Intracardiac defibrillation catheter system and method for controlling intracardiac defibrillation catheter system

Abstract

This intracardiac defibrillation catheter system (1) includes: a power supply (13) that applies a voltage to an electrode part (5) of a catheter (2); a voltage application permission signal generation unit (21) connected to the power supply (13); first switches (31A to 31D) connected to the power supply (13); and second switches (32A to 32D) disposed closer to the power supply (13) than the first switches (31A to 31D), wherein control is carried out such that after generation of a permission signal, the first switches (31A to 31D) are turned from ON to OFF, then the second switches (32A to 32D) are turned from OFF to ON, and then a voltage is applied to the electrode part (5).

Description

Intracardiac defibrillation catheter system and method for controlling the intracardiac defibrillation catheter system

[0001] The present invention relates to an intracardiac defibrillation catheter system used for performing defibrillation in a cardiac chamber, and a control method thereof.

[0002] In the treatment of arrhythmias such as atrial fibrillation and ventricular fibrillation, defibrillation is performed to restore the heart's rhythm to normal by applying electrical stimulation. Devices used for defibrillation include automated external defibrillators (AEDs), implantable cardioverter defibrillators (ICDs), defibrillation paddles, and intracardiac defibrillation catheter systems. An intracardiac defibrillation catheter system is a device that directly applies electrical stimulation to the heart through electrodes attached to the surface of the catheter. An intracardiac defibrillation catheter system can also measure intracardiac potentials using the electrodes. Defibrillation catheter systems are advantageous in that they can use lower-energy voltage waveforms than automated external defibrillators, thereby reducing the burden on patients and allowing them to be used during catheterization tests and ablation procedures for arrhythmias.

[0003] In the treatment of atrial fibrillation, it is necessary to apply a voltage to the heart during the absolute refractory period so that the ventricular muscle does not react. If a stimulus is applied to the heart outside the absolute refractory period, the ventricular muscle may react, leading to the risk of transitioning to ventricular fibrillation. For this reason, defibrillation catheter systems apply a voltage in synchronization with the R wave. Patent Documents 1 to 5 disclose examples of defibrillation catheter systems. For example, Patent Document 1 discloses that the first ON / OFF switch is turned ON and the second ON / OFF switch is turned OFF during cardiac potential measurement, that the first ON / OFF switch is turned OFF and the second ON / OFF switch is turned ON during defibrillation, that an input from an energy application preparation switch 744 receives a control signal from an arithmetic processing unit 75, causing the first ON / OFF switch to remain ON and the second ON / OFF switch to switch from OFF to ON, and that an input from an energy application execution switch 745 receives a control signal from the arithmetic processing unit 75, causing the second ON / OFF switch to remain ON and the first ON / OFF switch to switch from ON to OFF. Thus, in the system described in Patent Document 1, when the defibrillation application button is pressed, the power supply side switch is already maintained ON, and the electrocardiograph side switch is turned OFF after the defibrillation application button is pressed. Patent Document 1 also describes that electrocardiogram signals can be measured from the catheter even when both the power supply switch and the electrocardiograph switch are on.

[0004] International Publication No. 2022 / 195644 International Publication No. 2023 / 026346 International Publication No. 2021 / 191988 Japanese Patent Application Laid-Open No. 2017-176349 Special Publication No. 2004-534622

[0005] In the systems described in Patent Documents 1 to 5, when measuring electrocardiographic signals, an electric field is generated due to the parasitic capacitance of the power supply side circuit, which can cause current to flow to the electrode part of the catheter, generating noise, or the electrocardiographic signal from the electrode part of the catheter to flow to the power supply side instead of the electrocardiograph, resulting in insufficient electrocardiographic signals from the electrode part to the electrocardiograph. Therefore, an object of the present invention is to provide an intracardiac defibrillation catheter system and a control method for an intracardiac defibrillation catheter system that can measure electrocardiographic signals while reducing noise while the catheter is connected to an electrocardiograph, regardless of the parasitic capacitance of the power supply side circuit, etc.

[0006] An intracardiac defibrillation catheter system according to an embodiment of the present invention that can solve the above problems is as follows: [1] An intracardiac defibrillation catheter system comprising: a catheter having a longitudinal axis direction, an electrode portion disposed at a distal portion of the catheter, a power source for applying a voltage to the electrode portion, an enable signal generating unit connected to the power source and generating an enable signal for enabling application of a voltage for defibrillation, a first switch connected to the power source, and a second switch connected to the power source and disposed closer to the power source than the first switch, the first switch and the second switch being independent of each other, and the power source being controlled so that the first switch changes from ON to OFF after the enable signal generating unit generates the enable signal, and then the second switch changes from OFF to ON, after which the power source applies a voltage to the electrode portion.

[0007] Furthermore, the intracardiac defibrillation catheter system according to the embodiment is preferably any one of the following [2] to [9]. [2] The intracardiac defibrillation catheter system according to [1], further comprising a first delay unit connected to the second switch and delaying the activation timing of the second switch so that the second switch changes from OFF to ON after a first predetermined time has elapsed after the first switch changes from ON to OFF. [3] The intracardiac defibrillation catheter system according to [2], wherein the first predetermined time is 5 ms or more and 30 ms or less. [4] The intracardiac defibrillation catheter system according to any one of [1] to [3], further comprising a power output control unit disposed in a connection path between the power source and the second switch, the power output control unit having a third switch, and the power source is controlled so that the third switch changes from OFF to ON after the second switch changes from OFF to ON, and then the power source applies a voltage to the electrode unit. [5] The intracardiac defibrillation catheter system according to any one of [1] to [4], wherein an impedance measuring unit is disposed in a connection path between the power supply and the second switch, and wherein the impedance measuring unit starts measuring impedance after the second switch is turned from OFF to ON. [6] The intracardiac defibrillation catheter system according to [5], further comprising: a second delay unit connected to the impedance measuring unit and delaying the operation timing of the impedance measuring unit so that the impedance measurement starts after a second predetermined time has elapsed after the second switch is turned from OFF to ON. [7] The intracardiac defibrillation catheter system according to [6], wherein the second predetermined time is 5 ms or more and 20 ms or less. [8] The intracardiac defibrillation catheter system according to any one of [1] to [7], further comprising: an input unit to which an electrocardiogram signal is input, the input unit being connected to an electrocardiograph; and a detection unit connected to the input unit and detecting an R wave using the electrocardiogram signal input to the input unit. [9] The intracardiac defibrillation catheter system according to any one of [1] to [8], further comprising a first connection part connected to an electrocardiograph, wherein the first switch is disposed closer to the first connection part than the second switch.

[0008] A control method for an intracardiac defibrillation catheter system according to an embodiment of the present invention that can solve the above problems is as follows:

[10] A control method for an intracardiac defibrillation catheter system having: a catheter having a longitudinal axis direction, an electrode portion disposed in a distal portion of the catheter, a power source that applies a voltage to the electrode portion, an enable signal generating unit connected to the power source and generating an enable signal that enables application of a voltage for defibrillation, a first switch connected to the power source, and a second switch connected to the power source and disposed closer to the power source than the first switch, wherein the first switch and the second switch are independent of each other, the control method for an intracardiac defibrillation catheter system comprising: a step of generating the enable signal from the enable signal generating unit; a step of turning the first switch from ON to OFF; a step of turning the second switch from OFF to ON; and a step of the power source applying a voltage to the electrode portion.

[0009] Furthermore, the control method for the intracardiac defibrillation catheter system according to the embodiment is preferably any one of the following

[11] to

[14] .

[0010]

[11] The method for controlling an intracardiac defibrillation catheter system according to

[10] , wherein the intracardiac defibrillation catheter system further includes a first delay unit connected to the second switch and delaying the activation timing of the second switch, and after a step of turning the first switch from ON to OFF, a step of turning the second switch from OFF to ON after a first predetermined time has elapsed due to the first delay unit.

[12] The method for controlling an intracardiac defibrillation catheter system according to

[10] or

[11] , wherein the intracardiac defibrillation catheter system further includes a power supply output control unit arranged in a connection path between the power supply and the second switch, the power supply output control unit having a third switch, and includes a step of turning the third switch from OFF to ON after the step of turning the second switch from OFF to ON, and wherein the power supply applies a voltage to the electrode unit after the third switch is turned ON.

[13] The method for controlling an intracardiac defibrillation catheter system according to any one of

[10] to

[12] , wherein the intracardiac defibrillation catheter system further comprises an impedance measuring unit arranged in a connection path between the power supply and the second switch, and includes a step of measuring impedance by the impedance measuring unit after the second switch is turned from OFF to ON.

[14] The method for controlling an intracardiac defibrillation catheter system according to

[13] , wherein the intracardiac defibrillation catheter system further comprises a second delay unit connected to the impedance measuring unit and delaying the activation timing of the impedance measuring unit, and includes a step of starting the step of measuring impedance by the impedance measuring unit after a second predetermined time has elapsed after the second switch is turned from OFF to ON.

[0011] According to the above-described intracardiac defibrillation catheter system and control method for the intracardiac defibrillation catheter system, the first switch is turned from ON to OFF, and then the second switch is turned from OFF to ON, so that while the catheter is connected to the electrocardiograph, electrocardiographic signals can be measured with reduced noise, regardless of parasitic capacitance of the power supply side circuit, etc. Furthermore, because the second switch is turned from OFF to ON while the first switch is OFF, damage to the electrocardiograph due to a large current flowing from the power supply to the electrocardiograph side can be prevented.

[0012] 1 is a schematic diagram of an intracardiac defibrillation catheter system according to an embodiment of the present invention. 2 is a circuit diagram of an intracardiac defibrillation catheter system according to an embodiment of the present invention. 3 is a circuit diagram showing a state in which a first switch is OFF, a second switch is ON, and a third switch is OFF in the intracardiac defibrillation catheter system shown in FIG. 2. 4 is a circuit diagram showing a state in which a first switch is OFF, a second switch is ON, and a third switch is ON in the intracardiac defibrillation catheter system shown in FIG. 2. 5 is a circuit diagram showing a state in which a first switch is ON, a second switch is OFF, and a third switch is OFF in the intracardiac defibrillation catheter system shown in FIG. 2. 6 is a circuit diagram showing a state in which a first switch is ON, a second switch is OFF, and a third switch is OFF in the intracardiac defibrillation catheter system shown in FIG. 2. 7 is a flowchart showing a control method for an intracardiac defibrillation catheter system according to an embodiment of the present invention. 8 is a flowchart showing a modified example of the control method for the intracardiac defibrillation catheter system shown in FIG. 7. 9 is a flowchart showing another modified example of the control method for the intracardiac defibrillation catheter system shown in FIG. 7.

[0013] The present invention will be described in more detail below based on the following embodiments. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings. In such cases, reference should be made to the specification and other drawings. The dimensions of various components in the drawings may differ from their actual dimensions, as priority is given to helping understand the features of the present invention.

[0014] An intracardiac defibrillation catheter system according to one embodiment of the present invention comprises a catheter having a longitudinal axis, an electrode portion disposed at a distal portion of the catheter, a power source for applying a voltage to the electrode portion, an enable signal generating unit connected to the power source and generating an enable signal for enabling application of a voltage for defibrillation, a first switch connected to the power source, and a second switch connected to the power source and disposed closer to the power source than the first switch, the first switch and the second switch being independent of each other, and being controlled so that the first switch is turned from ON to OFF after the enable signal generating unit generates the enable signal, and then the second switch is turned from OFF to ON, after which the power source applies a voltage to the electrode portion. With the intracardiac defibrillation catheter system, the first switch is turned from ON to OFF, and then the second switch is turned from OFF to ON, so that electrocardiographic signals can be measured with reduced noise while the catheter is connected to an electrocardiograph, regardless of parasitic capacitance or the like of a power supply side circuit. Furthermore, since the second switch is turned from OFF to ON while the first switch is in the OFF state, damage to the electrocardiograph due to a large current flowing from the power supply to the electrocardiograph can be prevented.

[0015] An intracardiac defibrillation catheter system according to one embodiment of the present invention will be described with reference to Figures 1 to 6. Figure 1 is a schematic diagram of an intracardiac defibrillation catheter system according to one embodiment of the present invention. Figure 2 is a circuit diagram of an intracardiac defibrillation catheter system according to one embodiment of the present invention. Figure 3 is a circuit diagram of the intracardiac defibrillation catheter system shown in Figure 2, showing a state in which the first switch is OFF, the second switch is ON, and the third switch is OFF. Figure 4 is a circuit diagram of the intracardiac defibrillation catheter system shown in Figure 2, showing a state in which the first switch is OFF, the second switch is ON, and the third switch is ON. Figure 5 is a circuit diagram of the intracardiac defibrillation catheter system shown in Figure 2, showing a state in which the first switch is ON, the second switch is OFF, and the third switch is OFF. Figure 6 is a circuit diagram of the intracardiac defibrillation catheter system shown in Figure 2, showing a state in which the first switch is ON, the second switch is ON, and the third switch is OFF. Hereinafter, the intracardiac defibrillation catheter system may be simply referred to as a system. System 1 includes catheter 2, electrode unit 5, power supply 13, permission signal generator 21, first switch, and second switch. 1 and 2 illustrate an example in which system 1 includes first switch group 31 including first switches 31A, 31B, 31C, and 31D, and second switch group 32 including second switches 32A, 32B, 32C, and 32D, but as described below, the numbers of first switches and second switches can be set appropriately depending on the number of electrodes.

[0016] The system 1 preferably includes: (i) a catheter 2 having a longitudinal axis and an electrode unit 5 disposed at a distal portion; and (ii) a defibrillation electrical device 10 including a power source 13 for applying a voltage to the electrode unit 5, an enable signal generating unit 21 connected to the power source 13 and generating an enable signal for enabling application of a voltage for defibrillation, a first switch connected to the power source 13, and a second switch connected to the power source 13 and disposed closer to the power source 13 than the first switch. In this case, the first switch and the second switch are independent of each other, and are preferably controlled so that the first switch changes from ON to OFF after the enable signal is generated from the enable signal generating unit 21, and then the second switch changes from OFF to ON, after which the power source 13 applies a voltage to the electrode unit 5. Hereinafter, the defibrillation electrical device 10 may be simply referred to as the electrical device 10.

[0017] As can be seen from FIG. 1 , the catheter 2 has a longitudinal axis direction. The longitudinal axis direction refers to the direction from the proximal side to the distal side of the catheter 2. The proximal side of the catheter 2 refers to the side closer to the user (operator) with respect to the extension direction of the catheter 2, and the distal side refers to the side opposite the proximal side (i.e., the side to be treated). The catheter 2 preferably has a circumferential direction and a radial direction. As shown in FIG. 1 , an electrode unit 5 is disposed in the distal portion of the catheter 2. The electrode unit 5 is preferably composed of two or more electrodes, and is preferably composed of at least one pair of a positive electrode and a negative electrode.

[0018] By inserting the catheter 2 into a cardiac cavity and bringing the electrode unit 5 into contact with the inner surface of an atrium, ventricle, or blood vessel, the electrode unit 5 detects minute voltages generated in association with cardiac pulsation, thereby measuring the intracardiac potential. As will be described later, an electrocardiogram waveform (also referred to as electrocardiogram waveform or electrocardiogram data) can be obtained using an electrocardiograph 50 or the like based on the measured electrocardiogram signal. Therefore, the electrocardiogram signal measured by the electrode unit 5 is preferably input to an input unit 22, which will be described later. The electrocardiogram signal measured by the electrode unit 5 is preferably taken into the electrocardiograph 50.

[0019] The catheter 2 is inserted into a cardiac cavity, the electrode unit 5 is brought into contact with the inner surface of an atrium, a ventricle, or a blood vessel, and a voltage is applied to the electrode unit 5. For example, a voltage can be applied so that a current flows from the positive electrode through the living body to the negative electrode, or from the negative electrode through the living body to the positive electrode.

[0020] The catheter 2 may be a cylindrical resin tube. The resin tube may be manufactured by extrusion molding, for example. The resin tube may have one or more lumens. The catheter 2 may be made of a single layer or multiple layers. A portion of the catheter 2 in the longitudinal or circumferential direction may be made of a single layer, and the other portion may be made of multiple layers.

[0021] Examples of resins that can be used to form the catheter 2 include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, fluorine-based resins, vinyl chloride resins, silicone resins, and natural rubber. These resins can be used alone or in combination of two or more. Among these, polyamide resins, polyester resins, polyurethane resins, polyolefin resins, and fluorine-based resins are preferred.

[0022] The electrode unit 5 preferably includes multiple electrodes. The multiple electrodes are preferably positioned at offset positions along the longitudinal axis of the catheter 2. This allows intracardiac potentials to be measured at various positions. For example, the intracardiac potential between adjacent electrodes can be measured by measuring the potential difference between each electrode. For example, as shown in FIGS. 1 and 2 , the electrode unit 5 may include a first electrode group 6 including a first most distal electrode 6A and a first most proximal electrode 6B, and a second electrode group 7 including a second most distal electrode 7A and a second most proximal electrode 7B. The second electrode group 7 is preferably located more proximal than the first electrode group 6 along the longitudinal axis of the catheter 2. In other words, the distal end of the second most distal electrode 7A, which is located most distal in the second electrode group 7, is preferably located more proximal than the proximal end of the first most proximal electrode 6B, which is located most proximal in the first electrode group 6. Thus, it is preferable that the first electrode group 6 and the second electrode group 7 each include multiple electrodes. This allows voltage to be applied over a wide area of ​​the heart, resulting in efficient defibrillation. The first electrode group 6 is preferably positioned at a location corresponding to the coronary sinus, and the second electrode group 7 is preferably positioned at a location corresponding to the right atrium. In FIG. 1 , the first electrode group 6 includes eight electrodes, and the second electrode group 7 includes eight electrodes.

[0023] The electrode included in the first electrode group 6 may be a positive electrode or a negative electrode. When the electrode included in the first electrode group 6 is a positive electrode, the electrode included in the second electrode group 7 may be a negative electrode. When the electrode included in the first electrode group 6 is a negative electrode, the electrode included in the second electrode group 7 may be a positive electrode.

[0024] It is preferable that DC voltages of different polarities are applied to the multiple electrodes of the electrode unit 5. In particular, it is preferable that DC voltages of different polarities are applied to the electrodes of the first electrode group 6 and the electrodes of the second electrode group 7. Current can be applied from the electrodes of the first electrode group 6 to the electrodes of the second electrode group 7, or in the opposite direction. For example, by applying a biphasic DC voltage, it is possible to eliminate defibrillation with less energy.

[0025] It is preferable that a voltage of the same polarity (positive or negative) be applied to each of the multiple electrodes in the first electrode group 6. It is also preferable that a voltage of the same polarity (negative or positive) be applied to each of the multiple electrodes in the second electrode group 7. For example, when applying a biphasic DC voltage, a current can be passed from the right atrium toward the coronary sinus by applying a negative voltage to the electrodes in the first electrode group 6 and a positive voltage to the electrodes in the second electrode group 7 during the first half of the current application, and a current can be passed from the coronary sinus toward the right atrium by applying a positive voltage to the electrodes in the first electrode group 6 and a negative voltage to the electrodes in the second electrode group 7 during the second half of the current application.

[0026] The number of electrodes in the first electrode group 6 and the number of electrodes in the second electrode group 7 may be different, but are preferably the same. By making these numbers the same, it is possible to easily make the total surface area of ​​the electrodes in the first electrode group 6 and the total surface area of ​​the electrodes in the second electrode group 7 the same. By evenly arranging the same number of electrodes and making the total surface area of ​​the electrodes in the first electrode group 6 and the total surface area of ​​the electrodes in the second electrode group 7 the same, it is possible to improve the accuracy of measuring intracardiac potentials and perform defibrillation efficiently.

[0027] The number of electrodes in the first electrode group 6 and the number of electrodes in the second electrode group 7 are, for example, preferably 6 or more, more preferably 8 or more, and preferably 12 or less, more preferably 10 or less.

[0028] When the first electrode group 6 has multiple electrodes, it is preferable that the separation distance between adjacent electrodes in the first electrode group 6 in the longitudinal axis direction is shorter than the separation distance between the first most proximal electrode 6B of the first electrode group 6 and the second most distal electrode 7A of the second electrode group 7.

[0029] When the second electrode group 7 has multiple electrodes, it is preferable that the separation distance between adjacent electrodes in the second electrode group 7 in the longitudinal axis direction is shorter than the separation distance between the first most proximal electrode 6B of the first electrode group 6 and the second most distal electrode 7A of the second electrode group 7.

[0030] The electrode unit 5 is preferably connected to the electrocardiograph 50. The electrode unit 5 is preferably connected to the electrocardiograph 50 via the defibrillation electrical device 10. One or more electrodes of the first electrode group 6 and one or more electrodes of the second electrode group 7 are preferably connected to the electrocardiograph 50.

[0031] In order to reduce errors in the voltages applied to the multiple electrodes, the system 1 preferably has a wiring connection portion 35 where the wiring of the multiple electrodes is connected to each other. The wiring connection portion 35 may have a first wiring connection portion where the wiring connected to each of the multiple electrodes in the first electrode group 6 is connected to each other. This shorts out the wiring connected to the first electrode group 6. For the same reason, the wiring connection portion 35 may have a second wiring connection portion where the wiring connected to each of the multiple electrodes in the second electrode group 7 is connected to each other.

[0032] The electrode unit 5 may have one or more electrodes located more proximal than the second electrode group 7. Arranging the electrodes in this manner allows intracardiac potentials to be measured over a wider range. For example, in FIG. 1 , the electrode unit 5 has a third electrode group 8 including multiple electrodes located more proximal than the second electrode group 7. In FIG. 1 , the third electrode group 8 has four electrodes. It is preferable that the third electrode group 8 be electrodes dedicated to measuring intracardiac potentials, and it is preferable that no voltage is applied by the third electrode group 8.

[0033] The third electrode group 8 is preferably connected to the electrocardiograph 50. Although Fig. 2 shows only electrodes 8A-8B of the third electrode group 8, it is preferable that the other electrodes are also connected to the electrocardiograph 50. The third electrode group 8 and the electrocardiograph 50 may be connected via a switch element or a resistor, but as shown in Fig. 2, they are preferably connected without a switch element or a resistor. Connecting the third electrode group 8 and the electrocardiograph 50 without a switch element or a resistor allows for accurate measurement of intracardiac potentials.

[0034] The surface areas of the electrodes of the electrode unit 5 may be different from one another, but are preferably the same. By making the surface areas the same, the accuracy of measuring the intracardiac potential can be improved.

[0035] In the electrode unit 5, the widths of the multiple electrodes in the longitudinal direction of the catheter 2 may be different, but are preferably the same. By making the electrode widths the same, the measurement accuracy of the intracardiac potential can be improved. The width of each electrode is preferably, for example, 0.5 mm or more and 5 mm or less.

[0036] In the electrode section 5, the spacing between adjacent electrodes in the longitudinal direction of the catheter 2, i.e., the distance between the distal end of one electrode and the proximal end of the other electrode located distal to the first electrode, is preferably, for example, 1 mm to 10 mm, more preferably 3 mm to 8 mm. Setting the spacing in this manner can improve the accuracy of measuring intracardiac potentials.

[0037] Each electrode of the electrode unit 5 is preferably present in an area covering more than half of the outer circumference of the catheter 2, and more preferably in an area covering the entire outer circumference of the catheter 2. Each electrode of the electrode unit 5 is more preferably ring-shaped. Such an electrode shape increases the contact area with the heart, making it easier to measure intracardiac potentials and apply electrical stimulation.

[0038] The electrodes of the electrode unit 5 preferably contain a conductive material such as platinum or stainless steel, and among conductive materials, they more preferably contain a radiopaque material, and even more preferably contain an X-ray opaque material. Of these, it is preferable that each electrode contains platinum. When the electrodes contain a radiopaque material, the position of the electrodes can be easily determined under radioscopy.

[0039] A lead wire is connected to each electrode of the electrode unit 5. Specifically, one end of the lead wire, which is disposed in the lumen of the resin tube, is joined to the inner surface of the electrode through a side hole provided in the outer surface of the resin tube. The other end of the lead wire is preferably connected to a predetermined connector of the defibrillation electrical device 10, which will be described later.

[0040] A distal tip 3 is preferably provided at the distal end of the catheter 2. The distal tip 3 preferably has a portion whose outer diameter decreases toward the distal end of the distal tip 3. This can improve the ease of insertion of the catheter 2 into the body.

[0041] Examples of materials that can be used to form the distal tip 3 include conductive materials and polymeric materials. In particular, the distal tip 3 can function as an electrode when it is made of a conductive material. The hardness of the distal tip 3 is preferably lower than that of the catheter 2. This allows the distal tip 3 to protect body tissue when it comes into contact with a body cavity.

[0042] A handle 4 is preferably disposed on the proximal side of the catheter 2, which is held by the user when operating the catheter 2. The size of the handle 4 is not particularly limited as long as it is suitable for holding with one hand. The length of the handle 4 is not particularly limited, but is preferably, for example, 5 cm or more and 20 cm or less. The outermost diameter (circular equivalent diameter) of the handle 4 is not particularly limited, but is preferably, for example, 1 cm or more and 5 cm or less. Examples of materials that can be used to form the handle 4 include synthetic resins such as ABS and polycarbonate, and foamed plastics such as polyurethane foam.

[0043] As shown in FIGS. 1 and 2, the system 1 includes a power supply 13 that applies a voltage to the electrode unit 5. The power supply 13 preferably includes a capacitor. The power supply 13 preferably includes a power supply circuit for generating a DC voltage. The power supply circuit may include, for example, a boost circuit that boosts the DC voltage and a capacitor that charges the applied voltage. For example, it is preferable that a charging switch 43, which is preferably provided, be turned on, so that a predetermined applied voltage is applied to the capacitor and the capacitor is charged. In FIG. 2, the power supply 13 is connected to an enable signal generating unit 21, first switches 31A to 31D, and second switches 32A to 32D.

[0044] As shown in Fig. 2, the system 1 preferably has a first connection unit 15 connected to the electrocardiograph 50. The first connection unit 15 is preferably a connection terminal, and is more preferably provided on the defibrillation electrical device 10. The first connection unit 15 may be part of a circuit constituting the control unit 20, an input terminal physically connected to the electrocardiograph 50, or part of a wireless communication device that receives electrocardiographic signals. In Fig. 2, the first switches 31A to 31D are connected to the electrocardiograph 50 via the first connection unit 15.

[0045] The system 1 may further include a connector connected to the electrode unit 5 of the catheter 20. For example, as shown in FIG. 2 , the system 1 may include a second connector 16 connected to the electrode unit 5. The second connector 16 is preferably connected to the electrodes of the first electrode group 6 and the second electrode group 7. The system 1 may also include a third connector 17 connected to the electrocardiograph 50 and a fourth connector 18 connected to the electrodes of the third electrode group 8. The second connector 16, the third connector 17, and the fourth connector 18 are preferably connection terminals. The second connector 16, the third connector 17, and the fourth connector 18 may be part of a circuit constituting the control unit 20. The third connector 17 may be an input terminal physically connected to the electrocardiograph 50, or may be part of a wireless communication device that receives electrocardiographic signals. FIG. 2 shows an example in which the first connection portion 15 and the second connection portion 16 are connected to each other via a conductor, and the third connection portion 17 and the fourth connection portion 18 are connected to each other via a conductor within the defibrillation electrical device 10, but the connection may be made wirelessly and / or by wire.

[0046] As shown in FIG. 2 , the system 1 is connected to the power source 13 and includes an enable signal generator 21 that generates an enable signal to enable application of a voltage for defibrillation. The enable signal is not particularly limited as long as it is a signal related to application of a voltage for defibrillation, and examples thereof include a signal to enable charging of the power source 13, a signal to enable generation of a pulse voltage, a signal to enable voltage application, and a signal to enable switching on or off of each switch element. The enable signal generator 21 may generate at least one of these enable signals. In another embodiment, some of these enable signals may be generated by operation of an operation unit, etc. The enable signal generator 21 may be directly or indirectly connected to the power source 13. The enable signal generator 21 may be provided in the control unit 20, which will be described later.

[0047] In FIG. 2 , the system 1 includes first switches 31A-31D connected to the power source 13 and second switches 32A-32D connected to the power source 13 and located closer to the power source 13 than the first switches 31A-31D. The first and second switches refer to switch elements mounted on an electronic circuit board and are distinguished from operational switches such as pushbutton switches and lever switches that are operated by a user to switch between ON and OFF. By appropriately switching the first and second switches ON and OFF, voltage application and intracardiac potential measurement can be performed by outputting a DC voltage from the power source 13 to each electrode. The phrase "the first and second switches are connected to the power source 13" includes both a case where the first or second switch is connected to the power source 13 by a conductor and a case where the first or second switch is connected to the power source 13 via a conductor or a member other than the conductor. The first switch is preferably located closer to the first connection portion 15 than the second switch. The phrase "the first switch is arranged closer to first connection portion 15" than the second switch means that the first switch is arranged closer to first connection portion 15 than the second switch. Furthermore, the phrase "the second switch is arranged closer to power source 13" than the first switch means that the second switch is arranged closer to power source 13 than the first switch. Here, the first switch and the second switch are independent of each other. Because they are independent of each other, the electrodes in first electrode group 6 and the electrodes in second electrode group 7 can be electrically separated, and each electrode can be controlled independently.

[0048] The first switch and the second switch may be a relay switch or a semiconductor switch. Examples of semiconductor switch elements include an IGBT, a MOSFET, a thyristor, an element using a SiC semiconductor, and an element using a GaN semiconductor.

[0049] As shown in FIG. 2 , the system 1 may include a switching unit 30 including a first switch and a second switch. The switching unit 30 preferably switches between a first mode in which the power supply 13 and the electrode unit 5 are electrically disconnected and a second mode in which the power supply 13 and the electrode unit 5 are electrically connected. The first mode is preferably a cardiac potential measurement mode in which an electrocardiogram signal is measured using the electrode unit 5, and the second mode is preferably a defibrillation mode in which a voltage is applied to the electrode unit 5. The switching unit 30 preferably switches from the first mode to the second mode and from the second mode to the first mode. The switching unit 30 preferably switches the mode based on an electrocardiogram signal input from the input unit 22.

[0050] It is more preferable that the switching unit 30 includes a plurality of first switches and a plurality of second switches. In FIG. 2, the switching unit 30 includes a first switch group 31 having a plurality of first switches 31A-31D and a second switch group 32 having a plurality of second switches 32A-32D. It is preferable that the first switches 31A-31D are connected in parallel with each other. It is also preferable that the second switches 32A-32D are connected in parallel with each other. This allows the plurality of electrodes to be electrically isolated, allowing intracardiac potentials to be measured independently at each electrode. It is preferable that the electrodes of the electrode unit 5 are connected to the power source 13 via the second switch, and the electrodes of the electrode unit 5 are connected to the electrocardiograph 50 via the first switch. 2 , the first electrode group 6 has a first most distal electrode 6A and a first most proximal electrode 6B, and the second electrode group 7 has a second most distal electrode 7A and a second most proximal electrode 7B, and the first most distal electrode 6A, the first most proximal electrode 6B, the second most distal electrode 7A, and the second most proximal electrode 7B are each connected to the electrocardiograph 50. In particular, the first most distal electrode 6A is connected to the power supply 13 via a second switch 32A, the first most proximal electrode 6B is connected to the power supply 13 via a second switch 32B, the second most distal electrode 7A is connected to the power supply 13 via a second switch 32C, and the second most proximal electrode 7B is connected to the power supply 13 via a second switch 32D. In addition, the first most distal electrode 6A is connected to the electrocardiograph 50 via a first switch 31A, the first most proximal electrode 6B is connected to the electrocardiograph 50 via a first switch 31B, the second most distal electrode 7A is connected to the electrocardiograph 50 via a first switch 31C, and the second most proximal electrode 7B is connected to the electrocardiograph 50 via a first switch 31D.

[0051] The one or more first switches and the one or more second switches may be different types of switches, but it is preferable to use the same type of switch, which simplifies the control of the system 1.

[0052] The one or more first switches and the one or more second switches may each be a single-pole, single-throw type or a multi-pole, single-throw type, but a multi-pole, single-throw type is preferred. A single-pole, single-throw type allows each switch to be operated individually, making it easier to apply voltage only to specific electrodes. A multi-pole, single-throw type allows multiple switches to be operated in conjunction with a single operation, improving the accuracy of the timing at which voltage is applied to each electrode.

[0053] In the first mode (cardiac potential measurement mode) of the switching unit 30, it is preferable that the first switches 31A to 31D are ON and the second switches 32A to 32D are OFF. This allows electrocardiographic signals from the electrode unit 5 to be measured. In the second mode (defibrillation mode) of the switching unit 30, it is preferable that the first switches 31A to 31D are OFF and the second switches 32A to 32D are ON. This prevents a large current from accidentally flowing from the power supply 13 to the electrocardiograph 50, and allows defibrillation by outputting a DC voltage from the power supply 13 to each electrode.

[0054] In the system 1, as shown in Figures 5 and 2, after an enabling signal is generated from the enabling signal generating unit 21, the first switches 31A to 31D are turned from ON to OFF, and then, as shown in Figures 2 and 3, the second switches 32A to 32D are turned from OFF to ON, and then the power supply 13 is controlled to apply a voltage to the electrode unit 5. Therefore, regardless of parasitic capacitance of the power supply side circuit, it is possible to measure electrocardiographic signals while reducing noise while the catheter 2 is connected to the electrocardiograph 50. Furthermore, because the second switches 32A to 32D are turned from OFF to ON while the first switches 31A to 31D are in the OFF state, it is possible to prevent damage to the electrocardiograph 50 due to a large current flowing from the power supply 13 to the electrocardiograph 50 side.

[0055] The system 1 preferably has one or more operation units 40 for performing various operations such as turning on / off the electrical device 10, setting the amount of applied energy, charging voltage, applying voltage, selecting application electrodes, etc. Known input means such as a push button switch or a lever can be used as the operation unit.

[0056] The system 1 may have a main power switch 41 for turning on and off the main power of the electrical device 10. Examples of the main power switch 41 include a push button switch, a slide switch, and a rocker switch. When the main power switch 41 is turned on, an intracardiac potential may be measured by the electrode portion 5 of the catheter 2. When the main power switch 41 is turned on, the system may enter a cardiac potential measurement mode.

[0057] The system 1 may have an applied energy setting switch 42 for setting the amount of applied energy. Examples of the applied energy setting switch 42 include a touch panel, a dial switch, and a push button switch.

[0058] The system 1 may have a charging switch 43 for instructing the start of energy charging. Examples of the charging switch 43 include a touch panel, a push button switch, etc. When the charging switch 43 is turned on, it is preferable that the permission signal generating unit 21 generates a signal to instruct the power source 13 to start charging energy. Then, it is preferable that charging of a capacitor preferably included in the power source 13 is started upon receiving the signal from the permission signal generating unit 21.

[0059] The system 1 may have an application execution switch 44 for instructing the start of voltage application. Examples of the application execution switch 44 include a touch panel, a push button switch, and the like. When the application execution switch 44 is turned on, it is preferable that the permission signal generating unit 21 generates an permission signal that permits the application of voltage for defibrillation. This allows the user to operate the application execution switch 44 and apply voltage at the user's timing.

[0060] When the first electrode group 6 includes a plurality of electrodes and / or the second electrode group 7 includes a plurality of electrodes, the defibrillation electrical device 10 may have an electrode selection switch 45 for selecting the electrode to which the voltage is to be applied. Examples of the electrode selection switch 45 include a touch panel and a push button switch.

[0061] At least one of the main power switch 41, the applied energy setting switch 42, the charging switch 43, the application execution switch 44, and the electrode selection switch 45 is preferably connected to the switching unit 30 including a first switch and a second switch. At least one of the main power switch 41, the applied energy setting switch 42, the charging switch 43, the application execution switch 44, and the electrode selection switch 45 is preferably connected to the power supply 13. At least one of the main power switch 41, the applied energy setting switch 42, the charging switch 43, the application execution switch 44, and the electrode selection switch 45 is preferably connected to the control unit 20. As a result, input signals from the various operation switches are transmitted to the control unit 20. At least one of the main power switch 41, the applied energy setting switch 42, the charging switch 43, the application execution switch 44, and the electrode selection switch 45 may be connected to the power output control unit 24, which will be described later. At least one of the main power switch 41, the applied energy setting switch 42, the charging switch 43, the application execution switch 44, and the electrode selection switch 45 is preferably provided in the electrical device 10.

[0062] As shown in FIG. 2, the system 1 preferably includes a control unit 20 connected to the first switches 31A to 31D and the second switches 32A to 32D. The control unit 20 is preferably connected to the switching unit 30. This allows the control unit 20 to control each switch of the switching unit 30, allowing DC voltage from the power supply 13 to be output to each electrode, thereby enabling defibrillation by voltage application. The control unit 20 is preferably connected to an input unit 22, which will be described later. This allows the ON / OFF switching of each switch of the switching unit 30 to be controlled based on an electrocardiogram signal input from the input unit 22. Note that, to avoid complicating FIG. 2, the control unit 20 is connected to the first switch group 31 and the second switch group 32 in FIG. 2; however, it is preferable that the control unit 20 be connected to each of the first switches 31A to 31D, and that the control unit 20 be connected to each of the second switches 32A to 32D. Although not shown, the control unit 20 may have a first control unit that controls the ON / OFF switching of the first switches 31A to 31D, and a second control unit that controls the ON / OFF switching of the second switches 32A to 32D.

[0063] As shown in FIG. 2, the system 1 preferably includes a first delay unit 23 connected to the second switches 32A-32D and configured to delay the activation timing of the second switches 32A-32D so that the second switches 32A-32D change from OFF to ON after a first predetermined time has elapsed since the first switches 31A-31D changed from ON to OFF. By providing the first delay unit 23 in this manner, the activation timing of the first and second switches can be reliably shifted, thereby reducing noise during electrocardiogram signal measurement and preventing damage to the electrocardiograph 50. A known delay circuit, such as an RC circuit, can be used as the first delay unit 23. While the first delay unit 23 is shown connected to the second switch group 32 to avoid overcomplicating FIG. 2, it is preferable that the first delay unit 23 be connected to each of the second switches 32A-32D.

[0064] To ensure that the second switches 32A to 32D are turned ON after the first switches 31A to 31D are turned OFF, the first predetermined time is preferably 5 ms or more, more preferably 8 ms or more, and even more preferably 10 ms or more, and is preferably 30 ms or less, more preferably 25 ms or less, and even more preferably 20 ms or less.

[0065] 2, in the system 1, a power supply output control unit 24 is preferably disposed in the connection path between the power supply 13 and the second switches 32A to 32D. The power supply output control unit 24 can output the voltage input from the power supply 13 as pulsed power. By switching the polarity with the power supply output control unit 24, the polarity of the output from the first electrode group 6 and the second electrode group 7 can be reversed.

[0066] The power output control unit 24 has third switches 33A-33B, and is preferably controlled so that, for example, after the second switches 32A-32D are turned from OFF to ON as shown in Figures 2 and 3, the third switches 33A-33B are turned from OFF to ON as shown in Figures 3 and 4, and then the power supply 13 applies a voltage to the electrode unit 5. By turning the third switch from OFF to ON, the DC voltage from the power supply 13 is output to the electrodes via the third switch. This provides the power supply 13 with a fail-safe function that can prevent voltage from being unintentionally applied to the patient when the second switch fails, for example.

[0067] The power output control unit 24 may be provided with only one third switch or with multiple third switches. When the system 1 has multiple second switches and multiple third switches, one third switch may be connected to each second switch. In Fig. 2, the third switch 33A is connected to the second switches 32A and 32B so as to correspond to the electrodes 6A and 6B, and the third switch 33B is connected to the second switches 32C and 32D so as to correspond to the electrodes 7A and 7B.

[0068] The number of third switches is not particularly limited, but it is preferable that at least one third switch is provided for the anode side of the power source 13 and at least one third switch is provided for the cathode side of the electrode 13. Furthermore, at least one third switch may be provided for each electrode in the first electrode group 6, and at least one third switch may be provided for each electrode in the second electrode group 7.

[0069] The third switch may be, for example, a relay switch or a semiconductor switch. Examples of semiconductor switch elements include an IGBT, a MOSFET, a thyristor, an element using a SiC semiconductor, and an element using a GaN semiconductor.

[0070] The third switch, like the first and second switches, may be of a single-pole, single-throw type or a multi-pole, single-throw type, but is preferably of a multi-pole, single-throw type.

[0071] As shown in Fig. 2, an impedance measuring unit 25 is preferably disposed in the connection path between the power supply 13 and the second switches 32A to 32D, and impedance measurement is preferably started by the impedance measuring unit 25 after the second switches 32A to 32D are turned from OFF to ON. The impedance measuring unit 25 preferably measures the impedance between two electrodes of the electrode unit 5 or between the first electrode group 6 and the second electrode group 7. Measuring the impedance makes it possible to set an application waveform suited to the patient. It is preferable that the impedance measurement by the impedance measuring unit 25 is completed before voltage application.

[0072] 2, the system 1 preferably includes a second delay unit 26 that is connected to the impedance measurement unit 25 and delays the operation timing of the impedance measurement unit 25 so that impedance measurement starts after a second predetermined time has elapsed after the second switches 32A to 32D are turned from OFF to ON. By providing the second delay unit 26 in this manner, the operation timing of the impedance measurement unit 25 can be reliably delayed. A known delay circuit such as an RC circuit can be used as the second delay unit 26.

[0073] In order to reliably measure the impedance after the second switches 32A to 32D are turned ON, the second predetermined time is preferably 5 ms or more, more preferably 8 ms or more, and even more preferably 10 ms or more, and the second predetermined time is preferably 20 ms or less, more preferably 18 ms or less, and even more preferably 15 ms or less.

[0074] It is preferable that the power supply 13 be controlled to apply a voltage to the electrode unit 5 after the impedance measurement unit 25 has finished measuring the impedance. More preferably, after the application execution switch 44 is input, the following operations are performed in this order: generation of an enable signal from the enable signal generating unit 21, switching of the first switch from ON to OFF, switching of the second switch from OFF to ON, measurement of the impedance by the impedance measuring unit 25, and application of a voltage to the electrode unit 5 by the power supply 13. Furthermore, if the system 1 has third switches 33A and 33B, it is preferable that after the impedance measurement by the impedance measuring unit 25 has finished, the third switches 33A and 33B are switched from OFF to ON, and then the power supply 13 applies a voltage to the electrode unit 5.

[0075] Preferably, the system 1 is controlled so that after the first delay unit 23 turns the second switch from OFF to ON after a first predetermined time has elapsed, the impedance is measured by the impedance measuring unit 25 after a second predetermined time has elapsed after the second delay unit 26, and then the power supply 13 is controlled to apply a voltage to the electrode unit 5.

[0076] After the charging switch 43 is turned on, the impedance measurement unit 25 may start measuring the impedance. That is, the impedance measurement may start and / or end before the application execution switch 44 is turned on. After the charging switch 43 is turned on, it is preferable that the second switch be turned from OFF to ON, as shown in FIGS. 5 and 6 . By switching the switches in this manner, the impedance between the two electrodes of the electrode unit 5 is measured. Before the impedance measurement unit 25 starts measuring the impedance, the first switch may be ON or OFF, but the second switch is ON. After the impedance measurement, it is preferable that the second switch be turned from ON to OFF. At this time, it is preferable that the first switch remain ON.

[0077] A resistor may be disposed in the connection path between the electrode unit 5 and the electrocardiograph 50. For example, in FIG. 2 , electrode 6A of the first electrode group 6 is connected to the electrocardiograph 50 via resistor 38A, electrode 6B of the first electrode group 6 is connected to the electrocardiograph 50 via resistor 38B, electrode 7A of the second electrode group 7 is connected to the electrocardiograph 50 via resistor 38C, and electrode 7B of the second electrode group 7 is connected to the electrocardiograph 50 via resistor 38D. The resistors prevent the electrocardiograph 50 from being damaged by the application of an overvoltage. It is more preferable that each resistor has a resistance of 200 Ω or less. Setting the resistance to 200 Ω or less prevents the electrocardiograph 50 from being damaged by the application of an overvoltage, and also allows the waveform of the intracardiac potential acquired by the electrode unit 5 to be transmitted to the electrocardiograph 50 without distortion. The resistance may be 150 Ω or less, 100 Ω or less, 50 Ω or more, or 70 Ω or more.

[0078] Although not shown, the power supply 13 may be provided with a protection circuit that protects each switch from a high voltage that occurs when the switch is turned off, for example, thereby preventing damage to each switch.

[0079] 1 and 2, the system 1 is preferably connected to an electrocardiograph 50. The electrocardiograph 50 is a device that creates an electrocardiogram waveform (an electrocardiogram waveform) based on an electrocardiogram signal (also called an electrocardiogram signal or ECG signal) that measures potential changes that occur between electrodes inserted into the heart, between electrodes attached to the body surface, or between an electrode inserted into the heart and an electrode attached to the body surface. The vertical axis of the electrocardiogram waveform represents potential (e.g., in mV), and the horizontal axis represents time (e.g., in seconds).

[0080] The electrocardiograph 50 may have an amplifier circuit that amplifies the electrocardiographic signal measured by the electrodes. The amplifier circuit may be, for example, a differential amplifier circuit. In the electrocardiograph 50, a filter circuit may be connected to the amplifier circuit. The filter circuit may perform processing such as removing noise and baseline fluctuations from the signal amplified by the amplifier circuit. The filter circuit may be connected downstream of the amplifier circuit. The electrocardiograph 50 may have an analog-to-digital conversion circuit (AD conversion circuit) that converts an analog signal to a digital signal. The AD conversion circuit may be connected downstream of the amplifier circuit or the filter circuit. The electrocardiograph 50 may have a display unit for displaying the electrocardiographic waveform. Examples of the display unit include a liquid crystal display. While known electrocardiographs 50 can be used, it is preferable that the electrocardiograph 50 create an electrocardiographic waveform based on intracardiac potentials measured by the electrode unit 5 of the catheter 2. The system 1 may have a display device provided separately from the electrocardiograph 50. Examples of the display device include a computer, an external monitor, a mobile phone, a smartphone, and a tablet terminal.

[0081] For example, as shown in FIGS. 1 and 2 , the system 1 preferably includes an input unit 22 to which an electrocardiographic signal is input, the input unit 22 being connected to an electrocardiograph 50. This allows the first switch and the second switch to be controlled to switch from a cardiac potential measurement mode to a defibrillation mode, or vice versa, based on the electrocardiographic signal. The defibrillation electrical device 10 included in the system 1 preferably includes the input unit 22. The input unit 22 is preferably disposed in the control unit 20. The input unit 22 may be part of a circuit constituting the control unit 20, an input terminal physically connected to a device that measures the electrocardiographic signal, or part of a wireless communication device that receives the electrocardiographic signal. The electrocardiographic signal input to the input unit 22 may be obtained based on an intracardiac potential measured by electrodes inserted into the heart, or may be obtained based on a body surface potential measured by electrodes attached to the body surface.

[0082] For example, as shown in FIG. 2 , the system 1 preferably includes a detector 27 connected to the input unit 22 and configured to detect R waves using the electrocardiographic signal input to the input unit 22. In the treatment of atrial fibrillation, voltage must be applied to the heart during the absolute refractory period to prevent the ventricular muscle from responding. Therefore, voltage application is generally synchronized with the R wave. Therefore, detecting R waves with the detector 27 can prevent stimulation of the heart outside the absolute refractory period. The detector 27 is preferably disposed in the control unit 20. The detector 27 may be part of a circuit constituting the control unit 20, an input terminal physically connected to a device that measures the electrocardiographic signal, or part of a wireless communication device that receives the electrocardiographic signal. The defibrillation electrical device 10 included in the system 1 preferably includes the detector 27. The detector 27 preferably detects the peak of an R wave from the electrocardiographic signal. Furthermore, the detector 27 preferably detects at least one of the peaks of a P wave and a Q wave from the electrocardiographic signal.

[0083] The electrocardiograph 50 may be connected to the power source 13. For example, the electrocardiograph 50 may be connected to the defibrillation electrical device 10 including the power source 13. When the electrocardiograph 50 is connected to the power source 13, it is preferable that an overvoltage protection circuit that protects the electrocardiograph 50 from overvoltage is provided in the connection path between the power source 13 and the electrocardiograph 50. By providing the overvoltage protection circuit, it is possible to prevent damage to the electrocardiograph 50 due to application of overvoltage to the electrocardiograph 50. An overvoltage protection circuit is a circuit that has the function of suppressing overvoltage and providing protection when an input or output becomes overvoltage due to an external surge voltage, a device abnormality, or the like.

[0084] At least one of the functions of the system 1, for example, the functions of the control unit 20, the enabling signal generating unit 21, the input unit 22, the first delay unit 23, the power output control unit 24, the impedance measuring unit 25, the second delay unit 26, and the detection unit 27, may be realized by hardware or software. Examples of the hardware include logic circuits formed in integrated circuits such as LSIs (Large Scale Integrations) and ASICs (Application Specific Integrated Circuits).

[0085] The system 1 may include a computer that executes instructions of a program, which is software for realizing at least one function of the control unit 20, the enabling signal generating unit 21, the input unit 22, the first delay unit 23, the power output control unit 24, the impedance measuring unit 25, the second delay unit 26, and the detection unit 27. The computer preferably includes a processor and a computer-readable recording medium storing the program. The processor executes the program stored in the computer-readable recording medium to realize the above functions. A CPU (Central Processing Unit) can be used as the processor. A ROM (Read Only Memory) or the like can be used as the recording medium. The recording medium can also include a RAM (Random Access Memory). The program can be supplied to the computer via any transmission medium capable of transmitting the program. Examples of the transmission medium include a communication network and a communication line.

[0086] A control method for an intracardiac defibrillation catheter system 1 according to one embodiment of the present invention will be described with reference to Figures 1 to 9. Figure 7 is a flowchart showing a control method for an intracardiac defibrillation catheter system according to one embodiment of the present invention. Figures 8 and 9 are flowcharts showing modified examples of the control method for the intracardiac defibrillation catheter system shown in Figure 7.

[0087] 1 and 2, the system 1 to be controlled includes a catheter 2 having a longitudinal axis, an electrode unit 5 disposed at the distal portion of the catheter 2, a power supply 13 that applies a voltage to the electrode unit 5, an enable signal generating unit 21 connected to the power supply 13 and that generates an enable signal that enables the application of a voltage for defibrillation, first switches 31A to 31D connected to the power supply 13, and second switches 32A to 32D connected to the power supply 13 and disposed closer to the power supply 13 than the first switches 31A to 31D, and the first switches 31A to 31D and the second switches 32A to 32D are independent of each other. For details of these configurations, please refer to the above description.

[0088] As shown in FIG. 7 , the control method includes the steps of generating an enable signal from the enable signal generating unit 21 (step S1), switching the first switches 31A-31D from ON to OFF (step S2, FIGS. 5 to 2), switching the second switches 32A-32D from OFF to ON (step S3, FIGS. 2 to 3), and applying a voltage to the electrode unit 5 by the power supply 13 (step S4). According to this control method, the first switch is switched from ON to OFF, and then the second switch is switched from OFF to ON. This allows electrocardiographic signals to be measured while reducing noise while the catheter 2 is connected to the electrocardiograph 50, regardless of parasitic capacitance of the power supply circuit. Furthermore, because the second switch is switched from OFF to ON while the first switch is OFF, damage to the electrocardiograph 50 due to a large current flowing from the power supply 13 to the electrocardiograph 50 can be prevented.

[0089] In step S1, it is preferable that the permission signal is generated from the permission signal generating unit 21 based on an input signal from the application execution switch 44. It is more preferable that the permission signal is generated from the permission signal generating unit 21 after the input signal is issued from the application execution switch 44. If the application execution switch 44 is a push button switch, it is preferable that the permission signal is generated from the permission signal generating unit 21 by pressing and holding the push button switch for a predetermined time, for example, from one second to three seconds.

[0090] In step S4, a voltage is applied to the R wave of the electrocardiogram signal. In step S4, DC voltages of opposite polarities are preferably applied to the electrodes of the first electrode group 6 and the electrodes of the second electrode group 7. The current waveform may be biphasic, in which the polarity is reversed midway, or monophasic, in which the polarity is constant. However, biphasic waveforms are preferred because they are believed to enable stimulation with less energy. The current energy applied to the living body can be set to, for example, 1 J or more and 30 J or less.

[0091] Step S2 is preferably performed after step S1. Step S3 is preferably performed after step S2. Step S4 is preferably performed after step S3. Steps are preferably performed in the order of step S1, step S2, step S3, and step S4.

[0092] 2, if the system 1 further includes a first delay unit 23 connected to the second switches 32A to 32D and delaying the activation timing of the second switches 32A to 32D, the control method may include a step (step S3, FIGS. 2 and 3) in which the first switches 31A to 31D are turned from ON to OFF after a first predetermined time has elapsed by the first delay unit 23, following a step (step S2, FIGS. 5 to 2) in which the first switches 31A to 31D are turned from OFF to ON. The above descriptions can be referred to for the description of the first delay unit 23 and the first predetermined time.

[0093] It is preferable that the system 1 has a control unit 20, and in steps S2 and S3, the control unit 20 controls the switches so that each switch is turned ON or OFF.

[0094] A control method for system 1 according to another embodiment of the present invention will be described below with reference to Fig. 8. As shown in Fig. 2, system 1 preferably has at least one of a main power switch 41, an applied energy setting switch 42, a charging switch 43, an application execution switch 44, and an electrode selection switch 45, and more preferably has all of them.

[0095] First, a step (step S11) is preferably performed in which the main power supply of the electrical defibrillation device 10 included in the system 1 is turned on. In step S11, the main power supply of the electrical defibrillation device 10 is preferably turned on based on an input signal from the main power switch 41. The fact that the main power switch 41 has issued an input signal is transmitted to the control unit 20. After completion of step S11, the first switches 31A to 31D may be OFF and the second switches 32A to 32D may be OFF. Alternatively, after completion of step S11, the first switches 31A to 31D may be ON and the second switches 32A to 32D may be OFF after a predetermined time has elapsed. In the latter case, intracardiac potentials can be measured in the next step S12. The predetermined time may be, for example, 1 ms or more, 3 ms or more, 5 ms or more, or 20 ms or less, 15 ms or less, or 10 ms or less.

[0096] An intracardiac potential may be measured by the electrode unit 5 of the catheter 2 (step S12). Before the start of step S12, it is preferable that the first switches 31A to 31D are ON and the second switches 32A to 32D are OFF.

[0097] It is preferable to carry out a step of setting the applied energy (step S13). In step S13, it is preferable to set the magnitude of the applied energy based on an input signal from the applied energy setting switch 42. After the input signal is generated from the applied energy setting switch 42, it is preferable that the control unit 20 controls the power supply 13 to set the voltage to be applied to the electrode. It is preferable that the electrode to be applied is selected using the electrode selection switch 45 before or after step S13. After the input signal is generated from the electrode selection switch 45, it is preferable that the control unit 20 controls the selection of the electrode to be applied.

[0098] It is preferable that a step (step S14) of inputting the charging switch 43 is performed. In step S14, it is preferable that the second switches 32A to 32D are turned from OFF to ON based on the input signal from the charging switch 43. After the input signal is generated from the charging switch 43, it is preferable that the control unit 20 performs control to perform steps S15 and / or S16 described below. It is preferable that the first switches 31A to 31D remain ON even after the charging switch 43 is input in step S14.

[0099] A step (step S15) of measuring impedance by the impedance measurement unit 25 is preferably performed. In step S15, the impedance between the multiple electrodes of the electrode unit 5 is preferably measured. In step S15, the impedance between the first electrode group 6 and the second electrode group 7 of the electrode unit 5 may be measured. For example, it is more preferable to measure the impedance between the electrodes of the first electrode group 6 and the electrodes of the second electrode group 7. The second switches 32A to 32D are preferably ON from the start of impedance measurement to its completion. After the start of impedance measurement, the second switches 32A to 32D are preferably turned from ON to OFF. Impedance measurement can be performed, for example, by an impedance measurement circuit. The AC voltage applied in impedance measurement has a frequency and voltage sufficient to calculate impedance, and may be a voltage sufficiently smaller than the voltage applied during defibrillation. The shorter the impedance measurement time, the better, preferably several tens to several hundreds of milliseconds. After an input signal is generated from the charging switch 43 in step S14, impedance measurement may be started in step S15.

[0100] A step (step S16) is preferably performed in which the capacitor of the power supply 13 is charged with the applied energy set in step S13. If the impedance measurement result in step S15 is within a predetermined range, step S16 is preferably performed. After an input signal is generated from the charging switch 43 in step S14, charging of energy is preferably started in step S16. From the start to the completion of step S16, the first switches 31A to 31D are preferably ON, and the second switches 32A to 32D are preferably OFF.

[0101] 8, step S16 is started after step S15, but step S16 may be started after step S15 is started but before its completion. Alternatively, step S15 may be started after step S16 is completed, or after step S16 is started but before its completion. In other words, charging of energy to the capacitor and measurement of impedance may be performed in parallel.

[0102] A step (step S17) is performed in which an enabling signal is generated from the enabling signal generating unit 21. In step S17, it is preferable that the enabling signal is generated from the enabling signal generating unit 21 after an input signal is generated from the application execution switch 44. If the application execution switch 44 is a push button switch, it is preferable that the enabling signal is generated from the enabling signal generating unit 21 by pressing and holding the push button switch for a predetermined period of time.

[0103] The first switches 31A to 31D are turned from ON to OFF (step S18). For details of step S18, see the description of step S2.

[0104] The second switches 32A to 32D are turned from OFF to ON (step S19). For details of step S19, see the description of step S3.

[0105] As shown in FIG. 2, if the intracardiac defibrillation catheter system 1 further includes a power output control unit 24 arranged in the connection path between the power source 13 and the second switches 32A to 32D, and the power output control unit 24 includes third switches 33A to 33B, the control method may include a step of changing the second switches 32A to 32D from OFF to ON (step S19, FIGS. 2 and 3), followed by a step of changing the third switches 33A to 33B from OFF to ON (step S20, FIGS. 3 and 4).

[0106] The power supply 13 applies a voltage to the electrode unit 5 (step S21). If the control method includes step S20, it is preferable to perform step S21 after step S20. It is also preferable to perform step S19 after step S18, step S20 after step S19, and step S21 after step S20.

[0107] A modified example of the control method for the intracardiac defibrillation catheter system 1 shown in Fig. 8 will be described with reference to Fig. 9. The control method shown in Fig. 9 differs from the control method shown in Fig. 8 in that impedance measurement is performed immediately before voltage application, more specifically, after the application execution switch 44 is turned on.

[0108] First, it is preferable to perform a step (step S31) of turning on the main power supply of the defibrillation electrical device 10 of the system 1. An intracardiac potential may be measured by the electrode portion 5 of the catheter 2 (step S32). Next, it is preferable to perform a step (step S33) of setting the applied energy. It is preferable to perform a step (step S34) of turning on the charging switch 43. For details of steps S31 to S34, please refer to the descriptions of steps S11 to S14, respectively.

[0109] After step S34, a step (step S35) is preferably performed in which the capacitor of power supply 13 is charged with the applied energy set in step S13. After an input signal is generated from charging switch 43 in step S34, charging of energy is preferably started in step S35. From the start to the completion of step S35, first switches 31A to 31D are preferably ON, and second switches 32A to 32D are preferably OFF.

[0110] A step (step S36) is performed in which an enabling signal is generated from the enabling signal generating unit 21. For details of step S36, see the description of step S17.

[0111] The first switches 31A to 31D are turned from ON to OFF (step S37). For details of step S37, see the descriptions of steps S2 and S18.

[0112] The second switches 32A to 32D are then turned from OFF to ON (step S38). For details of step S38, please refer to the descriptions of steps S3 and S19.

[0113] 2, if the system 1 further includes an impedance measuring unit 25 disposed in the connection path between the power supply 13 and the second switches 32A to 32D, a step (step S39) of measuring the impedance by the impedance measuring unit 25 is preferably performed. In step S39, the second switch is preferably ON from the start of impedance measurement until the measurement is completed. Step S39 is preferably performed after step S38 is completed. For other details of the impedance measurement, refer to the description of step S15.

[0114] If the system 1 is connected to the impedance measuring unit 25 and further includes a second delay unit 26 that delays the activation timing of the impedance measuring unit 25, it is preferable to start a step (step S39) of measuring the impedance by the impedance measuring unit 25 after a second predetermined time has elapsed after the step (step S38) of turning the second switches 32A to 32D from OFF to ON. For the second delay unit 26 and the second predetermined time in step S39, the above descriptions of the second delay unit 26 and the second predetermined time can be referenced as appropriate.

[0115] It is preferable to perform a step (step S40) in which the third switch is turned from OFF to ON. For an explanation of step S40, please refer to the explanation of step S20.

[0116] A step (step S41) is performed in which the power supply 13 applies a voltage to the electrode portion 5. For an explanation of step S41, the explanations of steps S4 and S21 can be referred to.

[0117] This application claims the benefit of priority based on Japanese Patent Application No. 2024-50708, filed on March 27, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-50708, filed on March 27, 2024, are incorporated herein by reference.

[0118] 1: Intracardiac defibrillation catheter system 2: Catheter 3: Distal tip 4: Handle 5: Electrode section 10: Defibrillation electrical device 13: Power supply 15: First connection section 20: Control section 21: Enabling signal generating section 22: Input section 23: First delay section 24: Power supply output control section 25: Impedance measuring section 26: Second delay section 27: Detection section 30: Switching section 31A, 31B, 31C, 31D: First switch 32A, 32B, 32C, 32D: Second switch 33A, 33B: Third switch 35: Wiring connection section 38A, 38B, 38C, 38D: Resistor 41: Main power switch 42: Applied energy setting switch 43: Charging switch 44: Application execution switch 45: Electrode selection switch 50: Electrocardiograph

Claims

1. An intracardiac defibrillation catheter system comprising: a catheter having a longitudinal axis direction; an electrode portion disposed in a distal portion of the catheter; a power source for applying a voltage to the electrode portion; an enable signal generating portion connected to the power source and generating an enable signal to enable application of a voltage for defibrillation; a first switch connected to the power source; and a second switch connected to the power source and disposed closer to the power source than the first switch, wherein the first switch and the second switch are independent of each other, and the first switch changes from ON to OFF after the enable signal generating portion generates the enable signal, and then the second switch changes from OFF to ON, and the power source is controlled to apply a voltage to the electrode portion.

2. An intracardiac defibrillation catheter system as described in claim 1, further comprising a first delay unit connected to the second switch, which delays the activation timing of the second switch so that the second switch changes from OFF to ON after a first predetermined time has elapsed after the first switch changes from ON to OFF.

3. The intracardiac defibrillation catheter system according to claim 2, wherein the first predetermined time is between 5 ms and 30 ms.

4. An intracardiac defibrillation catheter system according to claim 1 or 2, wherein a power output control section is disposed in a connection path between the power supply and the second switch, the power output control section has a third switch, and after the second switch is turned from OFF to ON, the third switch is turned from OFF to ON, and thereafter the power supply is controlled to apply a voltage to the electrode section.

5. An intracardiac defibrillation catheter system according to claim 1 or 2, wherein an impedance measuring unit is disposed in a connection path between the power supply and the second switch, and when the second switch is turned from OFF to ON, the impedance measuring unit starts measuring impedance.

6. An intracardiac defibrillation catheter system as described in claim 5, further comprising a second delay unit connected to the impedance measuring unit and delaying the operation timing of the impedance measuring unit so that measurement of the impedance begins after a second predetermined time has elapsed after the second switch is turned from OFF to ON.

7. The intracardiac defibrillation catheter system according to claim 6, wherein the second predetermined time is between 5 ms and 20 ms.

8. An intracardiac defibrillation catheter system according to claim 1 or 2, comprising: an input unit to which an electrocardiogram signal is input and which is connected to an electrocardiograph; and a detection unit connected to said input unit and which detects R waves using the electrocardiogram signal input to said input unit.

9. An intracardiac defibrillation catheter system according to claim 1 or 2, further comprising a first connection part connected to an electrocardiograph, wherein the first switch is disposed closer to the first connection part than the second switch.

10. A control method for an intracardiac defibrillation catheter system comprising: a catheter having a longitudinal axis direction; an electrode portion disposed at a distal portion of the catheter; a power source for applying a voltage to the electrode portion; an enabling signal generating portion connected to the power source and generating an enabling signal to enable application of a voltage for defibrillation; a first switch connected to the power source; and a second switch connected to the power source and disposed closer to the power source than the first switch, wherein the first switch and the second switch are independent of each other, the control method for an intracardiac defibrillation catheter system comprising: a step of generating the enabling signal from the enabling signal generating portion; a step of turning the first switch from ON to OFF; a step of turning the second switch from OFF to ON; and a step of the power source applying a voltage to the electrode portion.

11. A method for controlling an intracardiac defibrillation catheter system according to claim 10, wherein the intracardiac defibrillation catheter system further comprises a first delay unit connected to the second switch and delaying the activation timing of the second switch, and after the step of turning the first switch from ON to OFF, the first delay unit performs a step of turning the second switch from OFF to ON after a first predetermined time has elapsed.

12. A control method for an intracardiac defibrillation catheter system according to claim 10 or 11, wherein the intracardiac defibrillation catheter system further comprises a power supply output control section disposed in a connection path between the power supply and the second switch, the power supply output control section having a third switch, and the method includes a step of turning the third switch from OFF to ON after the step of turning the second switch from OFF to ON, and the power supply applies a voltage to the electrode section after the third switch is turned ON.

13. A control method for an intracardiac defibrillation catheter system according to claim 10 or 11, wherein the intracardiac defibrillation catheter system further comprises an impedance measuring unit disposed in a connection path between the power supply and the second switch, and includes a step of measuring impedance by the impedance measuring unit after the second switch is turned from OFF to ON.

14. A method for controlling an intracardiac defibrillation catheter system according to claim 13, wherein the intracardiac defibrillation catheter system further comprises a second delay unit connected to the impedance measuring unit for delaying the timing of operation of the impedance measuring unit, and the step of measuring impedance by the impedance measuring unit is initiated a second predetermined time after the step of turning the second switch from OFF to ON.

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