Power supply device and ablation system

Abstract

To provide a novel technology related to a catheter ablation method.SOLUTION: A power supply device includes: a power supply part that applies a voltage to an electrode so as to generate a biphasic pulse BP, the power supply part being electrically connected to a catheter including an electrode; and a control part that controls the power supply part so as to generate a second pulse set P2 successively to a first pulse set P1. In the first pulse set P1, a positive voltage phase pulse PVP and a negative voltage phase pulse NVP in the biphasic pulse BP continue with a predetermined first gap A1. In the second pulse set P2, a positive voltage phase pulse PVP and a negative voltage phase pulse NVP continue with a second gap A2 different from the first gap A1.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a power supply and an ablation system. [Background technology]

[0002] Patent Document 1 discloses an ablation system including an ablation catheter and a pulse waveform generator that delivers a voltage pulse 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 investigations, 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 has an object to provide a novel technique related to catheter ablation. [Means for solving the problem]

[0006] An embodiment of the present disclosure is a power supply device comprising: a power supply unit electrically connected to a catheter having electrodes and configured to apply a voltage to the electrodes to generate biphasic pulses; and a control unit configured to control the power supply unit to generate a first pulse set in which a positive voltage phase pulse and a negative voltage phase pulse in the biphasic pulses are successively spaced apart by a predetermined first interval, followed by a second pulse set in which the positive voltage phase pulse and the negative voltage phase pulse are successively spaced apart by a second interval different from the first interval.

[0007] Another aspect of the present disclosure is an ablation system comprising a catheter having an electrode and a power supply device according to the above aspect.

[0008] Any combination of the above components and any conversion of the expression of the present disclosure between a method, an apparatus, a system, etc. are also valid as aspects of the present disclosure. Effect of the Invention

[0009] According to the present disclosure, a novel technique for catheter ablation can be provided. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of an ablation system according to an embodiment. [Diagram 2] FIG. 2 is a perspective view of an electrode assembly. [Diagram 3] FIG. 4 is a diagram showing the timing of voltage application to each electrode. [Figure 4] 10 is a schematic diagram showing an example of an interval between a positive voltage phase pulse and a negative voltage phase pulse. FIG. [Diagram 5] 13 is a schematic diagram showing another example of the interval between a positive voltage phase pulse and a negative voltage phase pulse. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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, members, and processes shown in each drawing are given the same reference numerals, and duplicated descriptions are omitted as appropriate. In addition, the scale and shape of each part shown in each drawing are set for convenience to facilitate explanation, and are not to be interpreted as being limiting unless otherwise specified. In addition, 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. In addition, some of the members that are not important in explaining the embodiment in each drawing are omitted.

[0012] 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 by elements and circuits such as a computer CPU and memory, and as a software configuration by 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.

[0013] The ablation system 1 performs a predetermined ablation on an affected area 2 of a patient. An example of the affected area 2 is an organ in which arrhythmia occurs. The ablation system 1 can 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 unit 8.

[0014] The catheter 4, as an example, 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 tip side 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 having, for example, multiple lumens. Various thin wires (not shown) such as conductors and operating wires, an inner tube 22 (see FIG. 2), which will be described later, and the like are inserted into the lumens.

[0015] 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, and Fig. 2 illustrates the splines 16 in an expanded state.

[0016] 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 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 as an example, but the number of splines 16 is not limited to six and may be any number. In the present disclosure, when it is not necessary to distinguish the first spline 16a to the sixth spline 16f from one another, they may be simply referred to as "splines 16."

[0017] The splines 16 are disposed at intervals from one another in the axial direction 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 tip 20 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.

[0018] When the inner tube 22 is pulled toward the base end of the shaft 10 with each spline 16 extending linearly, the distal tip 20 is displaced toward the base 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.

[0019] A plurality of electrodes 18 are provided on each spline 16. The plurality of electrodes 18 are arranged at predetermined intervals from each other in the longitudinal direction of the spline 16. Each electrode 18 is ring-shaped and made of a metal having good electrical conductivity, such as platinum, gold, silver, copper, aluminum, 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, but the number of electrodes 18 is not limited to four. In the present disclosure, when it is not necessary to distinguish the first electrode 18a to the fourth electrode 18d from each other, they may be simply referred to as "electrodes 18".

[0020] The tip of a conductor wire (not shown) is connected to each electrode 18. The conductor wire is passed through the lumen of the shaft 10, and the base 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 wire via the connector of the handle 14. A voltage is applied to the multiple electrodes 18 by the power supply unit 8, as will be described in detail later.

[0021] The handle 14 is provided at the base end of the shaft 10, and is disposed outside the body when the catheter 4 is used, and is grasped or operated by an operator. The handle 14 has a main body portion grasped by the operator and an operation portion for advancing and retracting the inner tube 22. By operating the operation portion, the inner tube 22 can be displaced toward the base end side relative to the shaft 10. As a result, the electrode assembly 12 in the folded state unfolds in a direction intersecting with the axis of the shaft 10. Also, by operating the operation portion, the inner tube 22 can be displaced toward the tip side relative to the shaft 10. As a result, the electrode assembly 12 in the unfolded state is folded. The connector is provided in the main body portion. The catheter 4 may have an irrigation mechanism that sprays an irrigation fluid, such as saline, from the tip during ablation.

[0022] The return electrode 6 is attached to the body surface of the patient 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.

[0023] 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 composed of, for example, a dial, a button, a touch panel, etc., and is operated by an 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 preset at the time of product shipment, etc., and held 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.

[0024] The power supply unit 26 supplies the ablation voltage V to the electrode 18 and the return electrode 6 in accordance with a control signal CTL sent from the control unit 28. outThe power supply unit 26 is composed of 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 composed of a microcomputer, for example. The control unit 28 controls the application of the voltage Vout to the electrode 18 and the counter electrode 6 by sending a control signal CTL to the power supply unit 26. The display unit 30 displays various information to the outside. The display unit 30 is composed of a liquid crystal display, a CRT display, an organic EL display, etc.

[0025] Next, the contents 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). Since 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 esophageal fistula and phrenic nerve paralysis.

[0026] 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 each electrode 18 and the return electrode 6, that is, forms a lesion in the affected area 2. The electric field tends to be reflected at the boundary between tissues. Therefore, it is possible to suppress damage to adjacent tissues when the affected area is cauterized.

[0027] With the electrode assembly 12 inserted into the patient's body via a blood vessel or the like and placed at the affected area 2, the control unit 28, for example, controls the power supply unit 26 to sequentially apply a voltage to each electrode 18. FIG. 3 is a diagram showing the timing of voltage application to each electrode 18. Note that FIG. 3 also shows a schematic diagram of the interval between a positive voltage phase pulse and a negative voltage phase pulse applied to each electrode 18. This interval will be described in detail later with reference to FIG. 4. The sequential application of voltage to each electrode 18 can be confirmed, for example, by connecting an oscilloscope to each electrode 18.

[0028] The control unit 28 sequentially applies voltage to the first electrode 18a to the third electrode 18c provided on one spline 16. Then, the control unit 28 sequentially applies voltage to the first electrode 18a to the third electrode 18c provided on another spline 16. The control unit 28 repeats this sequential application, and finally applies voltage to all the first electrodes 18a to the third electrodes 18c of the electrode assembly 12. In this embodiment, the fourth electrode 18d on each spline 16 is excluded from the target to which the voltage is applied. The fourth electrode 18d is provided for potential measurement or as a spare when the ablation range is wide. The fourth electrode 18d can be omitted.

[0029] Specifically, first, a voltage is applied to the first electrode 18a, the second electrode 18b, and the third electrode 18c on the first spline 16a in this order. Next, a voltage is applied to the first electrode 18a, the second electrode 18b, and the third electrode 18c on the second spline 16b in this order. Next, a voltage is applied to the first electrode 18a, the second electrode 18b, and the third electrode 18c on the third spline 16c in this order. Next, a voltage is applied to the first electrode 18a, the second electrode 18b, and the third electrode 18c on the fourth spline 16d in this order. Next, a voltage is applied to the first electrode 18a, the second electrode 18b, and the third electrode 18c on the fifth spline 16e in this order. Finally, a voltage is applied to the first electrode 18a, the second electrode 18b, and the third electrode 18c on the sixth spline 16f in this order. In FIG. 3, for the sake of convenience, the 18 electrodes 18 from the first electrode 18a of the first spline 16a to the third electrode 18c of the sixth spline 16f are numbered consecutively from 1 to 18.

[0030] The power supply unit 26 of this embodiment applies a voltage to each electrode 18 to generate a biphasic pulse (bipolar pulse). Thus, 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 value Am is, for example, 1000V or more and 4000V or less. The pulse width Δp is, for example, 0.1μs or more and 100μs or less.

[0031] In the present embodiment, the sequential application of voltage to all electrodes 18 to be powered in the electrode assembly 12, that is, the first electrodes 18a to the third electrodes 18c in the first spline 16a to the sixth spline 16f, is regarded as one revolution. The control unit 28 controls the power supply unit 26 to execute the sequential application of voltage for multiple revolutions. The control unit 28 also controls the power supply unit 26 to repeat the sequential application of voltage for multiple sets, with multiple revolutions being regarded as one set. The number of revolutions in one set and the number of sets to be repeated can be appropriately set based on experiments by a designer. For example, the number of revolutions in one set is 2 or more and 1000 or less, and the number of sets is 2 or more and 100 or less. The number of revolutions may be one revolution, and the number of sets may be one set.

[0032] By sequentially applying a voltage to each electrode 18, it is possible to increase the region that can be formed by each electrode 18 compared to the case where a voltage is simultaneously applied to all of the multiple electrodes 18. This is believed to be because, when a voltage is applied to all of the multiple electrodes 18 at once, the current flows dispersedly among the multiple electrodes 18, decreasing 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. In addition, by sequentially applying a voltage to the multiple electrodes 18 at intervals, it is possible to suppress the occurrence of body movements of the patient due to PFA.

[0033] Next, the interval between the positive voltage phase pulse PVP and the negative voltage phase pulse NVP applied to each electrode 18 will be described. 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. The control unit 28 of this embodiment controls the power supply unit 26 to generate the second pulse set P2 following the first pulse set P1. That is, the first pulse set P1 and the second pulse set P2 are continuous with each other. The first pulse set P1 and the second pulse set P2 each correspond to one biphasic pulse BP.

[0034] In the first pulse set P1, the positive voltage phase pulse PVP and the negative voltage phase pulse NVP in the biphasic pulse BP are successive with 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 successive with a second interval A2 different from the first interval A1. Preferably, the first interval A1 and the second interval A2 are 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. Also, naturally, the trailing pulse of the leading pulse set does not also serve as the leading pulse of the trailing pulse set.

[0035] For example, the control unit 28 controls the power supply unit 26 to alternately repeat the first pulse set P1 and the second pulse set P2. As an example, the first pulse set P1 is generated by the first electrode 18a on the first spline 16a, 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, 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 of the third spline 16c and onwards.

[0036] The control unit 28 may also control the power supply unit 26 as follows. FIG. 5 is a schematic diagram showing another example of the interval between the positive voltage phase pulse PVP and the negative voltage phase pulse NVP. That is, the control unit 28 controls the power supply unit 26 to generate the 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, the positive voltage phase pulse PVP and the negative voltage phase pulse NVP are successively spaced apart by a third interval A3 different from the first interval A1 and the second interval A2. As an example, the third interval A3 is longer than the first interval A1 and the second interval A2.

[0037] 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. As an example, the first pulse set P1 is generated by the first electrode 18a on the first spline 16a, 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. Then, the first pulse set P1 is generated by the first electrode 18a on the second spline 16b, 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 on the first electrode 18a of the third spline 16c and onwards.

[0038] The relationship of the lengths of the first interval A1, the second interval A2, and the third interval A3 is not limited to the relationship of increasing in this order. For example, the first interval A1, the second interval A2, and the third interval A3 may be shorter in this order. Also, the third interval A3 may be longer than one of the first interval A1 and the second interval A2 and shorter than the other. Furthermore, the third interval A3 may be the same length as the first interval A1 or the second interval A2. Also, the first interval A1 and the second interval A2 may change during the repetition period as long as the successive intervals do not have the same length. Similarly, the third interval A3 may change during the repetition period. Also, an nth pulse set (n is an integer of 4 or more) in which a positive voltage phase pulse PVP and a negative voltage phase pulse NVP are successive with an nth interval 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.

[0039] In addition, when the interval between adjacent pulse sets is the interval T, the magnitude relationship between the interval T and the first interval A1 to the third interval A3 satisfies the following condition, for example. That is, the 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, the interval T between the first pulse set P1 and the second pulse set P2 is longer than the first interval A1 and the second interval A2. In addition, the interval T between the second pulse set P2 and the third pulse set P3 is longer than the second interval A2 and the third interval A3. As a more preferable example, the interval T is at least twice as long as the longer of the intervals between the positive voltage phase pulse PVP and the negative voltage phase pulse NVP in two adjacent pulse sets, and more preferably is 5 times or more and 50 times or less. For example, when the first interval A1 is larger 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.

[0040] In the present embodiment, after a 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), the power supply destination shifts to the electrodes 18 on the next spline 16, but the order of power supply is not limited as long as a voltage is ultimately applied to all of the electrodes 18 to be supplied with power in the electrode assembly 12. For example, after a voltage is applied to some of the electrodes 18 to be supplied with power on one spline 16, the power supply destination may shift to the electrodes 18 on the next spline 16. As an example, after a voltage is applied sequentially to the first electrodes 18a on each spline 16, a voltage may be applied sequentially to the second splines 16b on each spline 16, and finally a voltage may be applied sequentially to the third splines 16c on each spline 16.

[0041] Moreover, the order of power supply to the first electrode 18a to the third electrode 18c on each spline 16 is not limited. The order of power supply to the first electrode 18a to the third electrode 18c may be different for each spline 16. The order of power supply to the first spline 16a to the sixth spline 16f is also not limited. Furthermore, some splines 16 may be excluded from the power supply target. Furthermore, the voltage may be applied to the same electrode 18 several times in succession to each electrode 18 in order. Furthermore, the electrodes 18 may be divided into a plurality of electrode groups less than the number of the electrodes 18, and the voltage may be applied to each electrode group sequentially. When two or more electrodes 18 belong to an electrode group, when a voltage is applied to the electrode group, the voltage is applied to each electrode 18 simultaneously. The same electrode 18 may be assigned to two or more different electrode groups.

[0042] Furthermore, there is no limitation on the shape or number of the spline 16 and the electrode 18. There may be only one electrode 18. Furthermore, the catheter 4 may not have the spline 16 at the tip of the shaft 10, and the electrode 18 may be disposed on the shaft 10.

[0043] The configurations of the catheter 4 and the power supply device 8 can be changed as appropriate. For example, the distal end side of the shaft 10 of the catheter 4 may be bent in one direction or in 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 (circuit) 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, built into the computer in advance, or may be installed into the computer from a network or a recording medium.

[0044] The above describes the embodiments of the present disclosure in detail. The above-mentioned embodiments merely show specific examples of implementing the present disclosure. The contents of the embodiments do not limit the technical scope of the present disclosure, and many design changes such as changes, additions, and deletions of components are possible within the scope of the idea of ​​the present disclosure defined in the claims. A new embodiment with a design change has the effects of each of the combined embodiments and modifications. In the above-mentioned embodiments, the contents for which such design changes are possible are emphasized by adding notations such as "in this embodiment" and "in this embodiment", but design changes are permitted even in contents without such notations. Any combination of components included in each embodiment is also valid as an aspect of the present disclosure. The hatching on the cross section of the drawing does not limit the material of the object to which the hatching is added.

[0045] The embodiment may be specified by the items described below. [1st item] a power supply (26) electrically connected to the catheter (4) having the electrodes (18) and configured to apply a voltage to the electrodes (18) to generate a biphasic pulse; and a control unit (28) that controls the power supply unit (26) to generate a first pulse set (P1) in which a positive voltage phase pulse (PVP) and a negative voltage phase pulse (NVP) in a biphasic pulse (BP) are successive with a predetermined first interval (A1) therebetween, followed by a second pulse set (P1) in which the positive voltage phase pulse (PVP) and the negative voltage phase pulse (NVP) are successive with a second interval (A2) different from the first interval (A1). Power supply (8). [Second item] The first interval (A1) and the second interval (A2) are at least twice as long as the other interval. The power supply device (8) as described in item 1. [3rd item] a catheter (4) having an electrode (18); The power supply device (8) of the first or second item, Ablation system (1). [Explanation of symbols]

[0046] 1 ablation system, 4 catheter, 8 power supply, 18 electrode, 26 power supply unit, 28 control unit, A1 first interval, A2 second interval, BP biphasic pulse, NVP negative voltage phase pulse, PVP positive voltage phase pulse, P1 first pulse set, P2 second pulse set.

Claims

1. a power supply electrically connected to the catheter having electrodes for applying a voltage to the electrodes to generate a biphasic pulse; and a control unit that controls the power supply unit to generate a first pulse set in which a positive voltage phase pulse and a negative voltage phase pulse in the biphasic pulse are successive with a predetermined first interval therebetween, followed by a second pulse set in which the positive voltage phase pulse and the negative voltage phase pulse are successive with a second interval different from the first interval. power supply.

2. The first interval and the second interval are at least twice as long as the other interval.

2. The power supply device of claim 1.

3. a catheter having an electrode; The power supply device according to claim 1 or 2, Ablation system.

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