Ablation system

Abstract

An ablation system 1 includes: a catheter 4 having three or more electrodes; a power supply unit 26 that is electrically connected to the catheter 4 and that applies a voltage to the plurality of electrodes; and a control unit 28 that, upon dividing the plurality of electrodes 18 into a plurality of electrode groups the number of which is smaller than the number of the electrodes 18, controls the power supply unit 26 so as to sequentially apply a voltage to each of the electrode groups.

Description

Ablation System

[0001] The present disclosure relates to ablation systems.

[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.

[0003] Special table 2019-500170 publication

[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.

[0006] One aspect of the present disclosure is an ablation system comprising: a catheter having three or more electrodes; a power supply unit electrically connected to the catheter and configured to apply a voltage to the electrodes; and a control unit configured to divide the electrodes into a number of electrode groups less than the number of electrodes and control the power supply unit to sequentially apply a voltage to each electrode group.

[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.

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

[0009] Fig. 4(A) is a schematic diagram of an ablation system according to an embodiment; Fig. 4(B) is a perspective view of an electrode assembly; Fig. 4(C) is a diagram illustrating a first example of electrode grouping; Fig. 4(A) is a diagram illustrating a second example of electrode grouping; Fig. 4(B) is a diagram illustrating a third example of electrode grouping; Fig. 4(C) is a diagram illustrating a fourth example of electrode grouping; Fig. 4(C) is a schematic diagram of a tip portion of a catheter according to a modified example.

[0010] The present disclosure will be described below with reference to the drawings based on preferred embodiments. 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 represent 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 an affected area 2 of a patient. The affected area 2 may be, for example, an organ experiencing arrhythmia. The ablation system 1 may also be used for ablation on other affected areas 2. The ablation system 1 includes a catheter 4, a return electrode 6, and a power supply 8.

[0013] The catheter 4 includes a shaft 10, an electrode assembly 12, and a handle 14. The shaft 10 is 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 lead wires and operating wires, as well as an inner tube 22 (see FIG. 2), which will be described later, are inserted into the lumens.

[0014] 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 three or more 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.

[0015] 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 Figure 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 number as long as there is a plurality of splines. 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."

[0016] 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 end of an inner tube 22 is connected to the distal tip 20. 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.

[0017] When the inner tube 22 is retracted toward the proximal end of the shaft 10 with each spline 16 extending linearly, the distal tip 20 is displaced toward the proximal end of the shaft 10. This causes each spline 16 to curve and bulge 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 each spline 16 curved, the distal tip 20 is displaced toward the distal end of the shaft 10. This causes each spline 16 to become linear, and the electrode assembly 12 is folded. 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.

[0018] Each spline 16 is provided with a plurality of electrodes 18. The electrodes 18 are arranged at predetermined intervals along the length 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, as an example, a first electrode 18a, a second electrode 18b, a third electrode 18c, and a fourth electrode 18d on each spline 16. However, the number of electrodes 18 is not limited to four, and the electrode assembly 12 may include three or more electrodes. In the present disclosure, when it is not necessary to distinguish the first to fourth electrodes 18a to 18d from one another, they may be simply referred to as "electrodes 18."

[0019] 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 unit 8 is electrically connected to each conductor via the connector of the handle 14. As will be described in detail later, a voltage is applied to the plurality of electrodes 18 by the power supply unit 8.

[0020] The handle 14 is provided at the proximal 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 proximal 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 distal end relative to the shaft 10, thereby unfolding the electrode assembly 12, which is in an unfolded state. A connector is provided on the main body portion. The catheter 4 may have an irrigation mechanism that sprays irrigation fluid, such as saline, from the distal end during ablation.

[0021] The return electrode 6 is attached to the patient's body surface during ablation. The return electrode 6 is also electrically connected to a power supply 8. During ablation, a voltage is applied to each electrode 18 and the return electrode 6, thereby performing ablation.

[0022] 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. Signals indicating the setting values, etc., are sent from the input unit 24 to the control unit 28.

[0023] The power supply unit 26 applies an ablation voltage V to the plurality of electrodes 18 and the return electrode plate 6 in accordance with a control signal CTL sent from the control unit 28. ｏｕｔThe 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 the electrode 18 and the return electrode 6 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 is configured with a liquid crystal display, a CRT display, an organic EL display, etc.

[0024] 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 affected area 2 by irreversible electroporation (IRE). Because IRE is non-thermal, it is possible to suppress damage to tissues and nerves located around the affected area 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.

[0025] IRE involves pulsed electric field ablation (PFA). PFA is an ablation technique that kills cells by applying a pulsed electric field generated by applying a high voltage to each electrode 18 and the return electrode 6, i.e., forms a lesion in the affected area 2. The electric field tends to be reflected at the boundaries between tissues. This prevents damage to adjacent tissues when the affected area is cauterized.

[0026] After the electrode assembly 12 is inserted into the patient's body via a blood vessel or the like and positioned at the affected area 2, the control unit 28 controls the power supply unit 26 to sequentially apply a voltage to each electrode 18 according to the rules described below. That is, the control unit 28 divides the electrodes 18 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. When an electrode group G includes multiple electrodes 18, applying a voltage to that electrode group G results in the voltage being applied to each electrode 18 simultaneously. Here, "simultaneously applied" means that the states in which voltages are applied to the electrodes 18 overlap at least temporarily. The sequential application of voltages to each electrode group G can be confirmed, for example, by connecting an oscilloscope to each electrode 18.

[0027] 3 is a diagram illustrating a first example of grouping of the 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.

[0028] For example, the first electrode 18a and the third electrode 18c on the first spline 16a 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.

[0029] Similarly, for the second spline 16b to the sixth spline 16f, the first electrode 18a and the third electrode 18c are assigned to the first electrode group G1, and the second electrode 18b and the fourth electrode 18d are assigned to the second electrode group G2. Thus, the electrode assembly 12 has 12 electrode groups G. In the present disclosure, when it is not necessary to distinguish the first electrode group G1 to the n-th electrode group Gn (n is an integer of 1 or greater) from one another, they may be simply referred to as "electrode groups G."

[0030] The control unit 28 applies a voltage to the first electrode group G1 on the first spline 16a, then applies a voltage to the second electrode group G2 on the first spline 16a. Next, the target to which the voltage is to be 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 to be applied is shifted to the third spline 16c to the sixth spline 16f, and voltages are applied to the first electrode group G1 and then the second electrode group G2 for each spline 16 in that order.

[0031] In this embodiment, the power supply unit 26 applies a 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.

[0032] As an example, the control unit 28 controls the power supply unit 26 to perform multiple sequential voltage applications, with one cycle being one sequential voltage application to the 12 electrode groups G. The control unit 28 also controls the power supply unit 26 to perform multiple sets of sequential voltage applications, with multiple cycles being one set. The number of cycles in one set and the number of repeated sets can be set appropriately based on experiments by the designer. For example, the number of cycles in one set is 2 to 1,000 cycles, and the number of sets is 2 to 100 sets. The number of cycles may be one cycle, and the number of sets may be one set.

[0033] By sequentially applying a voltage to each electrode group G, it is possible to increase the region that can be formed by each electrode 18 compared to when a voltage is simultaneously applied to all of the electrodes 18, in other words, to all of the electrode groups G. 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 multiple electrodes 18, resulting in a decrease in current density, whereas when a voltage is applied sequentially to each electrode group G, the current is concentrated in one electrode group G, resulting in an increase in current density.

[0034] Furthermore, when a voltage is applied sequentially to each of the multiple electrodes 18, a larger region can be formed by each electrode 18 than when 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, applying a voltage to each electrode group G may also be able to form a sufficiently large region, for example, a region large enough to overlap with adjacent regions. In this case, the method of sequentially applying a voltage to each of the electrodes 18 may have a disadvantage of taking longer to complete ablation than the advantage of being able to form a larger region.

[0035] In contrast, by sequentially applying voltage to the electrode group G, the time required for ablation can be shortened compared to sequentially applying voltage to the electrodes 18 one by one. Alternatively, if the time required to complete ablation is the same, the number of times voltage is applied can be increased compared to sequentially applying voltage to the electrodes 18 one by one, thereby making the region larger. Furthermore, compared to sequentially applying voltage to the electrodes 18 one by one, the power supply circuit for switching the target to which voltage is applied can be simplified. This allows for the miniaturization of the power supply device 8. Furthermore, it also makes it easier to add more electrodes 18.

[0036] Furthermore, when a voltage is applied simultaneously to two adjacent electrodes 18, regions of the same potential overlap, potentially resulting in a situation in which no current flows through 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.

[0037] 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, 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. In this case, the occurrence of a gap in the region can be suppressed. That is, even if a gap in the region 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.

[0038] 4A is a diagram illustrating a second example of grouping the 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.

[0039] For example, the first spline 16a and the second spline 16b are grouped together, the third spline 16c and the fourth spline 16d are grouped together, and the fifth spline 16e and the sixth spline 16f are grouped together. The first electrodes 18a in each group are assigned to the first electrode group G1, the second electrodes 18b in each group are assigned to the second electrode group G2, the third electrodes 18c in each group are assigned to the third electrode group G3, and the fourth electrodes 18d in each group are assigned to the fourth electrode group G4. Therefore, in the second example, two electrodes 18 belonging to the same electrode group G are aligned in the axial direction of the shaft 10. More specifically, when at least the splines 16 are deployed and no forces other than those for deploying the splines 16 are acting on the splines 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, two electrodes 18 being aligned 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.

[0040] The control unit 28 first applies voltage to the first spline 16a and the second spline 16b, and sequentially 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. Next, the control unit 28 shifts the target of voltage application to the third spline 16c and the fourth spline 16d, and sequentially applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines. Thereafter, the control unit 28 shifts the target of voltage application to the fifth spline 16e and the sixth spline 16f, and sequentially applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines.

[0041] As with the first example, the second example also shortens the time required for ablation. 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 can further prevent gaps from occurring between the regions.

[0042] 4B is a diagram illustrating a third example of grouping of 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 each other when viewed from a direction perpendicular to the axial direction of the shaft 10.

[0043] For example, 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. In addition, 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.

[0044] The control unit 28 first applies voltage to the first spline 16a and the second spline 16b, and sequentially 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. Next, the control unit 28 shifts the target of voltage application to the third spline 16c and the fourth spline 16d, and sequentially applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines. Thereafter, the control unit 28 shifts the target of voltage application to the fifth spline 16e and the sixth spline 16f, and sequentially applies voltage to the first electrode group G1 to the fourth electrode group G4 on those splines.

[0045] The third example also shortens the time required for ablation, as in the second example. It also simplifies the power supply circuit. Furthermore, the third example can further reduce the occurrence of gaps between regions than the second example.

[0046] 4C 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 another spline 16 excluding the spline 16 adjacent to that spline 16.

[0047] For example, the first spline 16 a and the fourth spline 16 d are grouped together, the second spline 16 b and the fifth spline 16 e are grouped together, and the third spline 16 c and the sixth spline 16 f are grouped together. In each group, the first electrodes 18 a belong to a first electrode group G1, the second electrodes 18 b belong to a second electrode group G2, the third electrodes 18 c belong to a third electrode group G3, and the fourth electrodes 18 d belong to a fourth electrode group G4. Therefore, for example, when attention is focused on the first electrode group G1 that is arranged in the pair of the first spline 16 a and the fourth spline 16 d, two first electrodes 18 a belonging to the first electrode group G1 are arranged on first splines 16 a and fourth splines 16 d that are not adjacent to each other.

[0048] The control unit 28 first applies voltage to the first spline 16a and the fourth spline 16d in this order, applying voltage to the first electrode group G1, the second electrode group G2, the third electrode group G3, and the fourth electrode group G4 on these splines. Next, the control unit 28 shifts the target of voltage application to the second spline 16b and the fifth spline 16e, applying voltages to the first electrode group G1 to the fourth electrode group G4 on these splines in this order. Thereafter, the control unit 28 shifts the target of voltage application to the third spline 16c and the sixth spline 16f, applying voltages to the first electrode group G1 to the fourth electrode group G4 on these splines in this order.

[0049] 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 pairing the splines 16 that face 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.

[0050] 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. The fourth electrode 18d excluded from the target to which a voltage is applied can be used for measuring potential or as a spare electrode in case the ablation range is wide.

[0051] Furthermore, in the first to fourth 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.

[0052] In the fourth example, the first spline 16a and the fifth spline 16e may be a pair, the second spline 16b and the fourth spline 16d may be a pair, and the third spline 16c and the sixth spline 16f may be a pair. The order of voltage application in the first to fourth examples may be, for example, the first electrode group G1, the third electrode group G3, the second electrode group G2, and the fourth electrode group G4. The order of power supply to the electrodes 18 may differ for each electrode group G. The power supply unit 26 may apply voltage to each electrode 18 to generate a monophasic pulse. The shapes and numbers of the splines 16 and the electrodes 18 are not limited.

[0053] It is also possible to combine the first and third examples, for example, so that 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 belong to the first electrode group G1.

[0054] Furthermore, the configurations of the catheter 4 and the power supply device 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 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, for example, pre-installed in the computer, or may be installed into the computer from a network or a recording medium.

[0055] 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.

[0056] 5 is a schematic diagram of the tip of a catheter 4 according to a modified example. The catheter 4 according to the modified example does not have a spline 16 at the tip of the shaft 10, and multiple electrodes 18 are arranged on the shaft 10. As an 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 of electrodes 18 can be changed as appropriate.

[0057] The control unit 28 groups the electrodes 18 so that an electrode 18 belonging to another electrode group G is disposed between two electrodes 18 belonging to the same electrode group G. For example, the first electrode 18a, the third electrode 18c, and the fifth electrode 18e are assigned to the first electrode group G1, and the second electrode 18b, the fourth electrode 18d, and the sixth electrode 18f are assigned to the second electrode group G2. The control unit 28 then applies a voltage to the first electrode group G1, and then applies a voltage to the second electrode group G2.

[0058] For example, the first electrode 18a and the fourth electrode 18d belong to the first electrode group G1, the second electrode 18b and the fifth electrode 18e belong to the second electrode group G2, and the third electrode 18c and the sixth electrode 18f belong to the third electrode group G3. The control unit 28 applies voltages to the first electrode group G1, the second electrode group G2, and the third electrode group G3 in this order. This configuration can also achieve the same effects as the embodiment.

[0059] Embodiments may be specified by the following items: [Item 1] An ablation system (1) comprising: a catheter (4) having three or more electrodes (18); a power supply unit (26) electrically connected to the catheter (4) and applying a voltage to the electrodes (18); and a control unit (28) that divides the electrodes (18) into a number of electrode groups (G) less than the number of electrodes (18) and controls the power supply unit (26) to sequentially apply a voltage to each electrode group (G). [Item 2] The ablation system (1) described in item 1, wherein the catheter (4) has a shaft (10) and a number of splines (16) arranged in a direction around the axis of the shaft (10), and at least some of the electrodes (18) belonging to the same electrode group (G) are arranged on the same spline (16). [Item 3] The ablation system (1) according to item 2, wherein electrodes (18) of at least two electrode groups (G) are arranged on the same spline (16), and an electrode (18) belonging to another electrode group (G) is arranged between two electrodes (18) belonging to the same electrode group (G). [Item 4] The ablation system (1) according to item 1, wherein the catheter (4) has a shaft (10) and a plurality of splines (16) arranged in a direction around the axis of the shaft (10), and at least some of the plurality of electrodes (18) belonging to the same electrode group (G) are arranged on different splines (16). [Item 5] The ablation system (1) according to item 4, wherein two electrodes (18) belonging to the same electrode group (G) and arranged on different splines (16) are offset in the axial direction of the shaft (10). [Item 6] The ablation system (1) according to item 4 or 5, wherein two electrodes (18) belonging to the same electrode group (G) are arranged on splines (16) that are not adjacent to each other. [Item 7] The ablation system (1) according to item 1, wherein the catheter (4) has a shaft (10), and the plurality of electrodes (18) are arranged on the shaft (10).[Item 8] The ablation system (1) according to item 7, wherein an electrode (18) belonging to another electrode group (G) is arranged between two electrodes (18) belonging to the same electrode group (G).

[0060] The present disclosure can be utilized in ablation systems.

[0061] 1 Ablation system, 4 Catheter, 8 Power supply unit, 10 Shaft, 12 Electrode assembly, 16 Spline, 18 Electrode, 26 Power supply unit, 28 Control unit.

Claims

1. An ablation system comprising: a catheter having three or more electrodes; a power supply unit electrically connected to the catheter and applying a voltage to the electrodes; and a control unit that divides the electrodes into a number of electrode groups less than the number of electrodes, and controls the power supply unit to sequentially apply a voltage to each electrode group.

2. The ablation system according to claim 1, wherein the catheter has a shaft and a plurality of splines arranged in a direction around the axis of the shaft, and at least a portion of the plurality of electrodes belonging to the same electrode group are arranged on the same spline.

3. The ablation system of claim 2, wherein the electrodes of at least two of the electrode groups are arranged on the same spline, and an electrode belonging to another electrode group is arranged between two of the electrodes belonging to the same electrode group.

4. The ablation system according to claim 1, wherein the catheter has a shaft and a plurality of splines arranged in a circumferential direction of the shaft, and at least some of the electrodes belonging to the same electrode group are arranged on different splines.

5. The ablation system according to claim 4, wherein two of the electrodes belonging to the same electrode group and arranged on different splines are offset in the axial direction of the shaft.

6. The ablation system according to claim 4 or 5, wherein two of the electrodes belonging to the same electrode group are arranged on splines that are not adjacent to each other.

7. The ablation system of claim 1, wherein the catheter has a shaft, and the plurality of electrodes are disposed on the shaft.

8. The ablation system according to claim 7, wherein the electrode belonging to another electrode group is disposed between two of the electrodes belonging to the same electrode group.

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