA is an ablation technique that kills cells by applying a pulsed electric field generated by applying a high voltage to the electrode 18 of the first catheter 5 and the electrode 18 of the second catheter 6, thereby forming a lesion at the target site 2. The electric field tends to reflect at the boundaries between tissues. This makes it possible to suppress damage to adjacent tissues when the target site 2 is cauterized.

[0028] With the electrode assembly 12 of each catheter 4 inserted into the patient's body via a blood vessel or the like and positioned near the target site 2, the control unit 28 controls the power supply unit 26 to apply a voltage between the electrode 18 of the first catheter 5 and the electrode 18 of the second catheter 6 according to one of the application modes described below. Applying a voltage between the electrode 18 of the first catheter 5 and the electrode 18 of the second catheter 6 allows for more efficient or more selective formation of a region in the target site 2 than applying a voltage between the electrode 18 of the catheter 4 and a return electrode plate placed outside the body. The control unit 28 can also implement a combination of the application modes described below. Each application mode differs in the way the electrode 18 of the first catheter 5 and the electrode 18 of the second catheter 6 are combined.

[0029] (First application mode) In the first application mode, the control unit 28 controls the power supply unit 26 to apply a voltage to the same electrode 18 of the first catheter 5, that is, to fix the electrode 18 to which the voltage is to be applied on the first catheter 5, while sequentially applying a voltage to each of the electrodes 18 to which the voltage is to be applied on the second catheter 6, one by one.

[0030] 3 is a diagram showing the timing of voltage application to each electrode 18 of the second catheter 6 in the first application mode. As an example, the controller 28 first determines the first electrode 18a on the first spline 16a of the first catheter 5 as the target to which the voltage is to be applied, and sequentially applies voltages to the first through third electrodes 18a, 18b, 18c, provided on one spline 16 of the second catheter 6. Next, while continuing to designate the first electrode 18a on the first spline 16a of the first catheter 5 as the target to which the voltage is to be applied, the controller 28 sequentially applies voltages to the first through third electrodes 18a, 18b, 18c, provided on another spline 16 of the second catheter 6. The controller 28 repeats this sequential application until finally applying voltages to all of the first through third electrodes 18a, 18b, 18c, provided on the electrode assembly 12 of the second catheter 6.

[0031] In the first application mode, as an example, the fourth electrode 18d on each spline 16 of each catheter 4 is excluded from the targets to which voltage is applied. The fourth electrode 18d is provided for potential measurement or as a spare in case the ablation range is wide. The fourth electrode 18d can also be omitted. Whether a voltage is being applied to each electrode 18 can be confirmed, for example, by connecting an oscilloscope to each electrode 18.

[0032] Specifically, a voltage is applied to the first electrode 18a on the first spline 16a of the first catheter 5. While this voltage application is maintained, voltages are applied to the first electrode 18a, second electrode 18b, and third electrode 18c on the first spline 16a of the second catheter 6, in that order. Next, voltages are applied to the first electrode 18a, second electrode 18b, and third electrode 18c on the second spline 16b of the second catheter 6, in that order. Next, voltages are applied to the first electrode 18a, second electrode 18b, and third electrode 18c on the third spline 16c of the second catheter 6, in that order. Next, voltages are applied to the first electrode 18a, second electrode 18b, and third electrode 18c on the fourth spline 16d of the second catheter 6, in that order. Next, voltages are applied to the first electrode 18a, second electrode 18b, and third electrode 18c on the fifth spline 16e of the second catheter 6, in that order. Finally, voltages are applied to the first electrode 18a, the second electrode 18b, and the third electrode 18c on the sixth spline 16f of the second catheter 6 in this order.

[0033] In FIG. 3, for convenience, the 18 electrodes 18 in the second catheter 6, from the first electrode 18a on the first spline 16a to the third electrode 18c on the sixth spline 16f, are numbered consecutively from 1 to 18. Furthermore, the power supply unit 26 of this embodiment applies voltage to each electrode 18 to generate a biphasic pulse (bipolar pulse). Therefore, a positive voltage phase pulse and a negative voltage phase pulse are applied to each electrode 18, and the polarity of each electrode 18 alternates. The voltage amplitude Am is, for example, 1000 V or more and 4000 V or less. The pulse width Δp is, for example, 0.1 μs or more and 100 μs or less.

[0034] In the first application mode of the present embodiment, one cycle is defined as the sequential application of voltage to all of the electrodes 18 to be applied with voltage in the second catheter 6, i.e., the first electrode 18a through the third electrode 18c on the first spline 16a through the sixth spline 16f. After completing the first cycle of sequential application of voltage to the first electrode 18a on the first spline 16a of the first catheter 5, the controller 28 performs a second cycle of sequential application of voltage to the second electrode 18b on the first spline 16a of the first catheter 5. Subsequently, after completing the second cycle of voltage application, the controller 28 performs a third cycle of sequential application of voltage to the third electrode 18c on the first spline 16a of the first catheter 5.

[0035] Thereafter, the control unit 28 sequentially switches the electrodes 18 to which voltage is applied in the first catheter 5 from the first electrodes 18a to the third electrodes 18c of the second spline 16b to the sixth spline 16f, thereby performing sequential application of voltage from the fourth to the eighteenth cycle. In the sequential application from the second cycle onwards, the order in which voltage is applied to the electrodes 18 of the second catheter 6 is the same as in the first cycle. The control unit 28 also controls the power supply unit 26 to repeat multiple sets of sequential voltage application, with the sequential application from the first cycle to the eighteenth cycle being counted as one set. The number of repeated sets can be set as appropriate based on the designer's empirical knowledge or on experiments, simulations, etc.

[0036] By sequentially applying a voltage to each electrode 18 of the first catheter 5 and the second catheter 6, it is possible to increase the region formed by each electrode 18 compared to applying a voltage to all electrodes 18 simultaneously. This is thought to be because, when a voltage is applied to all of the electrodes 18 at once, the current is dispersed among the electrodes 18, reducing the current density, whereas when a voltage is applied sequentially to each electrode 18, the current is concentrated in one electrode 18, increasing the current density. Furthermore, by sequentially applying a voltage to the electrodes 18 at intervals, it is possible to suppress the patient's body movements caused by PFA.

[0037] In the present embodiment, in both the first catheter 5 and the second catheter 6, voltage is applied to all of the electrodes 18 to be supplied with power on one spline 16 (i.e., the first electrode 18a to the third electrode 18c), and then the power supply destination moves to the electrodes 18 on the next spline 16. However, the order in which the voltages are applied is not limited as long as voltages are ultimately applied to all of the electrodes 18 to be supplied with power on the first catheter 5 and the second catheter 6. In other words, "sequential application" in the present disclosure means that voltages are applied by switching the target electrodes to which the voltage is applied one after another, and the arrangement of the electrodes 18 to be supplied with voltages may be the same as the order in which the voltages are applied, or may be unrelated to the order in which the voltages are applied.

[0038] For example, in both the first catheter 5 and the second catheter 6, the order in which voltages are applied to the first electrodes 18a to the third electrodes 18c may be different for each spline 16. Furthermore, after a voltage is applied to some of the electrodes 18 on one spline 16, the voltage application target may shift to the electrodes 18 on the next spline 16. For example, after a voltage is sequentially applied to the first electrodes 18a on each spline 16, a voltage may be sequentially applied to the second splines 16b on each spline 16, and finally a voltage may be sequentially applied to the third splines 16c on each spline 16. The order in which the splines 16 are subjected to voltage application is not limited. The order in which the voltages are applied may also be different for each rotation. Furthermore, in the first catheter 5 and the second catheter 6, some of the electrodes 18 or some of the splines 16 may be excluded from the voltage application target. Furthermore, some rotations may be omitted. Furthermore, in each set, at least one rotation may be performed multiple times continuously, intermittently, or randomly. The number of sets may be 1. In addition, before voltage is applied to all of the electrodes 18 to which voltage is to be applied in the second catheter 6, the electrodes 18 to which voltage is to be applied in the first catheter 5 may be switched.

[0039] Furthermore, control unit 28 may control power supply unit 26 to apply a voltage to any electrode 18 in second catheter 6 multiple times in succession, and then apply a voltage to another electrode 18 multiple times in succession. "Applying a voltage multiple times in succession" means applying a biphasic pulse to the same electrode 18 multiple times without applying a voltage to another electrode 18 in between. Hereinafter, multiple consecutive voltage applications to the same electrode 18 will be referred to simply as "consecutive application" where appropriate.

[0040] As an example of continuous application, in each revolution, first, a voltage is applied to the first electrode 18a on the first spline 16a of the second catheter 6 multiple times in succession. Next, a voltage is applied to the second electrode 18b on the first spline 16a multiple times in succession. Next, a voltage is applied to the third electrode 18c on the first spline 16a multiple times in succession. Next, the target to which the voltage is applied in the second catheter 6 is shifted to the second spline 16b, and a voltage is applied sequentially multiple times in succession to the first electrode 18a to the third electrode 18c on the second spline 16b. Thereafter, a voltage is also applied sequentially multiple times in succession to each of the electrodes 18 on the third spline 16c to the sixth spline 16f.

[0041] By continuously applying a voltage to the same electrode 18, the number of times the target to which the voltage is applied must be switched can be reduced compared to when the target to which the voltage is applied is switched for each voltage application. This simplifies the control performed by the control unit 28. The number of consecutive voltage applications can be set as appropriate based on the designer's empirical knowledge or experiments or simulations performed by the designer. The number of consecutive voltage applications may also be different for each electrode.

[0042] The control unit 28 may also control the power supply unit 26 to generate multiple pulse sets with different intervals between the positive voltage phase pulse and the negative voltage phase pulse applied to each electrode 18. FIG. 4 is a schematic diagram showing an example of the interval between the positive voltage phase pulse PVP and the negative voltage phase pulse NVP. As an example, the control unit 28 controls the power supply unit 26 to generate a first pulse set P1 followed by a second pulse set P2. The first pulse set P1 and the second pulse set P2 each correspond to one biphasic pulse BP.

[0043] In the first pulse set P1, the positive voltage phase pulse PVP and the negative voltage phase pulse NVP of the biphasic pulse BP are successively spaced apart by a predetermined first interval A1. In the second pulse set P2, the positive voltage phase pulse PVP and the negative voltage phase pulse NVP are successively spaced apart by a second interval A2 different from the first interval A1. Preferably, one of the first interval A1 and the second interval A2 is at least twice as long as the other. In the example shown in FIG. 4, the second interval A2 is at least twice as long as the first interval A1. Note that in each pulse set, the negative voltage phase pulse NVP may be generated before the positive voltage phase pulse PVP. Naturally, the trailing pulse of a leading pulse set does not also serve as the leading pulse of the trailing pulse set.

[0044] For example, the control unit 28 controls the power supply unit 26 to alternately generate the first pulse set P1 and the second pulse set P2. For example, in each rotation, the first pulse set P1 is generated by the first electrode 18a on the first spline 16a of the second catheter 6, the second pulse set P2 is generated by the second electrode 18b, and the first pulse set P1 is generated by the third electrode 18c. Subsequently, the second pulse set P2 is generated by the first electrode 18a on the second spline 16b of the second catheter 6, the first pulse set P1 is generated by the second electrode 18b, and the second pulse set P2 is generated by the third electrode 18c. This repetition of the first pulse set P1 and the second pulse set P2 is also performed for the first electrode 18a on the third spline 16c and thereafter.

[0045] The control unit 28 may also control the power supply unit 26 to generate a third pulse set P3 following the first pulse set P1 and the second pulse set P2. The third pulse set P3 corresponds to a biphasic pulse BP, similar to the first pulse set P1 and the second pulse set P2. In the third pulse set P3, a positive voltage phase pulse PVP and a negative voltage phase pulse NVP are successively spaced apart by a third interval A3 that is different from the first interval A1 and the second interval A2. For example, the third interval A3 is longer than the first interval A1 and the second interval A2.

[0046] For example, the control unit 28 controls the power supply unit 26 to repeat the first pulse set P1, the second pulse set P2, and the third pulse set P3 in this order. For example, in each rotation, the first pulse set P1 is generated by the first electrode 18a on the first spline 16a of the second catheter 6, the second pulse set P2 is generated by the second electrode 18b, and the third pulse set P3 is generated by the third electrode 18c. Subsequently, the first pulse set P1 is generated by the first electrode 18a on the second spline 16b of the second catheter 6, the second pulse set P2 is generated by the second electrode 18b, and the third pulse set P3 is generated by the third electrode 18c. This repetition of the first pulse set P1 to the third pulse set P3 is also performed for the first electrode 18a on the third spline 16c and thereafter.

[0047] The relationship between the lengths of the first interval A1, the second interval A2, and the third interval A3 is not limited to an increasing relationship in this order. For example, the first interval A1, the second interval A2, and the third interval A3 may be shorter in this order. The third interval A3 may be longer than one of the first interval A1 and the second interval A2 and shorter than the other. The third interval A3 may be the same length as the first interval A1 or the second interval A2. The first interval A1 and the second interval A2 may vary within the repetition period as long as consecutive pulses do not have the same length. The third interval A3 may also vary within the repetition period. An nth pulse set (n is an integer greater than or equal to 4) in which a positive voltage phase pulse PVP and a negative voltage phase pulse NVP are consecutive with an nth interval between them may be generated. The relationship of the nth interval to the first interval A1 and the second interval A2 is the same as that of the third interval A3.

[0048] Furthermore, when the interval between adjacent pulse sets is interval T, the relationship in magnitude between interval T and the first interval A1 to third interval A3 satisfies, for example, the following condition: That is, interval T is longer than the interval between the positive voltage phase pulse PVP and the negative voltage phase pulse NVP in two adjacent pulse sets. For example, interval T between first pulse set P1 and second pulse set P2 is longer than first interval A1 and second interval A2. Furthermore, interval T between second pulse set P2 and third pulse set P3 is longer than second interval A2 and third interval A3. As a more preferred example, interval T is at least twice, and more preferably 5 to 50 times, the longer of the intervals between the positive voltage phase pulse PVP and the negative voltage phase pulse NVP in two adjacent pulse sets. For example, when the first interval A1 is greater than the second interval A2, the interval T between the first pulse set P1 and the second pulse set P2 is preferably at least twice the first interval A1, and more preferably at least 5 times and at most 50 times the first interval A1.

[0049] Furthermore, control unit 28 may also control power supply unit 26 to generate a plurality of pulse sets in each electrode 18 of first catheter 5, with different intervals between the positive voltage phase pulse and the negative voltage phase pulse.

[0050] (Second application mode) In the second application mode, the control unit 28 divides the multiple electrodes 18 to which a voltage is to be applied in the second catheter 6 into multiple electrode groups G, the number of which is less than the number of electrodes 18. Each electrode group G includes one or more electrodes 18, and at least one electrode group G includes two or more electrodes 18. The control unit 28 then controls the power supply unit 26 to sequentially apply a voltage to each electrode group G in the second catheter 6 while applying a voltage to the same electrode 18 in the first catheter 5, i.e., while fixing the electrode 18 to which a voltage is to be applied in the first catheter 5. When an electrode group G includes multiple electrodes 18, applying a voltage to that electrode group G causes the voltage to be applied to each electrode 18 simultaneously. Here, "applied simultaneously" means that the states in which voltages are applied to the electrodes 18 overlap at least temporarily.

[0051] 5 is a diagram illustrating a first example of grouping of electrodes 18. In the first example, at least some of the electrodes 18 belonging to the same electrode group G are arranged on the same spline 16. Furthermore, the electrodes 18 of at least two electrode groups G are arranged on the same spline 16. Then, an electrode 18 belonging to another electrode group G is arranged between two electrodes 18 belonging to the same electrode group G.

[0052] For example, the first electrode 18a and the third electrode 18c on the first spline 16a of the second catheter 6 are assigned to the first electrode group G1. The second electrode 18b and the fourth electrode 18d on the first spline 16a are assigned to the second electrode group G2. Therefore, on the first spline 16a, the second electrode 18b belonging to the second electrode group G2 is arranged between the first electrode 18a and the third electrode 18c belonging to the first electrode group G1, and the third electrode 18c belonging to the first electrode group G1 is arranged between the second electrode 18b and the fourth electrode 18d belonging to the second electrode group G2.

[0053] Similarly, for the second spline 16b to the sixth spline 16f, the first electrode 18a and the third electrode 18c belong to the first electrode group G1, and the second electrode 18b and the fourth electrode 18d belong to the second electrode group G2. Therefore, the second catheter 6 has 12 electrode groups G. In the present disclosure, when it is not necessary to distinguish between the first electrode group G1 to the n-th electrode group Gn (n is an integer of 1 or greater), they may be simply referred to as "electrode groups G."

[0054] For example, a voltage is applied to the first electrode 18a on the first spline 16a of the first catheter 5. While this voltage application is maintained, a voltage is applied to the first electrode group G1 on the first spline 16a of the second catheter 6. Next, a voltage is applied to the second electrode group G2 on the first spline 16a of the second catheter 6. Next, the target to which the voltage is applied is shifted to the second spline 16b, and voltages are applied to the first electrode group G1 and then the second electrode group G2. Thereafter, the target to which the voltage is applied is shifted to the third spline 16c to the sixth spline 16f in order, and voltages are applied to the first electrode group G1 and then the second electrode group G2 for each spline 16 in that order.

[0055] In the second application mode of the present embodiment, one cycle is defined as the sequential application of voltage to the 12 electrode groups G of the second catheter 6. After completing the first cycle of sequential application of voltage to the first electrode 18a on the first spline 16a of the first catheter 5, the controller 28 performs a second cycle of sequential application of voltage to the second electrode 18b on the first spline 16a of the first catheter 5. After completing the second cycle of voltage application, the controller 28 performs a third cycle of sequential application of voltage to the third electrode 18c on the first spline 16a of the first catheter 5. After completing the third cycle of voltage application, the controller 28 performs a fourth cycle of sequential application of voltage to the fourth electrode 18d on the first spline 16a of the first catheter 5.

[0056] Furthermore, the control unit 28 sequentially switches the electrodes 18 to be applied with voltage in the first catheter 5 from the first electrodes 18a to the fourth electrodes 18d of the second spline 16b to the sixth spline 16f, thereby performing sequential voltage application from the fifth to the 24th cycle. In the sequential voltage application from the second cycle onwards, the order in which voltage is applied to each electrode group G of the second catheter 6 is the same as in the first cycle. The control unit 28 also controls the power supply unit 26 to repeat multiple sets of sequential voltage application, with the sequential voltage application from the first cycle to the 24th cycle being counted as one set. The number of repeated sets can be set as appropriate based on the designer's empirical knowledge or on experiments, simulations, etc.

[0057] By sequentially applying a voltage to each electrode group G of the second catheter 6, in other words, by switching the target to which the voltage is applied in units of electrode group G, it is possible to form a larger region with each electrode 18 than when applying a voltage to all electrodes 18 simultaneously. Furthermore, in the first application mode in which a voltage is sequentially applied to each of the multiple electrodes 18, it is possible to form a larger region with each electrode 18 than in the second application mode in which a voltage is applied to each electrode group G. However, depending on the spacing between two adjacent electrodes 18, the magnitude of the applied voltage, and other factors, it may be possible to form a sufficiently large region by applying a voltage to each electrode group G, for example, a region large enough to overlap with the adjacent region. In this case, the method of sequentially applying a voltage to each electrode 18 may have the disadvantage of taking longer to complete ablation than the advantage of being able to form a larger region.

[0058] In contrast, by sequentially applying a voltage to the electrode group G, the time required for ablation can be shortened compared to sequentially applying a voltage to the electrodes 18 one by one. Alternatively, if the time required to complete ablation is the same, the number of times the voltage is applied can be increased compared to sequentially applying a voltage to the electrodes 18 one by one, thereby making the region larger. Furthermore, compared to sequentially applying a voltage to the electrodes 18 one by one, the power supply circuit for switching the target to which the voltage is applied can be simplified. This allows the power supply device 8 to be made smaller. Furthermore, it also makes it easier to add more electrodes 18.

[0059] Furthermore, when a voltage is applied simultaneously to two adjacent electrodes 18, regions of the same potential overlap, which can result in a situation where no current flows in the overlapping portion. Since no region is formed in the portion where no current flows, a gap in the region occurs between the two adjacent electrodes 18. To address this issue, in this embodiment, an electrode 18 belonging to another electrode group G is disposed between two electrodes 18 belonging to the same electrode group G. This prevents regions of the same potential from overlapping when a voltage is applied to two electrodes 18 of the same electrode group G. Therefore, it is possible to prevent gaps in the region from occurring.

[0060] The same electrode 18 may be assigned to two or more different electrode groups G. For example, the first electrode 18a and the second electrode 18b may be assigned to the first electrode group G1, and the second electrode 18b and the third electrode 18c may be assigned to the second electrode group G2. That is, the second electrode 18b, which is located between the first electrode 18a and the third electrode 18c, may be assigned to both the first electrode group G1 and the second electrode group G2. This also prevents the formation of gaps between regions. That is, even if a gap is formed between the first electrode 18a and the second electrode 18b due to the application of a voltage to the first electrode group G1, the gap can be filled by the region formed by the second electrode 18b when a voltage is applied to the second electrode group G2.

[0061] 6(A) is a diagram illustrating a second example of grouping of electrodes 18. In the second example, at least some of the electrodes 18 belonging to the same electrode group G are arranged on different splines 16. For example, in the second catheter 6, the first spline 16a and the second spline 16b form one pair, the third spline 16c and the fourth spline 16d form one pair, and the fifth spline 16e and the sixth spline 16f form one pair. In each pair, the first electrodes 18a are assigned to the first electrode group G1, the second electrodes 18b are assigned to the second electrode group G2, the third electrodes 18c are assigned to the third electrode group G3, and the fourth electrodes 18d are assigned to the fourth electrode group G4.

[0062] Therefore, in the second example, the two electrodes 18 belonging to the same electrode group G are aligned in the axial direction of the shaft 10. More specifically, in a state where at least the splines 16 are deployed and no forces other than the forces for deploying the splines 16 are acting on each spline 16, the two electrodes 18 belonging to the same electrode group G are aligned in the axial direction of the shaft 10. In the present disclosure, the alignment of the two electrodes 18 in the axial direction of the shaft 10 means that at least a portion of the two electrodes 18 overlaps with each other when viewed from a direction perpendicular to the axial direction of the shaft 10.

[0063] In each rotation, the control unit 28 first applies voltage to the first spline 16a and the second spline 16b, and applies voltage to the first electrode group G1, the second electrode group G2, the third electrode group G3, and the fourth electrode group G4 on those splines in that order. Next, the control unit 28 shifts the voltage application target to the third spline 16c and the fourth spline 16d, and applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines in that order. After that, the control unit 28 shifts the voltage application target to the fifth spline 16e and the sixth spline 16f, and applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines in that order.

[0064] The second example also makes it possible to shorten the time required for ablation, as in the first example. Furthermore, the power supply circuit can be simplified. Furthermore, the distance between the regions where the electrodes 18 are arranged on two adjacent splines 16 tends to be wider than the distance between adjacent electrodes 18 on the same spline 16. Therefore, the second example makes it possible to further prevent gaps from forming between the regions.

[0065] 6(B) is a diagram illustrating a third example of grouping the electrodes 18. In the third example, at least some of the electrodes 18 belonging to the same electrode group G are arranged on different splines 16. Also, in the third example, two electrodes 18 belonging to the same electrode group G but arranged on different splines 16 are offset in the axial direction of the shaft 10. More specifically, when at least the splines 16 are deployed and no forces other than the forces for deploying the splines 16 are applied to each spline 16, the two electrodes 18 belonging to the same electrode group G are offset in the axial direction of the shaft 10. In the present disclosure, two electrodes 18 being offset in the axial direction of the shaft 10 means that the two electrodes 18 do not entirely overlap when viewed from a direction perpendicular to the axial direction of the shaft 10.

[0066] For example, in the second catheter 6, the first spline 16a and the second spline 16b form one set, the third spline 16c and the fourth spline 16d form one set, and the fifth spline 16e and the sixth spline 16f form one set. The first electrode 18a on one spline 16 and the fourth electrode 18d on the other spline 16 in each set are assigned to a first electrode group G1. The second electrode 18b on one spline 16 and the third electrode 18c on the other spline 16 in each set are assigned to a second electrode group G2. The third electrode 18c on one spline 16 and the second electrode 18b on the other spline 16 in each set are assigned to a third electrode group G3. Furthermore, the fourth electrode 18d on one spline 16 and the first electrode 18a on the other spline 16 in each set belong to a fourth electrode group G4.

[0067] In each rotation, the control unit 28 first applies voltage to the first spline 16a and the second spline 16b, and applies voltage to the first electrode group G1, the second electrode group G2, the third electrode group G3, and the fourth electrode group G4 on those splines in that order. Next, the control unit 28 shifts the voltage application target to the third spline 16c and the fourth spline 16d, and applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines in that order. After that, the control unit 28 shifts the voltage application target to the fifth spline 16e and the sixth spline 16f, and applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines in that order.

[0068] The third example also makes it possible to shorten the time required for ablation, as in the second example. It also simplifies the power supply circuit. Furthermore, the third example makes it possible to suppress the occurrence of gaps between regions more effectively than the second example.

[0069] 6(C) is a diagram illustrating a fourth example of grouping the electrodes 18. In the fourth example, at least some of the electrodes 18 belonging to the same electrode group G are arranged on different splines 16. In addition, in the fourth example, two electrodes 18 belonging to the same electrode group G are arranged on splines 16 that are not adjacent to each other. In other words, one of the two electrodes 18 belonging to the same electrode group G is arranged on a predetermined spline 16. Furthermore, the other electrode 18 is arranged on a spline 16 other than the spline 16 adjacent to that spline 16.

[0070] For example, in the second catheter 6, the first spline 16a and the fourth spline 16d form one pair, the second spline 16b and the fifth spline 16e form one pair, and the third spline 16c and the sixth spline 16f form one pair. The first electrodes 18a in each pair are assigned to a first electrode group G1, the second electrodes 18b are assigned to a second electrode group G2, the third electrodes 18c are assigned to a third electrode group G3, and the fourth electrodes 18d are assigned to a fourth electrode group G4. Therefore, for example, when attention is focused on the first electrode group G1, which is arranged in the pair of the first spline 16a and the fourth spline 16d, the two first electrodes 18a belonging to the first electrode group G1 are arranged on first splines 16a and fourth splines 16d that are not adjacent to each other.

[0071] In each rotation, the control unit 28 first applies voltage to the first spline 16a and the fourth spline 16d, and applies voltage to the first electrode group G1, the second electrode group G2, the third electrode group G3, and the fourth electrode group G4 on those splines in that order. Next, the control unit 28 shifts the voltage application target to the second spline 16b and the fifth spline 16e, and applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines in that order. After that, the control unit 28 shifts the voltage application target to the third spline 16c and the sixth spline 16f, and applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines in that order.

[0072] The fourth example also shortens the time required for ablation, as in the second and third examples. Furthermore, the power supply circuit can be simplified. Furthermore, the fourth example can prevent gaps between regions more effectively than the third example. Furthermore, the fourth example can widen the interval between the previous application of voltage to each electrode 18 and the next application of voltage. In particular, by forming a pair of splines 16 facing each other across the inner tube 22, the interval can be further widened. As a result, excessive increases in the temperature of each electrode 18 can be prevented.

[0073] As a fifth example, the multiple electrodes 18 in the second catheter 6 are divided into electrode groups G for each spline 16. That is, the first electrodes 18a to 4th electrodes 18d on the first spline 16a belong to the first electrode group G1. The first electrodes 18a to 4th electrodes 18d on the second spline 16b belong to the second electrode group G2. The first electrodes 18a to 4th electrodes 18d on the third spline 16c belong to the third electrode group G3. The first electrodes 18a to 4th electrodes 18d on the fourth spline 16d belong to the fourth electrode group G4. The first electrodes 18a to 4th electrodes 18d on the fifth spline 16e belong to the fifth electrode group G5. The first electrodes 18a to 4th electrodes 18d on the sixth spline 16f belong to the sixth electrode group G6.

[0074] In the first catheter 5 and the second catheter 6, some of the electrodes 18 and some of the splines 16 may be excluded from the targets of voltage application. Also, some laps may be omitted. Furthermore, in each set, at least one lap may be performed multiple times continuously, intermittently, or randomly. The number of sets may be one. Furthermore, the electrodes 18 to which voltage is applied in the first catheter 5 may be switched before voltage is applied to all of the electrode groups G to which voltage is applied in the second catheter 6.

[0075] For example, the fourth electrode 18d on each spline 16 may be excluded from the target to which a voltage is applied. In this case, the second electrode group G2 in the first example is composed of only the second electrode 18b. The second and fourth examples do not include the fourth electrode group G4. The first electrode group G1 and the fourth electrode group G4 in the third example are composed of only the first electrode 18a. In the fifth example, each electrode group G is composed of the first to third electrodes 18a to 18c. The fourth electrode 18d excluded from the target to which a voltage is applied can be used for potential measurement or as a spare when the ablation range is wide, as in the first application mode.

[0076] Furthermore, in the first to fifth examples, the combination of splines 16, the combination of electrodes 18, the order of voltage application, the number of electrodes 18 belonging to each electrode group G, etc. may be changed as appropriate. For example, in the third example, in each set of splines 16, the first electrode 18a on one spline 16 and the second spline 16b on the other spline 16 may be assigned to a first electrode group G1, the second electrode 18b on one spline 16 and the third electrode 18c on the other spline 16 may be assigned to a second electrode group G2, the third electrode 18c on one spline 16 and the fourth electrode 18d on the other spline 16 may be assigned to a third electrode group G3, and the fourth electrode 18d on one spline 16 and the first electrode 18a on the other spline 16 may be assigned to a fourth electrode group G4.

[0077] In the fourth example, the first spline 16a and the fifth spline 16e may be grouped together, the second spline 16b and the fourth spline 16d may be grouped together, and the third spline 16c and the sixth spline 16f may be grouped together. In the fifth example, multiple splines 16 may belong to the same electrode group G. In the first to fifth examples, the order of the electrode groups G to which voltages are applied is not particularly limited. For example, if the multiple electrodes 18 are divided into four electrode groups G, the order may be the first electrode group G1, the third electrode group G3, the second electrode group G2, and the fourth electrode group G4. The order of voltage application may also vary for each electrode group G or each circumference.

[0078] Two or more of Examples 1 to 5 may be combined. For example, Examples 1 and 3 may be combined, and the first electrode 18a and the third electrode 18c on the first spline 16a and the first electrode 18a and the third electrode 18c on the second spline 16b may be assigned to the first electrode group G1. Furthermore, the plurality of electrodes 18 to which a voltage is applied in the first catheter 5 may be divided into a plurality of electrode groups G, the number of which is less than the number of electrodes 18, and a voltage may be applied between the electrode group G of the first catheter 5 and the electrode group G of the second catheter 6.

[0079] Furthermore, as in the first application mode, the control unit 28 may control the power supply unit 26 to apply a voltage to an arbitrary electrode group G in the second catheter 6 multiple times in succession, and then apply a voltage to another electrode group G multiple times in succession. For example, in the fifth example described above, for each rotation, a voltage is applied multiple times in succession in the order of the first electrode group G1, the second electrode group G2, the third electrode group G3, the fourth electrode group G4, the fifth electrode group G5, and the sixth electrode group G6. This achieves the same effect as in the first application mode. Note that the number of consecutive electrode groups G may differ.

[0080] As in the first application mode, the controller 28 may control the power supply 26 to generate a plurality of pulse sets in which the intervals between the positive voltage phase pulse PVP and the negative voltage phase pulse NVP applied to each electrode group G are different. For example, in the fifth example described above, in each cycle, the first pulse set P1 is generated by the first electrode group G1, the second pulse set P2 is generated by the second electrode group G2, the first pulse set P1 is generated by the third electrode group G3, the second pulse set P2 is generated by the fourth electrode group G4, the first pulse set P1 is generated by the fifth electrode group G5, and the second pulse set P2 is generated by the sixth electrode group G6. The controller 28 may also control the power supply 26 to generate a plurality of pulse sets in which the intervals between the positive voltage phase pulse and the negative voltage phase pulse are different for each electrode 18 of the first catheter 5.

[0081] The embodiments of the present disclosure have been described in detail above. The above-described embodiments merely illustrate specific examples of implementing the present disclosure. The content of the embodiments does not limit the technical scope of the present disclosure, and many design modifications, such as changing, adding, or deleting components, are possible within the scope of the concept of the present disclosure defined in the claims. A new embodiment with design modifications will combine the effects of the combined embodiments and modifications. In the above-described embodiments, the content that allows such design modifications is emphasized by using notations such as "in this embodiment" or "in this embodiment," but design modifications are also permitted even in content without such notation. Any combination of the components included in each embodiment is also valid as an aspect of the present disclosure. Hatching on cross sections in the drawings does not limit the material of the hatched object.

[0082] (Variation) FIG. 7 is a schematic diagram of the distal end of a catheter 4 according to a modified example. In the embodiment, both the first catheter 5 and the second catheter 6 are basket-type catheters, but this configuration is not limiting. For example, at least one of the first catheter 5 and the second catheter 6 may not have a spline 16 at the distal end of the shaft 10, and may have a structure in which the electrode 18 is provided directly on the outer circumferential surface of the shaft 10, as shown in FIG. 7. In the present disclosure, a catheter 4 in which the electrode 18 is provided on the outer circumferential surface of the shaft 10 may be referred to as a "straight-type catheter." The first catheter 5 and the second catheter 6 may both be basket-type catheters, or one may be a basket-type catheter and the other a straight-type catheter, or both may be straight-type catheters. Furthermore, the catheter 4 may have a known structure other than a basket-type or straight-type catheter.

[0083] In the catheter 4 according to this modification, for example, a first electrode 18a, a second electrode 18b, a third electrode 18c, a fourth electrode 18d, a fifth electrode 18e, and a sixth electrode 18f are arranged on the shaft 10. The number and arrangement of the electrodes 18 can be changed as appropriate. When the second application mode is applied to the catheter 4 according to this modification, for example, the first electrode 18a, the third electrode 18c, and the fifth electrode 18e are assigned to a first electrode group G1, and the second electrode 18b, the fourth electrode 18d, and the sixth electrode 18f are assigned to a second electrode group G2. The controller 28 then applies a voltage to the first electrode group G1 and then applies a voltage to the second electrode group G2. For example, first electrode 18a and fourth electrode 18d belong to first electrode group G1, second electrode 18b and fifth electrode 18e belong to second electrode group G2, and third electrode 18c and sixth electrode 18f belong to third electrode group G3. Then, control unit 28 applies voltages to first electrode group G1, second electrode group G2, and third electrode group G3 in that order. This configuration also achieves the same effects as the embodiment.

[0084] (Other variations) All of the electrodes 18 to which a voltage is applied in the second catheter 6 may be assigned to one electrode group G, and a voltage may be applied between at least one electrode 18 in the first catheter 5 and the electrode group G in the second catheter 6. Alternatively, all of the electrodes 18 to which a voltage is applied in each of the first catheter 5 and the second catheter 6 may be grouped into one electrode group G, and a voltage may be applied between the pair of electrode groups G. Alternatively, each of the first catheter 5 and the second catheter 6 may have only one electrode 18 to which a voltage is applied, and a voltage may be applied between the pair of electrodes 18. Furthermore, in each of the first and second application modes, the number of electrodes 18 fixed to the target to which a voltage is applied in the first catheter 5 is not limited to one, and a voltage may be simultaneously applied to multiple electrodes 18 in the first catheter 5, and the target to which the voltage is applied may be fixed to the multiple electrodes 18.

[0085] The configurations of the catheter 4 and the power supply 8 can be modified as appropriate. For example, the distal end of the shaft 10 of the catheter 4 may be bendable in one direction or multiple directions by operating the handle 14. The shapes and numbers of the splines 16 and the electrodes 18 are not particularly limited. Furthermore, when the catheter 4 has multiple splines 16, the electrodes 18 may be provided on at least one spline 16 and / or the shaft 10. That is, the electrodes 18 may be provided only on the splines 16, only on the shaft 10, or on both the splines 16 and the shaft 10. Furthermore, when the electrodes 18 are provided on the splines 16, the electrodes 18 may be provided on only some or all of the splines 16. Furthermore, the power supply unit 26 may apply a voltage to each electrode 18 to generate a monophasic pulse. The control of the power supply unit 26 by the control unit 28 may be realized by hardware (circuitry) or software (program). When realized by software, the software is composed of a group of programs for causing a computer to execute each function. Each program may be installed in the computer in advance, or may be installed in the computer from a network or a recording medium, for example.

[0086] The embodiments may be specified by the following items. [1st item] An ablation system (1) for performing ablation using irreversible electroporation, comprising: a plurality of catheters (4) each having at least one electrode (18); a power supply unit (26) electrically connected to the plurality of catheters (4) and applying a voltage to the electrodes (18) of each catheter (4); a control unit (28) that controls the power supply unit (26), The plurality of catheters (4) include at least a first catheter (5) and a second catheter (6) disposed on opposite sides of a target site (2) in the heart; The control unit (28) controls the power supply unit (26) to apply a voltage between the electrode (18) of the first catheter (5) and the electrode (18) of the second catheter (6). Ablation system (1). [Second item] The plurality of catheters (4) consists of only a first catheter (5) and a second catheter (6); The ablation system (1) described in item 1. [3rd item] At least one of the first catheter (5) and the second catheter (6) has a shaft (10) and an electrode (18) provided on the outer circumferential surface of the shaft (10). 1st or 2nd item ablation system (1). [4th item] At least one of the first catheter (5) and the second catheter (6) has a shaft (10), a plurality of splines (16) arranged in a circumferential direction of the shaft (10), and an electrode (18) provided on at least one of the spline (16) and the shaft (10), or both. An ablation system (1) according to any one of items 1 to 3. [Item 5] The second catheter (6) has a plurality of electrodes (18) to which a voltage is applied, The control unit (28) controls the power supply unit (26) to sequentially apply voltage to each of the electrodes (18) of the second catheter (6) one by one while fixing the electrode (18) to which the voltage is to be applied in the first catheter (5). An ablation system (1) according to any one of items 1 to 4. [Item 6] The second catheter (6) has a plurality of electrodes (18) to which a voltage is applied, the control unit (28) divides the plurality of electrodes (18) of the second catheter (6) into a plurality of electrode groups (G) whose number is less than the number of the electrodes (18), and controls the power supply unit (26) to sequentially apply a voltage to each electrode group (G) while fixing the electrode (18) to which a voltage is to be applied in the first catheter (5); An ablation system (1) according to any one of items 1 to 5. [Explanation of symbols]

[0087] 1 ablation system, 2 target site, 4 catheter, 5 first catheter, 6 second catheter, 10 shaft, 16 spline, 18 electrode, 26 power supply unit, 28 control unit, G electrode group.

Claims

1. 1. An ablation system for performing ablation using irreversible electroporation, comprising: a plurality of catheters each having at least one electrode; a power supply unit electrically connected to the plurality of catheters and configured to apply a voltage to the electrodes of each catheter; a control unit that controls the power supply unit, the plurality of catheters include at least a first catheter and a second catheter disposed across a target site in the heart; the control unit controls the power supply unit to apply a voltage between the electrode of the first catheter and the electrode of the second catheter. Ablation system.

2. the plurality of catheters consists of only the first catheter and the second catheter; The ablation system of claim 1 .

3. At least one of the first catheter and the second catheter has a shaft and the electrode provided on an outer circumferential surface of the shaft. The ablation system according to claim 1 or 2.

4. At least one of the first catheter and the second catheter has a shaft, a plurality of splines arranged in a circumferential direction of the shaft, and the electrode provided on at least one of the spline and the shaft, or both. The ablation system according to claim 1 or 2.

5. the second catheter has a plurality of the electrodes to which a voltage is applied, the control unit controls the power supply unit to sequentially apply voltage to each electrode of the second catheter one by one while fixing the electrode to which voltage is to be applied in the first catheter. The ablation system according to claim 1 or 2.

6. the second catheter has a plurality of the electrodes to which a voltage is applied, the control unit divides the plurality of electrodes of the second catheter into a plurality of electrode groups whose number is less than the number of the electrodes, and controls the power supply unit to sequentially apply a voltage to each electrode group while fixing the electrode to which a voltage is to be applied in the first catheter. The ablation system according to claim 1 or 2.

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