Defibrillation catheter system

Abstract

This defibrillation catheter system has: a catheter; an electrode unit (5) that is provided to the catheter and has a first distal-most electrode (6A), a first proximal-most electrode (6B), a second distal-most electrode (7A), and a second proximal-most electrode (7B); a power source (13) incorporating one or more capacitors (14); and an output circuit (30) having eight switch elements (31 to 38) connected in parallel to each other. One end of each of the switch elements (31 to 38) is connected to the positive-electrode side or the negative-electrode side of the capacitor (14) without passing through another switch element, and the other end of each of the switch elements (31 to 38) is connected to an electrode of the electrode unit (5) without passing through another switch element.

Description

Defibrillation catheter system

[0001] The present invention relates to a defibrillation catheter system used for performing defibrillation in a cardiac chamber.

[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 defibrillation catheter systems. Defibrillation catheter systems are devices that directly apply electrical stimulation to the heart through electrodes attached to the surface of the catheter. Defibrillation catheter systems 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 to prevent the ventricular muscle from reacting. Stimulation of the heart outside the absolute refractory period may cause the ventricular muscle to react, leading to ventricular fibrillation. For this reason, in defibrillation catheter systems, voltage is applied in synchronization with the R wave. A direct current voltage is applied. Patent Documents 1 to 3 disclose examples of defibrillation catheter systems, each of which has a switching unit including a switch element for switching between a voltage application mode for defibrillation and an intracardiac potential measurement mode. For example, the switching unit controls the ON / OFF of a power supply switch and an electrocardiograph switch to switch the circuit, thereby switching the mode.

[0004] Generally, a biphasic electrical waveform, which requires less energy than a monophasic waveform, is used for the DC voltage applied during defibrillation. To use a biphasic waveform as the current waveform, the above-described system may include a power-side switch and an electrocardiograph-side switch in the output circuit, as well as a polarity-switching switch in the connection path between the power-side switch and the power supply for reversing the polarity of the current waveform. Therefore, when applying voltage, the power-side switch and the electrocardiograph-side switch in the switching unit are typically turned ON or OFF after detecting an R wave to switch from a mode other than voltage application to voltage application mode. Then, the polarity of the current waveform is switched by the polarity-switching switch, and voltage is applied to the electrodes of the catheter.

[0005] International Publication No. 2022 / 195644 International Publication No. 2023 / 026346 International Publication No. 2021 / 191988

[0006] Since it generally takes about 10 ms to detect an R wave, quick switching is required to avoid performing defibrillation during the absolute refractory period. Therefore, an object of the present invention is to provide a defibrillation catheter system that can quickly switch the switch required to apply voltage after detecting an R wave.

[0007] A defibrillation catheter system according to an embodiment of the present invention that can solve the above problems is as follows.[1] A catheter having a longitudinal axis direction; an electrode section having a first electrode group disposed in the catheter and including a first most distal electrode and a first most proximal electrode arranged in order from the distal side, and a second electrode group disposed in the catheter proximal to the first electrode group and including a second most distal electrode and a second most proximal electrode arranged in order from the distal side; a power supply that applies a voltage to the electrode section, the power supply having one or more built-in capacitors; and an output circuit having a first switch element and a second switch element connected in parallel to each other, a third switch element and a fourth switch element connected in parallel to each other, a fifth switch element and a sixth switch element connected in parallel to each other, and a seventh switch element and an eighth switch element connected in parallel to each other, wherein one end of the first switch element is connected to the anode side of the capacitor without passing through any other switch element, and the other end is connected to the first most distal electrode without passing through any other switch element, one end of the second switch element is connected to the cathode side of the capacitor without any other switch elements, and the other end is connected to the first most distal electrode without any other switch elements; one end of the third switch element is connected to the anode side of the capacitor without any other switch elements, and the other end is connected to the first most proximal electrode without any other switch elements; one end of the fourth switch element is connected to the cathode side of the capacitor without any other switch elements, and the other end is connected to the first most proximal electrode without any other switch elements; one end of the fifth switch element is connected to the anode side of the capacitor without any other switch elements, and the other end is connected to the second most distal electrode without any other switch elements; one end of the sixth switch element is connected to the cathode side of the capacitor without any other switch elements, and the other end is connected to the second most distal electrode without any other switch elements; one end of the seventh switch element is connected to the anode side of the capacitor without any other switch element and the other end is connected to the second-most proximal electrode without any other switch element; and one end of the eighth switch element is connected to the cathode side of the capacitor without any other switch element and the other end is connected to the second-most proximal electrode without any other switch element.

[0008] Furthermore, the defibrillation catheter system according to the embodiment is preferably any one of the following [2] to

[10] : [2] The catheter system further includes a control unit that controls ON / OFF of a switch element included in the output circuit, and a signal generating unit that generates a first signal that permits application of a voltage to the electrode unit, and after generation of the first signal from the signal generating unit, the control unit controls ON / OFF of the switch elements included in the output circuit so that at least one switch element connected to the cathode side of the capacitor is turned ON and then at least one switch element connected to the anode side of the capacitor is turned ON. [3] The defibrillation catheter system according to [2], wherein the signal generating unit further generates a second signal indicating completion of application of voltage to the electrode unit, and the control unit controls ON / OFF of the switch elements of the output circuit so that, after generation of the second signal from the signal generating unit, at least one switch element connected to the anode side of the capacitor is turned OFF and then at least one switch element connected to the cathode side of the capacitor is turned OFF. [4] The defibrillation catheter system according to any one of [1] to [3], wherein a difference in time when at least two or more of the first switch element, the third switch element, the fifth switch element, and the seventh switch element are turned ON is within 10 μs.[5] The catheter system according to any one of [1] to [4], further comprising: a control unit that controls ON / OFF of a switch element of the output circuit; and a signal generating unit that generates a first signal permitting application of a voltage to the electrode unit, wherein after generation of the first signal from the signal generating unit, the control unit controls ON / OFF of the switch element of the output circuit so that a current flows from the first most distal electrode to the second most proximal electrode and from the first most proximal electrode to the second most distal electrode, and then a current flows from the second most proximal electrode to the first most distal electrode and from the second most distal electrode to the first most proximal electrode. [6] The defibrillation catheter system according to [5], further comprising: a control unit that controls ON / OFF of the switch element of the output circuit by the control unit in the following order (i) to (viii) after generation of the first signal from the signal generating unit: (i) the sixth switch element ON and the eighth switch element ON, (ii) the first switch element ON and the third switch element ON, (iii) the first switch element OFF and the third switch element OFF, (iv) the sixth switch element OFF and the eighth switch element OFF, (v) the second switch element ON and the fourth switch element ON, (vi) the fifth switch element ON and the seventh switch element ON, (vii) the fifth switch element OFF and the seventh switch element OFF, and (viii) the second switch element OFF and the fourth switch element OFF. [7] The defibrillation catheter system according to any one of [1] to [6], wherein the power source has a first capacitor connected to the first most distal electrode and a second capacitor connected to the first most proximal electrode and having a maximum amount of electricity stored therein smaller than that of the first capacitor. [8] The defibrillation catheter system according to any one of [1] to [7], wherein the power supply has a third capacitor connected to the second most distal electrode and a fourth capacitor connected to the second most proximal electrode and having a maximum amount of electricity stored therein that is greater than that of the third capacitor.[9] The defibrillation catheter system according to any one of [1] to [8], wherein the electrodes included in the first electrode group and the electrodes included in the second electrode group are controlled so that potentials of different polarities are applied to each other, and the first most distal electrode and the first most proximal electrode are controlled so that potentials of the same polarity but different values ​​are applied to each other.

[10] The defibrillation catheter system according to any one of [1] to [9], further comprising a current detection circuit connected to a connection path between the power supply and the output circuit, and detecting whether a current flowing from the power supply to the output circuit exceeds a predetermined value.

[0009] The above-described defibrillation catheter system does not include a polarity-switching switch for energized electric waves, which is conventionally provided in the connection path between the power-side switch for mode switching and the capacitor. However, even without the polarity-switching switch, it is possible to switch the polarity of the energized electric waves by appropriately switching the first through eighth switch elements ON and OFF. This allows the circuit to be switched in a short time after the R wave is detected, thereby shortening the time from the detection of the R wave to the application of voltage. As a result, it is possible to prevent voltage from being applied during the absolute refractory period, further improving the safety of the procedure.

[0010] 1 is a schematic diagram of a defibrillation catheter system according to an embodiment of the present invention; 2 is a circuit diagram of a defibrillation catheter system according to an embodiment of the present invention; 3 is an example of a current waveform for a defibrillation catheter system according to an embodiment of the present invention; 4 is a circuit diagram showing the connections of a power supply, an output circuit, and an electrode unit of the defibrillation catheter system shown in FIG. 2, (i) showing the state of the sixth switch element and the eighth switch element ON; 5 is a circuit diagram showing the connections of a power supply, an output circuit, and an electrode unit of the defibrillation catheter system shown in FIG. 2, (ii) showing the state of the first switch element ON and the third switch element ON; 6 is a circuit diagram showing the connections of a power supply, an output circuit, and an electrode unit of the defibrillation catheter system shown in FIG. 2, (iii) showing the state of the first switch element OFF and the third switch element OFF; 7 is a circuit diagram showing the connections of a power supply, an output circuit, and an electrode unit of the defibrillation catheter system shown in FIG. 2, (iv) showing the state of the sixth switch element OFF and the eighth switch element OFF. 3 is a circuit diagram showing the connections of the power supply, output circuit, and electrode unit of the defibrillation catheter system shown in FIG. 2, (v) showing the states of the second switch element and the fourth switch element ON. FIG. 3 is a circuit diagram showing the connections of the power supply, output circuit, and electrode unit of the defibrillation catheter system shown in FIG. 2, (vi) showing the states of the fifth switch element and the seventh switch element ON. FIG. 3 is a circuit diagram showing the connections of the power supply, output circuit, and electrode unit of the defibrillation catheter system shown in FIG. 2, (vii) showing the states of the fifth switch element and the seventh switch element OFF. FIG. 3 is a circuit diagram showing the connections of the power supply, output circuit, and electrode unit of the defibrillation catheter system shown in FIG. 2, (viii) showing the states of the second switch element and the fourth switch element OFF. FIG. 3 is a circuit diagram showing a modification of the power supply, output circuit, and electrode unit shown in FIG. 3.

[0011] 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.

[0012] A defibrillation catheter system according to one embodiment of the present invention includes an electrode section including a catheter having a longitudinal axis, a first electrode group disposed on the catheter and including a first most distal electrode and a first most proximal electrode arranged in order from the distal side, and a second electrode group disposed on the catheter proximal to the first electrode group and including a second most distal electrode and a second most proximal electrode arranged in order from the distal side, a power supply that applies a voltage to the electrode section, the power supply including one or more capacitors, and a first switch element and a second switch element that are connected in parallel to each other. and an output circuit having a third switch element and a fourth switch element connected in parallel to each other, a fifth switch element and a sixth switch element connected in parallel to each other, and a seventh switch element and an eighth switch element connected in parallel to each other, wherein one end of the first switch element is connected to the anode side of the capacitor without passing through any other switch element, and the other end is connected to the first most distal electrode without passing through any other switch element, and one end of the second switch element is connected to the cathode side of the capacitor without passing through any other switch element, and the other end is connected to the first most distal electrode without passing through any other switch element. the third switch element has one end connected to the anode side of the capacitor without any other switch element and the other end connected to the first most proximal electrode without any other switch element; the fourth switch element has one end connected to the cathode side of the capacitor without any other switch element and the other end connected to the first most proximal electrode without any other switch element; the fifth switch element has one end connected to the anode side of the capacitor without any other switch element and the other end connected to the second most distal electrode without any other switch element. the sixth switch element has one end connected to the cathode side of the capacitor without any other switch element and the other end connected to the second most distal electrode without any other switch element; the seventh switch element has one end connected to the anode side of the capacitor without any other switch element and the other end connected to the second most proximal electrode without any other switch element; and the eighth switch element has one end connected to the cathode side of the capacitor without any other switch element and the other end connected to the second most proximal electrode without any other switch element.The above-described defibrillation catheter system does not include a polarity-switching switch for energized electric waves, which is conventionally provided in the connection path between the power-side switch for mode switching and the capacitor. However, even without the polarity-switching switch, it is possible to switch the polarity of the energized electric waves by appropriately switching the first through eighth switch elements ON and OFF. This allows the circuit to be switched in a short time after the R wave is detected, thereby shortening the time from the detection of the R wave to the application of voltage. As a result, it is possible to prevent voltage from being applied during the absolute refractory period, further improving the safety of the procedure.

[0013] A defibrillation catheter system according to one embodiment of the present invention will be described with reference to FIGS. 1 to 12. Hereinafter, the defibrillation catheter system may be simply referred to as a system. FIG. 1 is a schematic diagram of a system according to one embodiment of the present invention. FIG. 2 is a circuit diagram of a system according to one embodiment of the present invention. FIG. 3 is an example of a current waveform of a system according to one embodiment of the present invention. FIG. 4 is a circuit diagram showing (i) the sixth switch element and the eighth switch element in the ON state in the system shown in FIG. 2. FIG. 5 is a circuit diagram showing (ii) the first switch element and the third switch element in the ON state in the system shown in FIG. 2. FIG. 6 is a circuit diagram showing (iii) the first switch element and the third switch element in the OFF state in the system shown in FIG. 2. FIG. 7 is a circuit diagram showing (iv) the sixth switch element and the eighth switch element in the OFF state in the system shown in FIG. 2. FIG. 8 is a circuit diagram showing (v) the second switch element and the fourth switch element in the ON state in the system shown in FIG. 2. FIG. 9 is a circuit diagram showing the (vi) ON state of the fifth switch element and the seventh switch element in the system shown in FIG. 2 . FIG. 10 is a circuit diagram showing the (vii) OFF state of the fifth switch element and the seventh switch element in the system shown in FIG. 2 . FIG. 11 is a circuit diagram showing the (viii) OFF state of the second switch element and the fourth switch element in the system shown in FIG. 2 . FIG. 12 is a circuit diagram showing a modification of the power supply shown in FIGS. 4 to 11 . As shown in FIGS. 1 and 2 , the system 1 includes a catheter 2, an electrode unit 5, a power supply 13, and an output circuit 30. As shown in FIGS. 1 and 2 , the system 1 includes a defibrillation electrical device 10, which may include the electrode unit 5, the power supply 13, and the output circuit 30. Hereinafter, the defibrillation electrical device may be simply referred to as an electrical device.

[0014] 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 , the catheter 2 is provided with an electrode unit 5 including a first electrode group 6 including a first most distal electrode 6A and a first most proximal electrode 6B arranged in order from the distal side, and a second electrode group 7 arranged proximally relative to the first electrode group 6 of the catheter 2 and including a second most distal electrode 7A and a second most proximal electrode 7B arranged in order from the distal side. The electrode unit 5 is preferably provided in the distal portion of the catheter 2. The electrode unit 5 is composed of at least four electrodes, and preferably includes at least two pairs of positive and negative electrodes.

[0015] 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 an electrocardiogram waveform or electrocardiogram data) can be obtained using an electrocardiograph 70 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 70.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] As shown in FIGS. 1 to 3 , the electrode unit 5 includes multiple electrodes. Specifically, the first electrode group 6 includes a first most distal electrode 6A and a first most proximal electrode 6B, arranged in order from the distal end, and a second electrode group 7 includes a second most distal electrode 7A and a second most proximal electrode 7B, arranged in order from the distal end, and disposed proximal to the first electrode group 6 of the catheter 2. 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 each electrode can be measured by measuring the potential difference between adjacent electrodes. Since the first electrode group 6 and the second electrode group 7 each include multiple electrodes, voltage can be applied over a wide area of ​​the heart, enabling efficient defibrillation. The first electrode group 6 is preferably positioned corresponding to the coronary sinus, and the second electrode group 7 is preferably positioned corresponding to the right atrium. FIG. 1 shows an example in which the first electrode group 6 has eight electrodes and the second electrode group 7 has eight electrodes, but it is sufficient for the first electrode group 6 to have at least two electrodes, a first most distal electrode 6A and a first most proximal electrode 6B, and it is sufficient for the second electrode group 7 to have at least two electrodes, a second most distal electrode 7A and a second most proximal electrode 7B.

[0020] 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.

[0021] It is preferable to apply DC voltages of different polarities to the electrodes of the first electrode group 6 and the electrodes of the second electrode group 7. Specifically, it is preferable to apply DC voltages of different polarities 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 vice versa. The current waveform may be monophasic, in which the polarity is constant, but is preferably biphasic, in which the polarity is reversed midway, as shown in Figure 3. A biphasic waveform can eliminate defibrillation 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.

[0022] 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. When applying a biphasic DC voltage as shown in Fig. 3, a negative voltage is applied to the electrodes in the first electrode group 6 and a positive voltage is applied to the electrodes in the second electrode group 7 in the first half of the current flow, thereby causing a current to flow from the right atrium toward the coronary sinus. In the second half of the current flow, a positive voltage is applied to the electrodes in the first electrode group 6 and a negative voltage is applied to the electrodes in the second electrode group 7, thereby causing a current to flow from the coronary sinus toward the right atrium.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The electrode unit 5 is preferably connected to the electrocardiograph 70. The electrode unit 5 is preferably connected to the electrocardiograph 70 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 70.

[0028] 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.

[0029] The third electrode group 8 is preferably connected to the electrocardiograph 70. Although Fig. 2 shows only the electrodes 8A-8B of the third electrode group 8, it is preferable that the other electrodes are also connected to the electrocardiograph 70. The third electrode group 8 and the electrocardiograph 70 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. By connecting the third electrode group 8 and the electrocardiograph 70 without a switch element or a resistor, the intracardiac potential can be measured with high accuracy.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] A conductor (lead wire) is connected to each electrode of the electrode unit 5. For example, one end of the conductor disposed in the lumen of the resin tube constituting the catheter 2 is joined to the inner circumferential surface of the electrode through a side hole provided in the outer circumferential surface of the resin tube. The other end of the conductor is preferably connected to a predetermined connector of the defibrillation electrical device 10 described below.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] As shown in FIGS. 1-2 and 4, the system 1 includes a power supply 13 that applies a voltage to the electrode unit 5 and includes one or more built-in capacitors 14. 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 one or more capacitors that charge the applied voltage. For example, it is preferable that a charging switch 63, which is preferably provided, be turned on to apply a predetermined applied voltage to the capacitor and charge it. In FIG. 2, the power supply 13 is connected to an output circuit 30.

[0040] 4 , the output circuit 30 includes a first switch element 31 and a second switch element 32 connected in parallel to each other, a third switch element 33 and a fourth switch element 34 connected in parallel to each other, a fifth switch element 35 and a sixth switch element 36 connected in parallel to each other, and a seventh switch element 37 and an eighth switch element 38 connected in parallel to each other. One end of the first switch element 31 is connected to the anode side of the capacitor 14 without any other switch element, and the other end is connected to the first most distal electrode 6A without any other switch element. One end of the second switch element 32 is connected to the cathode side of the capacitor 14 without any other switch element, and the other end is connected to the first most distal electrode 6A without any other switch element. One end of the third switch element 33 is connected to the anode side of the capacitor 14 without any other switch element, and the other end is connected to the first most proximal electrode 6B without any other switch element. One end of the fourth switch element 34 is connected to the cathode side of the capacitor 14 without any other switch elements, and the other end is connected to the first-most proximal electrode 6B without any other switch elements. One end of the fifth switch element 35 is connected to the anode side of the capacitor 14 without any other switch elements, and the other end is connected to the second-most distal electrode 7A without any other switch elements. One end of the sixth switch element 36 is connected to the cathode side of the capacitor 14 without any other switch elements, and the other end is connected to the second-most distal electrode 7A without any other switch elements. One end of the seventh switch element 37 is connected to the anode side of the capacitor 14 without any other switch elements, and the other end is connected to the second-most proximal electrode 7B without any other switch elements. One end of the eighth switch element 38 is connected to the cathode side of the capacitor 14 without any other switch elements, and the other end is connected to the second-most proximal electrode 7B without any other switch elements. By appropriately switching the first switch element 31 to the eighth switch element 38 ON and OFF, it is possible to apply a voltage and measure an intracardiac potential by outputting a DC voltage from the power supply 13 to each electrode.The defibrillation catheter system 1 does not include a conventional polarity-switching switch for energizing the electrical current, which is provided in the connection path between the power-side switch for mode switching and the capacitor 14. However, even without the polarity-switching switch, the polarity of the energizing electrical current can be switched by appropriately switching the first switch element 31 through the eighth switch element 38 ON and OFF. This allows for quick circuit switching after R-wave detection, thereby shortening the time from R-wave detection to voltage application. This prevents voltage application during the absolute refractory period, further enhancing the safety of the procedure. Furthermore, because the system 1 does not require a conventional polarity-switching switch element, the electrical circuitry of the system 1 can be configured compactly.

[0041] In the output circuit 30, two switch elements are connected to one electrode, with one of the two switch elements connected to the anode side of the capacitor 14 and the other connected to the cathode side. The first switch element 31, the third switch element 33, the fifth switch element 35, and the seventh switch element 37 may be directly connected to the anode of the capacitor 14, or the conductors connected to these switch elements may be connected to a first wiring connection portion (not shown), and another conductor extending from the first wiring connection portion may be directly connected to the anode of the capacitor 14. Similarly, the second switch element 32, the fourth switch element 34, the sixth switch element 36, and the eighth switch element 38 may be directly connected to the cathode of the capacitor 14, or the conductors connected to these switch elements may be connected to a second wiring connection portion (not shown), and another conductor extending from the second wiring connection portion may be directly connected to the cathode of the capacitor 14.

[0042] The connection of each terminal of the first switch element 31 to the eighth switch element 38 to the capacitor 14 or the electrode includes a configuration in which the terminal is connected to the capacitor 14 or the electrode only by a conductor, and a configuration in which the terminal is connected to the capacitor 14 or the electrode by a conductive member other than the switch element, such as a conductor or a connector.

[0043] The plurality of switch elements included in the output circuit 30 are connected in parallel to each other, so that the plurality of electrodes can be electrically separated, and voltage can be applied independently to each electrode.

[0044] Although FIG. 4 shows an example in which the output circuit 30 has eight switch elements, it is preferable that the number of switch elements included in the output circuit 30 is equal to (the number of electrodes used for voltage application × 2).

[0045] It is preferable that a high voltage is applied to the anode of the capacitor 14, and a lower voltage than that of the anode is applied to the cathode of the capacitor 14. The potential difference between the electrodes of the capacitor 14 is, for example, 600V.

[0046] The first switch element 31 to the eighth switch element 38 are switch elements that are independent of one another. These switch elements can be relay switches or semiconductor switches. Examples of semiconductor switch elements include IGBTs, MOSFETs, thyristors, elements using SiC semiconductors, and elements using GaN semiconductors.

[0047] Although different types of switches may be used as the multiple switch elements included in the output circuit 30, it is preferable to use the same type of switches. By using the same type of switches, the control of the system 1 can be simplified.

[0048] The multiple switch elements of the output circuit 30 may each be a single-pole, single-throw type or a multi-pole, single-throw type. If the switch is a single-pole, single-throw type, each switch can be operated individually, making it easier to apply voltage only to specific electrodes. If the switch is a multi-pole, single-throw type, multiple switches can be operated in conjunction with one operation, making it possible to improve the accuracy of the timing at which voltage is applied to each electrode.

[0049] As shown in FIGS. 1 and 2 , the system 1 may include an electrocardiograph switch unit 40 disposed in a connection path between the power supply 13 and an electrocardiograph connection unit 15 (described later) and connected to the electrode unit 5. The electrocardiograph switch unit 40 is disposed closer to the electrocardiograph connection unit 15 than the output circuit 30. The electrocardiograph switch unit 40 preferably includes a plurality of switch elements. For example, the electrocardiograph switch unit 40 may include a first electrocardiograph switch element 41 connected to the first most distal electrode 6A, a second electrocardiograph switch element 42 connected to the first most proximal electrode 6B, a third electrocardiograph switch element 43 connected to the second most distal electrode 7A, and a fourth electrocardiograph switch element 44 connected to the second most proximal electrode 7B. As shown in FIG. 2 , the electrocardiograph switch unit 40 and the electrocardiograph 70 are preferably connected via the electrocardiograph connection unit 15. Since the electrocardiograph side switch section 40 has switch elements connected to each electrode, by appropriately combining the ON / OFF of these switches with the ON / OFF of the switch elements of the output circuit 30, it is possible to apply voltage and measure intracardiac potentials by outputting a DC voltage from the power supply 13 to each electrode.

[0050] Although FIG. 4 shows an example in which the electrocardiograph-side switch section 40 has four switch elements, it is preferable that the number of switch elements included in the electrocardiograph-side switch section 40 is equal to the number of electrodes used for voltage application.

[0051] It is preferable that the multiple switch elements of the electrocardiograph switch section 40 are connected in parallel with each other, which allows the multiple electrodes to be electrically isolated, so that the intracardiac potential can be measured independently at each electrode.

[0052] The first electrocardiograph-side switch element 41 to the fourth electrocardiograph-side switch element 44 are switch elements independent of each other. These switch elements may be relay switches or semiconductor switches. Examples of semiconductor switch elements include IGBTs, MOSFETs, thyristors, elements using SiC semiconductors, and elements using GaN semiconductors.

[0053] The plurality of switch elements included in the electrocardiograph-side switch section 40 may each be of a single-pole single-throw type or a multi-pole single-throw type.

[0054] The switch elements of the electrocardiograph-side switch section 40 may be of different types, but preferably use the same type of switch. The switch elements of the output circuit 30 and the switch elements of the electrocardiograph-side switch section 40 may be of different types, but preferably use the same type of switch. Using the same type of switch can simplify the control of the system 1.

[0055] The switch elements of the output circuit 30 and the switch section 40 on the electrocardiograph side refer to switch elements mounted on the electronic circuit board, and are distinguished from operating switches such as push button switches and lever switches that are operated by the user to switch between ON and OFF.

[0056] The system 1 may include a switching unit 50 including an output circuit 30 and an electrocardiograph-side switch unit 40. In the switching unit 50 shown in FIG. 2 , the switch elements of the output circuit 30 are connected to the electrodes and the power supply 13 on a side closer to the power supply 13 than the electrocardiograph-side switch unit 40, and the switch elements of the electrocardiograph-side switch unit 40 are connected to the electrodes and the power supply 13 on a side closer to the electrocardiograph than the output circuit 30. The switching unit 50 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 electrocardiographic 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 50 preferably switches from the first mode to the second mode and from the second mode to the first mode. The switching unit 50 preferably switches modes based on an electrocardiographic signal input from an input unit 22 (described later).

[0057] In the first mode (cardiac potential measurement mode) of the switching unit 50, it is preferable that the switch element of the output circuit 30 is OFF and the switch element of the electrocardiograph-side switch unit 40 is ON. This allows electrocardiographic signals from the electrode unit 5 to be measured. In addition, in the second mode (defibrillation mode) of the switching unit 50, it is preferable that the switch element of the output circuit 30 is ON and the switch element of the electrocardiograph-side switch unit 40 is OFF. This allows defibrillation to be performed by outputting a DC voltage from the power supply 13 to each electrode while preventing a large current from accidentally flowing from the power supply 13 to the electrocardiograph 70 side.

[0058] The system 1 preferably includes a control unit 20 that controls the ON / OFF of switch elements included in the output circuit 30. The control unit 20 is preferably connected to the output circuit 30. This allows the control unit 20 to control each switch element included in the output circuit 30, thereby enabling a 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 included in the output circuit 30 to be controlled based on an electrocardiogram signal input from the input unit 22.

[0059] The control unit 20 is preferably connected to the electrocardiograph-side switch unit 40. This allows the control unit 20 to also control the ON / OFF of the switch elements of the electrocardiograph-side switch unit 40.

[0060] To avoid complicating the drawing, in FIG. 2 , the control unit 20 is connected to the output circuit 30, and the control unit 20 is connected to the electrocardiograph-side switch unit 40; however, it is preferable that the control unit 20 is connected to each of the switch elements 31 to 38 of the output circuit 30, and it is also preferable that the control unit 20 is connected to the switch elements 41 to 44 of the electrocardiograph-side switch unit 40.

[0061] 2 , the system 1 preferably includes a signal generating unit 21 that generates a first signal that permits application of a voltage to the electrode unit 5. After the signal generating unit 21 generates the first signal, the control unit 20 preferably controls the ON / OFF of the switch elements of the output circuit 30 so that at least one switch element connected to the cathode side of the capacitor 14 is turned ON and then at least one switch element connected to the anode side of the capacitor 14 is turned ON. Generally, a high voltage is applied to the anode of the capacitor 14, and a lower voltage than that applied to the anode is applied to the cathode of the capacitor 14. Therefore, by switching the switch elements ON / OFF in this order, the switch elements connected to the cathode side and the like are protected and the safety of the circuit is enhanced.

[0062] The signal generating unit 21 is preferably connected directly or indirectly to the power supply 13 .

[0063] The signal generating unit 21 may be connected to the control unit 20 or may be provided within the control unit 20 .

[0064] The first signal generated by the signal generating unit 21 is a signal that permits application of a voltage, but the signal generating unit 21 may also generate permission signals other than the first signal, such as a signal that permits charging the power source 13, a signal that permits generation of a pulse voltage, and a signal that permits each switch element to be switched on or off. At least one of these permission signals may be generated. In another aspect, some of these permission signals may be generated by operating the operation unit, etc.

[0065] The signal generating unit 21 may further generate a second signal indicating the end of application of voltage to the electrode unit 5. In this case, after the second signal is generated from the signal generating unit 21, it is preferable that the control unit 20 controls the ON / OFF of the switch elements of the output circuit 30 so that at least one switch element connected to the anode side of the capacitor 14 is turned OFF and then at least one switch element connected to the cathode side of the capacitor 14 is turned OFF. As described above, a high voltage is likely to be applied to the anode of the capacitor 14, and a low voltage is likely to be applied to the cathode side. Therefore, by switching the switch elements ON / OFF in this order, the switch elements connected to the cathode side and the like are protected and the safety of the circuit is enhanced.

[0066] It is preferable that the difference in the time when at least two or more of the first switch element 31, the third switch element 33, the fifth switch element 35, and the seventh switch element 37 are turned ON be within 10 μs. In this way, by setting the time when the switch element connected to the anode side of capacitor 14, to which a high voltage is generally applied, is turned ON to be short, the timing when the switch element is turned ON is less likely to be off, so that an appropriate amount of energy can be applied to the heart, thereby improving safety.

[0067] The difference in the time when at least two or more of the first switch element 31, the third switch element 33, the fifth switch element 35, and the seventh switch element 37 are turned ON is more preferably within 9 μs, even more preferably within 8 μs, and even more preferably within 7 μs. Furthermore, the difference in the time when at least two or more of the first switch element 31, the third switch element 33, the fifth switch element 35, and the seventh switch element 37 are turned ON may be more than 0 μs, and is also allowed to be 1 μs or more, 2 μs or more, or 3 μs or more.

[0068] The system 1 may have a component connection section for connecting the defibrillation electrical device 10 to a component other than the defibrillation electrical device 10, such as an electrocardiograph 70. For example, as shown in FIG. 2, the system 1 may have an electrocardiograph connection section 15 connected to the electrocardiograph 70. It is more preferable that the electrocardiograph connection section 15 be provided in the defibrillation electrical device 10. In FIG. 2, the switching section 50 and the electrocardiograph 70 are connected via the electrocardiograph connection section 15. Also, in FIG. 2, the electrocardiograph 70 and the switching section 50 are connected via resistors 38A to 38D (described below) and conductors, but some or all of the wired connections may be replaced with wireless connections.

[0069] The system 1 may further include a member connection section connected to the electrode section 5 of the catheter 20. For example, as shown in FIG. 2, the system 1 may include an electrode connection section 16 connected to the electrode section 5. The electrode connection section 16 is preferably connected to the electrodes of the first electrode group 6 and the electrodes of the second electrode group 7. The system 1 may also include a second electrocardiograph connection section 17 connected to the electrocardiograph 70 and a second electrode connection section 18 connected to the electrodes of the third electrode group 8. In FIG. 2, within the defibrillation electrical device 10, the electrocardiograph connection section 15 and the electrode connection section 16 are connected to each other via a switching section 50, resistors 38A to 38D, and conductors, and the second electrocardiograph connection section 17 and the second electrode connection section 18 are connected to each other via conductors.

[0070] The electrocardiograph connection portion 15, the electrode connection portion 16, the second electrocardiograph connection portion 17, and the second electrode connection portion 18 are preferably terminals for connection, and for example, connectors can be used. Examples of connectors include a concave connector and a convex connector. These may be part of the circuit constituting the control portion 20, or may be terminals physically connected to the conductors connected to the electrocardiograph 70 or the electrode portion 5, or may be part of a wireless communication device that receives electrocardiographic signals. Furthermore, when connecting components together, wired connections using conductors can be partially or entirely replaced with wireless connections.

[0071] When the system 1 includes a control unit 20 that controls the ON / OFF of the switch element of the output circuit 30 and a signal generating unit 21 that generates a first signal permitting application of a voltage to the electrode unit 5, it is preferable that, after generation of the first signal from the signal generating unit 21, the control unit 20 controls the ON / OFF of the switch element of the output circuit 30 so that, after the first signal is generated from the signal generating unit 21, a current flows from the first most distal electrode 6A to the second most proximal electrode 7B, and from the first most proximal electrode 6B to the second most distal electrode 7A, and then a current flows from the second most proximal electrode 7B to the first most distal electrode 6A, and from the second most distal electrode 7A to the first most proximal electrode 6B. The current flows from the first most distal electrode 6A to the second most proximal electrode 7B, and from the first most proximal electrode 6B to the second most distal electrode 7A, thereby applying a first phase wave of a biphasic energization waveform. Furthermore, by allowing a current to flow from the second most proximal electrode 7B to the first most distal electrode 6A, and also from the second most distal electrode 7A to the first most proximal electrode 6B, a second phase wave (a wave of opposite polarity to the first phase wave) of a biphasic electrical current waveform can be passed.

[0072] As shown in Figures 4 to 7, after the signal generating unit 21 generates the first signal, the control unit 20 preferably controls the ON / OFF of the switch elements of the output circuit 30 in the following order (i) to (iv). This allows the first phase wave of the biphasic conduction wave to be conducted while ensuring the safety of the circuit. (i) The sixth switch element 36 ON and the eighth switch element 38 ON (Figure 4), (ii) The first switch element 31 ON and the third switch element 33 ON (Figure 5), (iii) The first switch element 31 OFF and the third switch element 33 OFF (Figure 6), and (iv) The sixth switch element 36 OFF and the eighth switch element 38 OFF (Figure 7).

[0073] In the above (i), the eighth switch element 38 may be turned ON after the sixth switch element 36 is turned ON, or the sixth switch element 36 may be turned ON after the eighth switch element 38 is turned ON, or the sixth switch element 36 and the eighth switch element 38 may be turned ON simultaneously.

[0074] In the above (ii), the third switch element 33 may be turned ON after the first switch element 31 is turned ON, or the first switch element 31 may be turned ON after the third switch element 33 is turned ON, or the first switch element 31 and the third switch element 33 may be turned ON simultaneously.

[0075] In the above (iii), the third switch element 33 may be turned OFF after the first switch element 31 is turned OFF, or the first switch element 31 may be turned OFF after the third switch element 33 is turned OFF, or the first switch element 31 and the third switch element 33 may be turned OFF simultaneously.

[0076] In the above (iv), the eighth switch element 38 may be turned OFF after the sixth switch element 36 is turned OFF, or the sixth switch element 36 may be turned OFF after the eighth switch element 38 is turned OFF, or the sixth switch element 36 and the eighth switch element 38 may be turned OFF simultaneously.

[0077] As shown in Figures 8 to 11, after the signal generating unit 21 generates the first signal, the control unit 20 preferably controls the ON / OFF of the switch elements of the output circuit 30 in the following order (v) to (viii). This allows the second phase wave of the biphasic conduction wave to be conducted while ensuring the safety of the circuit. (v) The second switch element 32 ON and the fourth switch element 34 ON (Figure 8) (vi) The fifth switch element 35 ON and the seventh switch element 37 ON (Figure 9) (vii) The fifth switch element 35 OFF and the seventh switch element 37 OFF (Figure 10) (viii) The second switch element 32 OFF and the fourth switch element 34 OFF (Figure 11).

[0078] In the above (v), the fourth switch element 34 may be turned ON after the second switch element 32 is turned ON, or the second switch element 32 may be turned ON after the fourth switch element 34 is turned ON, or the second switch element 32 and the fourth switch element 34 may be turned ON simultaneously.

[0079] In the above (vi), the seventh switch element 37 may be turned ON after the fifth switch element 35 is turned ON, or the fifth switch element 35 may be turned ON after the seventh switch element 37 is turned ON, or the fifth switch element 35 and the seventh switch element 37 may be turned ON simultaneously.

[0080] In the above (vii), the seventh switch element 37 may be turned OFF after the fifth switch element 35 is turned OFF, or the fifth switch element 35 may be turned OFF after the seventh switch element 37 is turned OFF, or the fifth switch element 35 and the seventh switch element 37 may be turned OFF simultaneously.

[0081] In the above (viii), the fourth switch element 34 may be turned OFF after the second switch element 32 is turned OFF, or the second switch element 32 may be turned OFF after the fourth switch element 34 is turned OFF, or the second switch element 32 and the fourth switch element 34 may be turned OFF simultaneously.

[0082] 2, the system 1 preferably further includes a current detection circuit 24 connected to the connection path between the power supply 13 and the output circuit 30, for detecting whether the current flowing from the power supply 13 to the output circuit 30 exceeds a predetermined value. This makes it possible to detect an unacceptable current flowing to the human body or the electrocardiograph through the electrode unit 5, thereby enhancing the safety of the system 1. A known current sensor or the like can be used as the current detection circuit 24, and examples thereof include a resistance detection type current sensor and a magnetic field detection type current sensor.

[0083] Although FIGS. 4 to 11 show examples in which the power supply 13 has only one capacitor 14, the power supply 13 may have multiple capacitors 14. One capacitor 14 may be connected to one electrode. The power supply 13 may have the same number of capacitors 14 as the total number of electrodes in the first electrode group 6 and the second electrode group 7. For example, in FIG. 12, the power supply 13 has a first capacitor 14A connected to the first most distal electrode 6A, a second capacitor 14B connected to the first most proximal electrode 6B, a third capacitor 14C connected to the second most distal electrode 7A, and a fourth capacitor 14D connected to the second most proximal electrode 7B. By providing a capacitor 14 for each electrode in this manner, it is possible to apply different values ​​of electric potential to each electrode.

[0084] Conventionally, a defibrillation catheter system 1 used for applying voltage is configured to apply a fixed DC voltage, such as 600 V, between two electrodes. However, because the catheter 2 has multiple electrodes arranged along its longitudinal axis, the distance between the two electrodes that are energized varies depending on the position of each electrode, which can result in a change in resistance. For example, the distance between the most distal electrode of the first electrode group 6 and the most proximal electrode of the second electrode group 7 differs from the distance between the most proximal electrode of the first electrode group 6 and the most distal electrode of the second electrode group 7, which can result in a difference in resistance between the electrodes. As a result, it can be difficult to apply a uniform voltage (600 V in the above example) between each electrode. By providing a capacitor 14 for each electrode as shown in FIG. 12 , it is possible to apply different potentials to each electrode, which makes it easier to eliminate potential differences that occur when the two energized electrodes are far from each other and when they are close to each other, making it easier to apply a uniform voltage throughout the catheter 2.

[0085] 12, the power supply 13 preferably has a first capacitor 14A connected to the first most distal electrode 6A and a second capacitor 14B connected to the first most proximal electrode 6B, the second capacitor 14B having a smaller maximum amount of electricity stored therein than the first capacitor 14A. The more distal an electrode of the first electrode group 6 to which the capacitor 14 is connected is, the larger the capacitance of the capacitor 14 becomes, which makes it possible to impart higher energy to the electrode, and therefore makes it easier to eliminate the potential difference even when the distance between the two electrodes being energized is large.

[0086] The maximum amount of electricity (unit: C) stored in the first capacitor 14A may be 1.1 times or more, 1.30 times or more, 1.50 times or more, or may be 3.00 times or less, 2.80 times or less, 2.50 times or less, 2.00 times or less, etc., of the maximum amount of electricity stored in the second capacitor 14B.

[0087] The power supply 13 preferably has a third capacitor 14C connected to the second most distal electrode 7A, and a fourth capacitor 14D connected to the second most proximal electrode 7B, which has a larger maximum amount of electricity stored therein than the third capacitor 14C. The more distal an electrode of the second electrode group 7 to which the capacitor 14 is connected is, the larger the capacitance of the capacitor 14 becomes, making it possible to impart higher energy to the electrode, and thus making it easier to eliminate the potential difference even when the distance between the two electrodes being energized is large.

[0088] The maximum amount of electricity (unit: C) stored in the fourth capacitor 14D may be 1.1 times or more, 1.30 times or more, 1.50 times or more, or 3.00 times or less, 2.80 times or less, 2.50 times or less, 2.00 times or less, etc., the maximum amount of electricity stored in the third capacitor 14C.

[0089] Preferably, the electrodes included in the first electrode group 6 and the electrodes included in the second electrode group 7 are controlled to receive potentials of different polarities, and the first-most distal electrode 6A and the first-most proximal electrode 6B are controlled to receive potentials of the same polarity but different values. In this case, it is preferable that a voltage be applied between the first-most distal electrode 6A and the second-most proximal electrode 7B, and a voltage be applied between the first-most proximal electrode 6B and the second-most distal electrode 7A. Because the distance between the first-most distal electrode 6A and the second-most proximal electrode 7B is longer than the distance between the first-most proximal electrode 6B and the second-most distal electrode 7A, the resistance between the first-most distal electrode 6A and the second-most proximal electrode 7B may be higher than the resistance between the first-most proximal electrode 6B and the second-most distal electrode 7A. However, applying the potentials as described above makes it easier to eliminate the potential difference that occurs when the two energized electrodes are far from each other and when they are close to each other, making it easier to apply a uniform voltage throughout the catheter 2.

[0090] The system 1 preferably has one or more operation units for performing various operations such as turning on / off the electric device 10, setting the amount of applied energy, charging voltage, applying voltage, selecting the application electrode, etc. Known input means such as a push button switch or a lever can be used as the operation unit.

[0091] The system 1 may have a main power switch 61 for turning on and off the main power of the electrical device 10. Examples of the main power switch 61 include a push button switch, a slide switch, and a rocker switch. When the main power switch 61 is turned on, an intracardiac potential may be measured by the electrode portion 5 of the catheter 2. When the main power switch 61 is turned on, the system may enter a cardiac potential measurement mode.

[0092] The system 1 may have an applied energy setting switch 62 for setting the amount of applied energy. Examples of the applied energy setting switch 62 include a touch panel, a dial switch, and a push button switch.

[0093] The system 1 may have a charging switch 63 for instructing the start of energy charging. Examples of the charging switch 63 include a touch panel and a push button switch. When the charging switch 63 is turned on, it is preferable that the signal generating unit 21 generates a signal to instruct the power source 13 to start charging energy. Then, it is preferable that charging of the capacitor 14 preferably included in the power source 13 is started upon receiving the signal from the signal generating unit 21.

[0094] The system 1 may have an application execution switch 64 for instructing the start of voltage application. Examples of the application execution switch 64 include a touch panel, a push button switch, and the like. When the application execution switch 64 is turned on, it is preferable that the signal generating unit 21 generates a first signal that permits the application of voltage for defibrillation. This allows the user to operate the application execution switch 64 and apply voltage at the user's timing.

[0095] The system 1 may have an electrode selection switch 65 for selecting an electrode to which the voltage is to be applied. Examples of the electrode selection switch 65 include a touch panel and a push button switch.

[0096] At least one of the main power switch 61, the applied energy setting switch 62, the charging switch 63, the application execution switch 64, and the electrode selection switch 65 is preferably connected to the switching unit 50. At least one of the main power switch 61, the applied energy setting switch 62, the charging switch 63, the application execution switch 64, and the electrode selection switch 65 is preferably connected to the power source 13. At least one of the main power switch 61, the applied energy setting switch 62, the charging switch 63, the application execution switch 64, and the electrode selection switch 65 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 61, the applied energy setting switch 62, the charging switch 63, the application execution switch 64, and the electrode selection switch 65 is preferably provided in the electrical device 10.

[0097] 2, an impedance measuring unit 25 may be disposed in the connection path between the power supply 13 and the output circuit 30. The impedance measuring unit 25 preferably measures the impedance between the two electrodes of the electrode unit 5, or between the first electrode group 6 and the second electrode group 7. By measuring the impedance, it is possible to set an applied waveform suited to the patient.

[0098] It is preferable that, after the impedance measurement by the impedance measurement unit 25 is completed, the power supply 13 is controlled to apply a voltage to the electrode unit 5. For example, after the application execution switch 64 is input, the following may be performed in order: generation of a first signal from the signal generation unit 21; switching of each switch element by the switching unit 50 between ON and OFF; measurement of impedance by the impedance measurement unit 25; and application of a voltage to the electrode unit 5 by the power supply 13.

[0099] After the charging switch 63 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 64 is turned on.

[0100] A resistor may be disposed in the connection path between the electrode unit 5 and the electrocardiograph 70. For example, in FIG. 2 , electrode 6A of the first electrode group 6 is connected to the electrocardiograph 70 via resistor 56, electrode 6B of the first electrode group 6 is connected to the electrocardiograph 70 via resistor 57, electrode 7A of the second electrode group 7 is connected to the electrocardiograph 70 via resistor 58, and electrode 7B of the second electrode group 7 is connected to the electrocardiograph 70 via resistor 59. The resistors prevent the electrocardiograph 70 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 70 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 70 without distortion. The resistance may be 150 Ω or less, 100 Ω or less, 50 Ω or more, or 70 Ω or more.

[0101] 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.

[0102] 1 and 2, the system 1 is preferably connected to an electrocardiograph 70. The electrocardiograph 70 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).

[0103] The electrocardiograph 70 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 70, 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 70 may have an analog-to-digital conversion circuit (AD conversion circuit) that converts analog signals to digital signals. The AD conversion circuit may be connected downstream of the amplifier circuit or the filter circuit. The electrocardiograph 70 may have a display unit for displaying the electrocardiographic waveform. Examples of the display unit include a liquid crystal display. While known electrocardiographs 70 can be used, it is preferable that the electrocardiograph 70 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 70. Examples of the display device include a computer, an external monitor, a mobile phone, a smartphone, and a tablet terminal.

[0104] The electrocardiograph 70 may be connected to the power source 13. For example, the electrocardiograph 70 may be connected to the defibrillation electrical device 10 including the power source 13. When the electrocardiograph 70 is connected to the power source 13, an overvoltage protection circuit that protects the electrocardiograph 70 from overvoltage is preferably provided in the connection path between the power source 13 and the electrocardiograph 70. By providing the overvoltage protection circuit, it is possible to prevent damage to the electrocardiograph 70 due to application of overvoltage to the electrocardiograph 70. 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.

[0105] 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 and which is connected to an electrocardiograph 70. This allows each switch element 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.

[0106] For example, as shown in FIG. 2 , the system 1 preferably includes an R-wave detection unit 23 connected to the input unit 22 and configured to detect R-waves using an 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 ventricular muscle response. Therefore, voltage application is generally synchronized with R-waves. Therefore, detecting R-waves with the R-wave detection unit 23 can prevent stimulation of the heart outside the absolute refractory period. The R-wave detection unit 23 is preferably disposed in the control unit 20. The R-wave detection unit 23 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 R-wave detection unit 23. The R-wave detection unit 23 preferably detects R-wave peaks from the electrocardiographic signal. Furthermore, the R-wave detection unit 23 preferably detects at least one of P-wave peaks and Q-wave peaks from the electrocardiographic signal.

[0107] At least one of the functions of the system 1, for example, the functions of the control unit 20, the signal generating unit 21, the input unit 22, the R-wave detecting unit 23, the current detecting circuit 24, and the impedance measuring unit 25, 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).

[0108] 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 signal generating unit 21, the input unit 22, the R-wave detecting unit 23, the current detecting circuit 24, and the impedance measuring unit 25. 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.

[0109] This application claims the benefit of priority based on Japanese Patent Application No. 2024-54460, filed on March 28, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-54460, filed on March 28, 2024, are incorporated herein by reference.

[0110] 1: Defibrillation catheter system 2: Catheter 3: Distal tip 4: Handle 5: Electrode section 6: First electrode group 6A: First most distal electrode 6B: First most proximal electrode 7: Second electrode group 7A: Second most distal electrode 7B: Second most proximal electrode 8: Third electrode group 10: Defibrillation electrical device 13: Power supply 14: Capacitor 14A: First capacitor 14B: Second capacitor 14C: Third capacitor 14D: Fourth capacitor 20: Control section 21: Signal generating section 22: Input section 23: R wave detecting section 24: Current detecting circuit 25: Impedance measuring section 30: Output circuit 31: First switch element 32: Second switch element 33: Third switch element 34: Fourth switch element 35: Fifth switch element 36: Sixth switch element 37: Seventh switch element 38: Eighth switch element 40: Electrocardiograph side switch section 41 to 44: Electrocardiograph side switches 50: Switching section 56 to 59: Resistors 61: Main power switch 62: Applied energy setting switch 63: Charging switch 64: Application execution switch 65: Electrode selection switch 70: Electrocardiograph

Claims

1. A catheter having a longitudinal axis direction; an electrode section having a first electrode group disposed on the catheter and including a first most distal electrode and a first most proximal electrode arranged in order from the distal side; and a second electrode group disposed on the catheter proximal to the first electrode group and including a second most distal electrode and a second most proximal electrode arranged in order from the distal side; a power supply for applying a voltage to the electrode section, the power supply having one or more built-in capacitors; and an output circuit having first and second switch elements connected in parallel to each other, third and fourth switch elements connected in parallel to each other, fifth and sixth switch elements connected in parallel to each other, and seventh and eighth switch elements connected in parallel to each other, wherein one end of the first switch element is connected to the anode side of the capacitor without passing through any other switch elements, and the other end is connected to the first most distal electrode without passing through any other switch elements, one end of the second switch element is connected to the cathode side of the capacitor without any other switch elements, and the other end is connected to the first most distal electrode without any other switch elements; one end of the third switch element is connected to the anode side of the capacitor without any other switch elements, and the other end is connected to the first most proximal electrode without any other switch elements; one end of the fourth switch element is connected to the cathode side of the capacitor without any other switch elements, and the other end is connected to the first most proximal electrode without any other switch elements; one end of the fifth switch element is connected to the anode side of the capacitor without any other switch elements, and the other end is connected to the second most distal electrode without any other switch elements; one end of the sixth switch element is connected to the cathode side of the capacitor without any other switch elements, and the other end is connected to the second most distal electrode without any other switch elements; one end of the seventh switch element is connected to the anode side of the capacitor without any other switch element and the other end is connected to the second-most proximal electrode without any other switch element; and one end of the eighth switch element is connected to the cathode side of the capacitor without any other switch element and the other end is connected to the second-most proximal electrode without any other switch element.

2. The catheter system according to claim 1, further comprising a control unit that controls the ON / OFF of the switch elements of the output circuit, and a signal generating unit that generates a first signal that permits application of voltage to the electrode unit, and wherein, after generation of the first signal from the signal generating unit, the ON / OFF of the switch elements of the output circuit is controlled by the control unit so that at least one switch element connected to the cathode side of the capacitor is turned ON, and then at least one switch element connected to the anode side of the capacitor is turned ON.

3. A defibrillation catheter system as claimed in claim 2, wherein the signal generating unit further generates a second signal indicating the end of application of voltage to the electrode unit, and after the second signal is generated from the signal generating unit, the control unit controls the ON / OFF of the switch elements of the output circuit so that at least one switch element connected to the anode side of the capacitor is turned OFF and then at least one switch element connected to the cathode side of the capacitor is turned OFF.

4. A defibrillation catheter system as described in claim 1 or 2, wherein the difference in time when at least two of the first switch element, the third switch element, the fifth switch element, and the seventh switch element are turned ON is within 10 μs.

5. The catheter system according to claim 1 or 2, further comprising: a control unit that controls the ON / OFF of a switch element of the output circuit; and a signal generating unit that generates a first signal that permits application of a voltage to the electrode unit; and wherein, after generation of the first signal from the signal generating unit, the ON / OFF of the switch element of the output circuit is controlled by the control unit so that, after generation of the first signal from the signal generating unit, a current flows from the first most distal electrode to the second most proximal electrode, and from the first most proximal electrode to the second most distal electrode, and thereafter, a current flows from the second most proximal electrode to the first most distal electrode, and from the second most distal electrode to the first most proximal electrode.

6. The defibrillation catheter system according to claim 5, wherein after the first signal is generated from the signal generating unit, the control unit controls the ON / OFF of the switch elements of the output circuit in the following order (i) to (viii): (i) the sixth switch element ON and the eighth switch element ON, (ii) the first switch element ON and the third switch element ON, (iii) the first switch element OFF and the third switch element OFF, (iv) the sixth switch element OFF and the eighth switch element OFF, (v) the second switch element ON and the fourth switch element ON, (vi) the fifth switch element ON and the seventh switch element ON, (vii) the fifth switch element OFF and the seventh switch element OFF, and (viii) the second switch element OFF and the fourth switch element OFF.

7. A defibrillation catheter system according to claim 1 or 2, wherein the power source comprises a first capacitor connected to the first most distal electrode and a second capacitor connected to the first most proximal electrode and having a maximum amount of electricity stored therein smaller than that of the first capacitor.

8. A defibrillation catheter system according to claim 1 or 2, wherein the power source comprises a third capacitor connected to the second most distal electrode, and a fourth capacitor connected to the second most proximal electrode and having a maximum amount of electricity stored therein that is greater than that of the third capacitor.

9. A defibrillation catheter system according to claim 1 or 2, wherein the electrodes included in the first electrode group and the electrodes included in the second electrode group are controlled so that potentials of different polarities are applied to them, and the first most distal electrode and the first most proximal electrode are controlled so that potentials of the same polarity but different values ​​are applied to them.

10. A defibrillation catheter system as described in claim 1 or 2, further comprising a current detection circuit connected to the connection path between the power supply and the output circuit, for detecting whether the current flowing from the power supply to the output circuit exceeds a predetermined value.

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