Power supply device and ablation system

Abstract

This power supply device comprises: a power supply unit that supplies, between two electrodes, a power Pout for ablation; and a control unit that controls the operation of supplying the power Pout in the power supply unit. The control unit increases, in a continuous or stepwise manner, the power Pout supplied between the two electrodes, and if an impedance Z between the two electrodes has risen, the control unit controls the supply operation so as to decrease the supplied power Pout before reaching a break state and then once again increase the supplied power thereof in a continuous or stepwise manner.

Description

Power Supply and Ablation System

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

[0002] Patients suffering from heart failure, pulmonary hypertension, etc., may experience elevated atrial blood pressure. Shunt surgery, which creates a shunt (a through-hole) in the atrial septum to provide an escape route for the atrial pressure, is known as a treatment for suppressing this elevated atrial pressure. In shunt surgery, the periphery of the through-hole may be ablated (cauterized) using an ablation catheter with an electrode at its tip so that the through-hole is maintained for a predetermined period of time (see, for example, Patent Document 1).

[0003] JP 2017-60825 A

[0004] In ablation techniques, it is naturally required to ablate body tissue reliably.

[0005] The present disclosure has been made in light of these circumstances, and its purpose is to provide a technique for increasing the reliability with which body tissue is ablated in an ablation procedure.

[0006] One aspect of the present disclosure is a power supply device. The power supply device includes a power supply unit that supplies power for ablation between two electrodes and a control unit that controls the power supply operation of the power supply unit. The control unit controls the power supply operation so that the power supplied between the two electrodes is increased continuously or in stages, and when impedance between the two electrodes increases, the power supply is reduced before a break state is reached and then increased continuously or in stages again.

[0007] Another aspect of the present disclosure is an ablation system comprising a plurality of electrodes, some of which are disposed in a catheter and the remaining electrodes, in whole or in part, are disposed in the catheter or a return electrode, and a power supply device according to the above aspect.

[0008] 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.

[0009] According to the present disclosure, it is possible to increase the reliability of ablation of body tissue during ablation procedures.

[0010] It is a schematic diagram of an ablation system according to an embodiment. It is a plan view of a catheter. It is an enlarged cross-sectional view of the distal end side of the catheter. It is an enlarged cross-sectional view of the distal end side of the catheter. It is a diagram showing changes in supplied power and impedance over time.

[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, 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.

[0012] FIG. 1 is a schematic diagram of an ablation system 100 according to an embodiment. In FIG. 1, some of the components of the ablation system 100 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, or 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. Also, FIG. 1 illustrates only a portion of a catheter 1.

[0013] The ablation system 100 is a system for ablation of a treatment site 102 of a patient. The treatment site 102 is, for example, the atrial septum. The treatment site 102 may also be a blood vessel wall or the like. The ablation system 100 includes a catheter 1, a return electrode 104, and a power supply unit 106. The distal end of the catheter 1 is inserted into the treatment site 102 during ablation. The catheter 1 is also electrically connected to the power supply unit 106. Power for ablation is supplied to the electrode 46 of the catheter 1 by the power supply unit 106. The structure of the catheter 1 will be described in detail later.

[0014] The return electrode 104 is attached to the patient's body surface during ablation. The return electrode 104 is electrically connected to a power supply 106. The power supply 106 supplies power for ablation to the electrode 46 of the return electrode 104. In the following, the power supplied between the two electrodes 46 is referred to as a supply power P ｏｕｔ It should be noted that if the catheter 1 has multiple electrodes 46 and power is supplied between the multiple electrodes 46, the return electrode plate 104 may be omitted. In other words, some of the multiple electrodes 46 to which power is supplied from the power supply unit 106 are disposed in the catheter 1, and all or some of the remaining electrodes 46 are disposed in the catheter 1 or the return electrode plate 104. In other words, all of the multiple electrodes 46 may be disposed in the catheter 1, or they may be distributed between the catheter 1 and the return electrode plate 104. Even when electrodes 46 are disposed in both the catheter 1 and the return electrode plate 104, multiple electrodes 46 may be disposed in the catheter 1.

[0015] The power supply device 106 includes an input unit 108, a power supply unit 110, a control unit 112, and a display unit 114. The input unit 108 is configured with, for example, a dial, a button, a touch panel, etc., and is operated by the operator of the ablation system 100. The operator can input various setting values ​​and signals instructing operations to the power supply device 106 via the input unit 108. 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 106. Signals indicating the setting values, etc., are sent from the input unit 108 to the control unit 112.

[0016] The power supply unit 110 supplies power between the two electrodes 46 for ablation of the treatment site 102 in accordance with a control signal CTL sent from the control unit 112. ｏｕｔ is, for example, radio frequency (RF) power. The two electrodes 46 may be composed of an electrode 46 of the catheter 1 and an electrode 46 of the return electrode 104, or may be composed of multiple electrodes 46 of the catheter 1. The power supply unit 110 is composed of a predetermined power supply circuit, for example, a switching regulator. The power supply unit 110 also sends information about the impedance Z between the two electrodes 46 to the control unit 112. The information about the impedance Z may be the value of the impedance Z itself, or may be information required to calculate the impedance Z, such as a current value or a voltage value. When the value of the impedance Z itself is sent to the control unit 112, the power supply unit 110 calculates the impedance Z. When information required to calculate the impedance Z is sent to the control unit 112, the control unit 112 calculates the impedance Z.

[0017] The control unit 112 controls the overall operation of the power supply device 106 and executes predetermined arithmetic processing. The control unit 112 is configured, for example, by a microcomputer. The control unit 112 controls the power supply operation of the power supply unit 110 by sending a control signal CTL generated in accordance with the impedance Z, etc., to the power supply unit 110. The control operation of the control unit 112 will be described in detail later. The display unit 114 displays various types of information to the outside. The display unit 114 is configured, for example, by a liquid crystal display, a CRT display, an organic EL display, etc.

[0018] Next, the structure of the catheter 1 will be described. Figure 2 is a plan view of the catheter 1. An example of the catheter 1 includes a catheter shaft 2, a balloon 4, and a handle 6. The catheter shaft 2 is a long, flexible tubular member. The length of the catheter shaft 2 is, for example, 600 mm to 1800 mm. The balloon 4 is provided on the distal end side of the catheter shaft 2. Figure 1 shows the balloon 4 in an expanded state. The handle 6 is provided on the proximal end side of the catheter shaft 2. The catheter shaft 2 is inserted into the body from the distal end side. This causes the balloon 4 to be delivered into the body. The handle 6 is positioned outside the body and operated by the practitioner.

[0019] Figures 3 and 4 are enlarged cross-sectional views of the distal end of the catheter 1. Figures 3 and 4 show the balloon 4 in an inflated state. The catheter shaft 2 has an outer shaft 8 and an inner shaft 10. The outer shaft 8 and the inner shaft 10 are made of a known flexible material, such as a resin, such as polyolefin or polyamide. The outer shaft 8 is tubular, and the inner shaft 10 is housed therein. The inner shaft 10 is housed in the outer shaft 8 in a state in which it can be displaced relative to the outer shaft 8 in the axial direction of the outer shaft 8.

[0020] The outer shaft 8 of this embodiment has a main lumen 12 extending in a region overlapping with the central axis of the outer shaft 8, and multiple sub-lumens arranged around the main lumen 12. Some of the multiple sub-lumens form a supply lumen 14a, others form a discharge lumen 14b, and still others form a lead wire lumen 14c. The main lumen 12 and each sub-lumen extend from the distal end to the proximal end of the outer shaft 8.

[0021] The inner shaft 10 is housed in the main lumen 12. The distal end of the inner shaft 10 protrudes from the outer shaft 8. A distal tip 16 is fitted over this distal end. The distal tip 16 is made of a known resin material, similar to the catheter shaft 2. The distal tip 16 and the inner shaft 10 are joined to each other, for example, by fusion. A ring-shaped connecting member 18 is fitted into a portion of the outer circumferential surface of the distal tip 16. The connecting member 18 is made of a conductive material such as metal.

[0022] The inner circumferential surface of the distal tip 16 is provided with a groove 16a extending from the base end of the distal tip 16 toward the distal end. The distal tip 16 is also provided with a conductor through-hole 16b extending from the tip of the groove 16a toward the connecting member 18. The catheter 1 is equipped with a conductor 20 extending from the base end of the catheter shaft 2 toward the distal end. The conductor 20 passes through the conductor lumen 14c from the base end of the catheter shaft 2 to the distal tip 16. After reaching the distal tip 16, the conductor 20 passes through the groove 16a and the conductor through-hole 16b and is electrically connected to the connecting member 18. The connecting member 18 and the conductor 20 are joined to each other, for example, by welding. The base end of the conductor 20 is connected to the power supply 110 via the handle 6.

[0023] The inner shaft 10 of this embodiment has a wire lumen 22. The distal tip 16 has a wire through-hole 16c at a position overlapping the wire lumen 22 when viewed in the axial direction of the catheter shaft 2. A guidewire (not shown) is passed through the wire lumen 22 and the wire through-hole 16c.

[0024] The balloon 4 can be inflated by a fluid supplied from the proximal end of the catheter shaft 2. The fluid is, for example, saline. The balloon 4 is made of a known flexible material, including resins such as polyolefin and polyamide. The balloon 4 has a dumbbell shape, with a central portion in the axial direction of the catheter shaft 2 depressed radially over the entire area around the axis of the catheter shaft 2.

[0025] The proximal end side of the balloon 4 encases the outer peripheral surface of the outer shaft 8 in a region adjacent to the balloon 4. The distal end side of the balloon 4 encases the outer peripheral surface of the distal tip 16 on the proximal side of the connecting member 18. The balloon 4 is joined to both the outer shaft 8 and the distal tip 16 by, for example, fusion bonding. The balloon 4 also has a through-hole (not shown). The through-hole connects the inside and outside of the balloon 4 and is a hole for releasing fluid from the balloon 4 to the outside. This through-hole functions as an irrigation mechanism.

[0026] The supply lumen 14a and discharge lumen 14b of the outer shaft 8 are connected to the inside of the balloon 4. The supply lumen 14a is a lumen that allows fluid to flow into the balloon 4. The opening at the tip of the supply lumen 14a is located inside the balloon 4. The base end side of the supply lumen 14a is connected to an external fluid supply / discharge device (not shown) via the handle 6. Fluid sent from the fluid supply / discharge device passes through the supply lumen 14a and is discharged into the balloon 4. This allows the balloon 4 to expand.

[0027] The discharge lumen 14b is a lumen that discharges gas from within the balloon 4. The opening at the tip of the discharge lumen 14b is disposed within the balloon 4. The base end of the discharge lumen 14b is connected to the outside via the handle 6. For example, the discharge lumen 14b is used during an air removal process prior to use of the catheter 1. That is, fluid is supplied from a fluid supply / discharge device into the balloon 4 via the supply lumen 14a. The fluid supplied into the balloon 4 flows into the discharge lumen 14b together with the gas within the balloon 4, and is discharged to the outside via the discharge lumen 14b. When the balloon 4 is deflated during use of the catheter 1, the fluid is discharged from the balloon 4 via the supply lumen 14a.

[0028] The catheter 1 includes an electrode 46 disposed on the surface of the balloon 4. As an example, the electrode 46 is formed of a thin metal film laminated on the surface of the balloon 4. The electrode 46 extends from the connecting member 18 to the constricted portion of the balloon 4. The distal end of the electrode 46 on the catheter shaft 2 is connected to the connecting member 18. This electrically connects the lead wire 20 and the electrode 46 via the connecting member 18. In this embodiment, the electrode 46 has a cylindrical distal end, with multiple strip-shaped portions extending radially from the proximal end of the cylindrical portion. The electrode 46 is covered with an insulating coating (not shown) except for the portion that overlaps with the constricted portion of the balloon 4. The peripheral edge of the shunt fits into the constricted portion of the balloon 4. As a result, the electrode 46 exposed at the constricted portion abuts the peripheral edge of the shunt. In this state, power is supplied to each electrode 46 on the catheter 1 and the return electrode 104, thereby ablating the peripheral edge of the shunt.

[0029] The structure of the catheter 1 is not limited to the above. For example, the catheter 1 may have a basket structure equipped with a plurality of splines instead of the balloon 4. Each spline is a flexible linear body extending in the axial direction of the catheter shaft 2 and is arranged at intervals around the axis of the catheter shaft 2. An electrode 46 is provided on each spline. Each spline is fixed at its base end to the outer shaft 8 and at its tip end to the inner shaft 10. By relative displacement of the outer shaft 8 and the inner shaft 10, each spline can be switched between a straight state and a curved state, i.e., between a folded state and an unfolded state.

[0030] Next, the power supply control executed by the power supply device 106 will be described. ｏｕｔ 5 is a diagram showing the change over time of the supply power P ｏｕｔ The values ​​of the impedance Z and the time are merely examples.

[0031] The contact state between the electrode 46 disposed at the tip of the catheter 1 and the body tissue may not be maintained stably. As a result, the contact area between the electrode 46 and the body tissue may change during ablation. In addition, the thickness and shape of the body tissue with which the electrode 46 comes into contact generally vary from patient to patient. As a result, the contact angle of the electrode 46 with the body tissue varies from patient to patient, and the contact area between the electrode 46 and the body tissue is not always the same. In addition, the conductivity of blood may also vary from patient to patient. The higher the blood conductivity, the smaller the amount of current flowing through the body tissue.

[0032] Due to such variations and differences in ablation conditions, the amount of current flowing through the tissue may vary during ablation and may differ from patient to patient. When the amount of current flowing through the tissue changes, the resistive heat generated within the tissue changes. Therefore, the supplied power P ｏｕｔ When ablation is performed while the device is fixed, reliable ablation of body tissue can be difficult.

[0033] That is, under the ablation conditions where current easily flows through the body tissue, the power P supplied between the two electrodes is ｏｕｔ may become excessive. In this case, the moisture on the surface of the body tissue evaporates and scorches, causing a sudden increase in impedance Z. The state in which impedance Z suddenly increases is called a break state, and is an indicator of whether the body tissue will fall into an excessively heated state. When the body tissue falls into a break state, it becomes difficult for current to flow within the body tissue. As a result, sufficient resistance heat is not generated within the body tissue, making it difficult to ablate the body tissue. Furthermore, if blood is present around the body tissue, the blood is more likely to coagulate and form a thrombus.

[0034] On the other hand, under ablation conditions where current is difficult to flow through the body tissue, the power P supplied between the two electrodes ｏｕｔ In this case, the current flowing through the tissue is so small that not enough resistive heat is generated, making it difficult to ablate the tissue.

[0035] In response to this, the power supply device 106 of this embodiment executes the power supply control described below. That is, the control unit 112 first controls the power supply P ｏｕｔIn other words, the control unit 112 increases the power P supplied between the two electrodes. ｏｕｔ Then, when the impedance Z between the two electrodes increases, the supply power P ｏｕｔ After that, the control unit 112 reduces the supply power P ｏｕｔ The control unit 112 gradually increases the supplied power P ｏｕｔ The period from the start to the end of the increase in power P is defined as one cycle, and multiple cycles are repeated during one ablation procedure. ｏｕｔ is changed periodically.

[0036] More specifically, the control unit 112 performs the first cycle C １ At a predetermined first starting power P ｓ１ Power supply P ｏｕｔ The first starting power P ｓ１ is, for example, about 10 W. ｏｕｔ The rate of increase when gradually increasing is, for example, 10 W / s or less, preferably 1 W / s or less. Normally, the impedance Z gradually decreases from the start of power supply, and at a certain timing, the inflection point Z ｉ When the control unit 112 detects that the impedance Z has changed from a decrease to an increase, it controls the supply power P ｏｕｔ This stops the gradual increase of the first cycle C １ Then, the supply power P ｏｕｔ Reduce the second cycle C ２ Start.

[0037] nth cycle C ｎ (n is a natural number equal to or greater than 1), the minimum supply power P ｏｕｔ is output. ｎ The last part of the cycle is the maximum power supply P ｏｕｔ is output.

[0038] For example, the control unit 112 determines whether the inflection point Z ｉThe increase in impedance Z from the predetermined threshold value ΔZ ｔｈ When it reaches the first cycle C １ The threshold value ΔZ ｔｈ is the inflection point Z ｉ From the threshold value ΔZ ｔｈ The impedance Z that has risen by this amount is the break impedance Z ｂｋ That is, the "break state" in the present disclosure is defined as a state in which the impedance value Z is set to be lower than the break impedance Z ｂｋ This means that the break impedance Z ｂｋ At least the first cycle C １ In the first starting power P ｓ１ The reference impedance Z measured when ｓｔ Therefore, as an example, the control unit 112 determines whether the impedance Z is higher than the reference impedance Z ｓｔ When the value exceeds this, it is determined that the break state has occurred.

[0039] The control unit 112 calculates the reference impedance Z ｓｔ and inflection point Z ｉ and the first cycle C １ Then, the threshold value ΔZ can be calculated from each of the calculated values. ｔｈ For example, a threshold value ΔZ ｔｈ is the inflection point Z ｉ From the threshold value ΔZ ｔｈ The impedance Z that has risen by this amount is the reference impedance Z ｓｔ It is set as follows:

[0040] In addition, the control unit 112 １ Then, after a predetermined time T has elapsed, the first cycle C １ The power supply P at the end of ｏｕｔ The second starting power P is reduced by a predetermined amount ΔP from ｓ２ By supplying the second cycle C ２ As an example, the control unit 112 starts the second start power P ｓ２ The first starting power Pｓ１ Set it to a larger value.

[0041] The control unit 112 performs the second cycle C ２ The second starting power P ｓ２ Power supply P ｏｕｔ When the impedance Z changes from a decrease to an increase, the control unit 112 increases the threshold value ΔZ ｔｈ When it reaches the second cycle C ２ Then, after a predetermined time T has elapsed, the second cycle C ２ The power supply P at the end of ｏｕｔ Smaller supply power P ｏｕｔ The third cycle C ３ The control unit 112 of this embodiment starts the third cycle C ３ After that, the second start power P ｓ２ That is, the control unit 112 starts each cycle with ２ The power supply P at the start of ｏｕｔ The first cycle C １ The power supply P at the start of ｏｕｔ , that is, the first starting power P ｓ１ After that, the same control is repeated until the fourth cycle C ４ ~nth Cycle C ｎ The above steps are performed until one ablation procedure is completed.

[0042] In the above-described power supply control, the following situation may occur. That is, the output voltage of the power supply unit 110 generally has an upper limit. Therefore, in a situation where the impedance Z is high, the power actually supplied (hereinafter referred to as actual supply power as appropriate) may plateau and not rise to the power that is originally intended to be supplied (hereinafter referred to as set supply power as appropriate). In other words, the actual supply power may deviate from the set supply power. When the actual supply power plateaus, the voltage has reached the upper limit, and the actual supply power is at its maximum.

[0043] The control unit 112 determines the supply power P at the start of the next cycle based on the set supply power. ｏｕｔ When determining the supply power P ｏｕｔis the supply power P determined based on the actual supply power that is in a peak state. ｏｕｔ Therefore, if the actual power supply reaches a peak, the impedance Z becomes higher than the threshold value ΔZ ｔｈ When it reaches, the power supply P ｏｕｔ is the actual power supply when the power is at a plateau, that is, the power supply when signs of a breakdown are observed. ｏｕｔ If this happens, signs of a break state may be observed within a short time in the next cycle, and sufficient ablation may not be performed.

[0044] Therefore, the control unit 112 repeatedly acquires information about the actual power supply from the power supply unit 110 and calculates the supply power P ｏｕｔ When it is detected that the actual supply power has reached its peak while the gradual increase control of the power supply is being performed, the control unit 100 ends the cycle being executed regardless of the impedance Z. Then, the control unit 100 ends the cycle by decreasing the actual supply power by a predetermined amount ΔP. ｏｕｔ Start the next cycle.

[0045] The information regarding the actual supply power may be the actual supply power value itself, or may be information required to calculate the actual supply power, such as a current value or a voltage value. In this disclosure, "peaking" means that the actual supply power remains constant for a predetermined period of time. The predetermined period of time can be set appropriately based on the designer's empirical knowledge or experiments or simulations performed by the designer. Furthermore, the predetermined amount ΔP used to calculate the start power for the next cycle may be different between when the next cycle is started in response to an increase in impedance Z and when the next cycle is started in response to a peaking state of the actual supply power.

[0046] As described above, the control unit 112 of this embodiment controls the supply power P ｏｕｔ is increased continuously or stepwise, and when a slight increase in impedance Z corresponding to the cauterization state of the body tissue is detected, the supply power P ｏｕｔ The increase in the power supply P ｏｕｔ Smaller supply power P ｏｕｔThe current is then increased continuously or stepwise from the initial value. This allows a sufficient amount of current to be applied to the tissue under various ablation conditions while avoiding excessive tissue heating. This increases the reliability of tissue ablation. It also reduces thrombus formation.

[0047] In particular, the power supply unit 110 of this embodiment supplies power to the electrodes 46 arranged on the catheter 1. The position and posture of the electrodes 46 arranged on the catheter 1 tend to change easily relative to the body tissue. For this reason, the supply power P ｏｕｔ When ablation is performed with the electrode 46 fixed, the amount of current flowing through the body tissue is likely to fluctuate. Therefore, when the electrode 46 is disposed on the catheter 1, the power supply control executed by the control unit 112 can function more effectively.

[0048] In addition, the control unit 112 performs the second cycle C ２ The power supply P at the start of ｏｕｔ The first cycle C １ First start power P ｓ１ Larger second starting power P ｓ２ As a result, the first cycle C １ Then, the power supply P ｏｕｔ By widening the range of change of the power supply P ｏｕｔ The range of impedance Z and the inflection point Z ｉ The supply power P ｏｕｔ It is possible to grasp the above more reliably. ２ Hereafter, the supply power P ｏｕｔ By narrowing the range of change in the supply of heat to a band with a high supply of heat, it is possible to avoid or shorten the situation in which it is difficult to generate resistance heat in the body tissue that is effective for ablation. This increases the reliability of ablation of the body tissue. It also makes it easier to shorten the time required for ablation surgery.

[0049] In this embodiment, the second cycle C ２ The power supply P at the start of ｏｕｔ The second starting power P ｓ２This simplifies the control. Note that the present invention is not limited to this configuration. For example, the control unit 112 may fix the supplied power P ｏｕｔ The supply power P is lower by a predetermined amount ΔP from ｏｕｔ The next cycle (i.e., the n+1th cycle) may be started at the second cycle C ２ The power supply P at the start of ｏｕｔ The final power supply P of the previous cycle ｏｕｔ This can improve responsiveness to changes in ablation conditions, thereby increasing the reliability of ablation of body tissue.

[0050] In addition, the control unit 112 controls the supply power P ｏｕｔ If the actual supplied power reaches a plateau during the execution of the gradual increase control, the next cycle is started with a supplied power that is lower by a predetermined amount ΔP than the actual supplied power, regardless of the impedance Z. This can further increase the reliability of ablation of body tissue.

[0051] Furthermore, the control unit 112 of this embodiment stops the supply of power for a predetermined time T from the end of the previous cycle, and then starts the next cycle. In this way, when an interval is provided between cycles, the blood around the ablation site is replaced with blood of lower temperature during the interval. This makes it possible to suppress the formation of thrombus due to ablation. Also, during the interval, water moves from the body tissue around the ablation site to the ablation site. Therefore, in the next cycle, the impedance Z reaches the inflection point Z ｉ This can extend the time until the ablation is completed, thereby increasing the reliability of the ablation.

[0052] The control unit 112 may continue to supply power without providing an interval between cycles. In this case, however, the supply power P ｏｕｔ The first starting power P ｓ１ At least the second start power P ｓ２It is preferable to make the power supply smaller than the predetermined value. This makes it possible to provide a time period in the early stage of the next cycle in which power that is too low for ablation is supplied. This time period can have the same effect as an interval. In this disclosure, unless otherwise specified, "reducing the supplied power before entering a break state and then increasing it again continuously or stepwise" includes a case in which power supply is temporarily stopped between the end of the previous cycle and the start of the next cycle, and a case in which power supply is continued between the end of the previous cycle and the start of the next cycle.

[0053] In this embodiment, the inflection point Z ｉ Each cycle is terminated by measuring the increase in impedance Z from the first cycle C. This makes it possible to improve responsiveness to changes in the ablation conditions and increase the reliability of ablation of the body tissue. １ Once the impedance Z at the end is determined, the second cycle C ２ Thereafter, each cycle may be ended with the same impedance Z. This simplifies the control.

[0054] First start power P ｓ１ , supply power P ｏｕｔ Rise rate, break impedance Z ｂｋ (For example, the reference impedance Z ｓｔ (how much larger than the predetermined time T, the predetermined amount ΔP, the second start power P ｓ２ The number of cycles in one ablation procedure can be set appropriately based on the designer's empirical knowledge or experiments or simulations.

[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, 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 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] The embodiments may be specified by the following items: [Item 1] Ablation power (P ｏｕｔ a power supply unit (110) for supplying a power (P) between the two electrodes (46); ｏｕｔ and a control unit (112) for controlling the supply of power (P) between the two electrodes (46). ｏｕｔ ) is increased continuously or stepwise, and when the impedance (Z) between the two electrodes (46) increases, the supply power (P ｏｕｔ The power supply device (106) controls the supply operation so that the supply power (P) is reduced and then increased again continuously or stepwise. ｏｕｔ When the period from the start to the end of the increase in the voltage (C) is defined as one cycle, the control unit (112) ２ ) and the supply power (P ｏｕｔ , P ｓ２ ) in the first cycle (C １ ) supply power (P ｏｕｔ , P ｓ１ Item 3: The power supply device (106) according to item 1, wherein the supply power (P ｏｕｔWhen the period from the start to the end of the increase in the power supply voltage (P) is considered as one cycle, the power supply voltage (P) at the end of the previous cycle is ｏｕｔ ) by a predetermined amount (ΔP) ｏｕｔ Item 4: The power supply device (106) according to item 1 or 2, wherein the next cycle is started with a supply power (P ｏｕｔ When the period from the start to the end of the increase in the supply power (P ｏｕｔ When the actual supply power actually supplied between the two electrodes (46) reaches a ceiling in a situation where the supply operation is controlled to increase the impedance (Z), the supply power (P) is lower than the actual supply power by a predetermined amount (ΔP) set in advance. ｏｕｔ ) to start a next cycle. [Item 5] The power supply unit (110) supplies power (P ｏｕｔ Item 6: An ablation system (100) comprising: a plurality of electrodes (46), some of which are disposed on the catheter (1) and the whole or part of which are disposed on the catheter (1) or a return electrode (104); and the power supply device (106) according to any of items 1 to 5.

[0057] The present disclosure may be utilized in power supply devices and ablation systems.

[0058] 1 catheter, 46 electrode, 100 ablation system, 104 return electrode, 106 power supply device, 110 power supply unit, 112 control unit, P ｏｕｔ Z the supply power, Z the impedance.

Claims

1. A power supply device comprising: a power supply unit that supplies power for ablation between two electrodes; and a control unit that controls the power supply operation of the power supply unit, wherein the control unit increases the power supplied between the two electrodes continuously or in stages, and, when the impedance between the two electrodes increases, controls the supply operation so that the power supplied is reduced before a break state is reached and then is increased continuously or in stages again.

2. The power supply device according to claim 1, wherein, when the period from the start to the end of the increase in the supply power is defined as one cycle, the control unit makes the supply power at the start of a second cycle or later greater than the supply power at the start of a first cycle.

3. A power supply device according to claim 1 or 2, wherein, when the period from the start to the end of the increase in the supply power is defined as one cycle, the next cycle is started at a supply power that is lower by a predetermined amount than the supply power at the end of the previous cycle.

4. A power supply device as described in claim 1 or 2, wherein, when one cycle is defined as the period from the start to the end of the increase in the supply power, if the actual supply power actually supplied between the two electrodes reaches its peak while the control unit is controlling the supply operation to increase the supply power, the control unit starts the next cycle at the supply power that is lower than the actual supply power by a predetermined amount regardless of the impedance.

5. The power supply device according to claim 1 or 2, wherein the power supply unit supplies power to an electrode disposed in a catheter.

6. An ablation system comprising: a plurality of electrodes, some of which are disposed in a catheter, and the remaining electrodes, in whole or in part, are disposed in the catheter or a return electrode; and the power supply device according to claim 1 or 2.

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