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

Abstract

An intracardiac defibrillation catheter system (1) comprises: a power supply (13) that applies a voltage to an electrode portion (5) of a catheter (2); an input portion (22) to which an electrocardiographic signal is input; and a switching unit (30) that is connected to the power supply (13) and switches between a first mode, in which the power supply (13) and the electrode portion (5) are electrically disconnected, and a second mode, in which the power supply (13) and the electrode portion (5) are electrically connected. The electrode portion (5) is connected to the power supply (13) with the switching unit (30) therebetween and is controlled so that requirements 1 and 2 are satisfied.　(Requirement 1) After an R wave of the electrocardiographic signal is detected, the switching unit (30) switches the first mode to the second mode before the end of the detected R wave.　(Requirement 2) After requirement 1, the power supply (13) applies a voltage to the electrode portion (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 to prevent the ventricular muscle from reacting. If the heart is stimulated outside the absolute refractory period, the ventricular muscle may react, potentially resulting in ventricular fibrillation. For this reason, in defibrillation catheter systems, voltage is applied in synchronization with the R wave. Patent Document 1 discloses an example of a defibrillation catheter system. Patent Document 1 discloses that after determining whether an R wave has been acquired (after S5), switching elements 31 to 35 are controlled in a defibrillation process (S13), and pulse voltages of opposite polarities are applied to the cardiac cavity from the first electrode group 41 and the second electrode group 42 in the defibrillation process (S13).

[0004] Japanese Patent Application Laid-Open No. 2022-117198

[0005] In the system described in Patent Document 1, defibrillation is delivered within the absolute refractory period after R-wave detection, but to provide safer treatment, it is necessary to shorten the time until synchronization with the R-wave. The present invention was made in light of these circumstances, and its object is to provide an intracardiac defibrillation catheter system and a control method for an intracardiac defibrillation catheter system that can provide safer treatment by shortening the time from switching to a defibrillation mode until synchronization with the R-wave.

[0006] An intracardiac defibrillation catheter system according to an embodiment of the present invention that has been able to 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 in a distal portion of the catheter; a power source that applies a voltage to the electrode portion; an input portion to which an electrocardiogram signal is input; and a switching portion connected to the power source and switching between a first mode in which the power source and the electrode portion are electrically disconnected and a second mode in which the power source and the electrode portion are electrically connected, the electrode portion being connected to the power source via the switching portion, the intracardiac defibrillation catheter system being controlled to satisfy the following requirements 1 and 2: (Requirement 1) After detecting an R wave of the electrocardiogram signal, the switching portion switches from the first mode to the second mode before the end of the detected R wave. (Requirement 2) After requirement 1 is met, the power source applies a voltage to the electrode portion.

[0007] Furthermore, the intracardiac defibrillation catheter system according to the embodiment preferably satisfies any one of the following [2] to [7]. [2] The intracardiac defibrillation catheter system according to [1], wherein the switching unit switches the first mode to the second mode after detecting a peak of an R wave in the electrocardiogram signal in the requirement 1. [3] The intracardiac defibrillation catheter system according to [1], wherein the switching unit switches the first mode to the second mode after detecting a rising edge of an R wave in the electrocardiogram signal in the requirement 1. [4] The intracardiac defibrillation catheter system according to any one of [1] to [3], wherein the power source applies a voltage to the electrode unit before the end of an R wave that triggered the switching unit to switch the first mode to the second mode in the requirement 2. [5] The intracardiac defibrillation catheter system according to any one of [1] to [4], wherein the input unit is connected to an electrocardiograph, and the intracardiac defibrillation catheter system includes a detection unit connected to the input unit and configured to detect an R wave using the electrocardiogram signal from the electrocardiograph input to the input unit. [6] The intracardiac defibrillation catheter system according to any one of [1] to [5], further comprising a first connection unit connected to the electrocardiograph, the switching unit having a first switch arranged on the first connection unit side and a second switch arranged on the power supply side, the first switch and the second switch being independent of each other. [7] The intracardiac defibrillation catheter system according to any one of [1] to [6], further comprising a delay unit that delays the start timing of requirement 2 so that requirement 2 is started after a first predetermined time has elapsed after requirement 1 has ended.

[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: [8] A control method for an intracardiac defibrillation catheter system having: a catheter having a longitudinal axis direction, an electrode unit disposed in a distal portion of the catheter, a power source that applies a voltage to the electrode unit, an input unit to which an electrocardiogram signal is input, and a switching unit connected to the power source and switching between a first mode in which the power source and the electrode unit are electrically disconnected and a second mode in which the power source and the electrode unit are electrically connected, wherein the electrode unit is connected to the power source via the switching unit, the control method for an intracardiac defibrillation catheter system comprising: a step of detecting an R wave of the electrocardiogram signal, a step of the switching unit switching from the first mode to the second mode before the detected R wave ends, and a step of the power source applying a voltage to the electrode unit.

[0009] Furthermore, the control method for the intracardiac defibrillation catheter system according to the embodiment is preferably any one of the following [9] to

[11] .

[0010] [9] The control method for an intracardiac defibrillation catheter system according to [8], wherein the switching unit switches from the first mode to the second mode after detecting a peak of an R wave in the electrocardiogram signal.

[10] The control method for an intracardiac defibrillation catheter system according to [8], wherein the switching unit switches from the first mode to the second mode after detecting a rising edge of an R wave in the electrocardiogram signal.

[11] The control method for an intracardiac defibrillation catheter system according to any one of [8] to

[10] , wherein the power source applies a voltage to the electrode unit before the end of the R wave that triggered the switching unit to switch from the first mode to the second mode.

[0011] According to the above-described intracardiac defibrillation catheter system and the control method for the intracardiac defibrillation catheter system, after an R wave of an electrocardiogram signal is detected, the mode is switched and voltage is applied to the electrode portion before the end of the detected R wave, thereby shortening the time from mode switching to voltage application and enabling safer treatment.

[0012] Fig. 1 is a schematic diagram of an intracardiac defibrillation catheter system according to one embodiment of the present invention; Fig. 2 is a circuit diagram of an intracardiac defibrillation catheter system according to one embodiment of the present invention; Fig. 3 is a diagram showing an example of an electrocardiogram waveform obtained from an electrocardiogram signal; Fig. 4 is a flowchart showing a control method for an intracardiac defibrillation catheter system according to one embodiment of the present invention; Fig. 5 is a flowchart showing a control method for an intracardiac defibrillation catheter system according to another embodiment of the present invention;

[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 direction, an electrode unit disposed in a distal portion of the catheter, a power source that applies a voltage to the electrode unit, an input unit to which an electrocardiogram signal is input, and a switching unit connected to the power source and switching between a first mode in which the power source and the electrode unit are electrically disconnected and a second mode in which the power source and the electrode unit are electrically connected, the electrode unit being connected to the power source via the switching unit, and the intracardiac defibrillation catheter system being controlled to satisfy the following requirements 1 and 2: (Requirement 1) After detecting an R wave of the electrocardiogram signal, the switching unit switches from the first mode to the second mode before the end of the detected R wave. (Requirement 2) After requirement 1, the power source applies a voltage to the electrode unit.

[0015] According to the above-described intracardiac defibrillation catheter system, after detecting the R wave of an electrocardiogram signal as required in Requirement 1, the mode is switched and voltage is applied to the electrode portion before the end of the detected R wave as required in Requirement 2. This shortens the time from mode switching to voltage application, enabling safer treatment.

[0016] An intracardiac defibrillation catheter system according to one embodiment of the present invention will be described with reference to Figures 1 to 3. 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 diagram showing an example of an electrocardiographic waveform obtained from an electrocardiographic signal. Hereinafter, the intracardiac defibrillation catheter system may be simply referred to as a system. System 1 includes a catheter 2, an electrode unit 5, a power supply 13, an input unit 22, and a switching unit 30.

[0017] The system also 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 having a power source 13 that applies a voltage to the electrode unit 5, an input unit 22 to which an electrocardiogram signal is input, and a switching unit 30 that switches between a first mode in which the power source 13 and the electrode unit 5 are electrically disconnected and a second mode in which the power source 13 and the electrode unit 5 are electrically connected. In this case, the electrode unit 5 is connected to the power source 13 via the switching unit 30, and the intracardiac defibrillation catheter system 1 is preferably controlled to satisfy the following requirements 1 and 2: (Requirement 1) After detecting an R wave of an electrocardiogram signal, the switching unit 30 switches from the first mode to the second mode before the end of the detected R wave. (Requirement 2) After requirement 1, 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.

[0018] 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.

[0019] 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 50 or the like based on the measured electrocardiogram signal. Therefore, the electrocardiogram signal measured by the electrode unit 5 is input to an input unit 22, which will be described later. Furthermore, it is preferable that the electrocardiogram signal measured by the electrode unit 5 be captured by the electrocardiograph 50.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 improves the ease of insertion of the catheter 2 into the body.

[0042] 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.

[0043] 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.

[0044] As shown in FIGS. 1 and 2, the system 1 has a power supply 13 that applies a voltage to the electrode unit 5. The power supply 13 preferably has a capacitor. The power supply 13 preferably has a power supply circuit for generating a DC voltage. The power supply circuit may have, 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 a switching unit 30.

[0045] As shown in FIGS. 1 and 2 , the system 1 includes an input unit 22 to which an electrocardiographic signal is input. Based on the electrocardiographic signal input from the input unit 22, a switching unit 30 switches from a first mode (cardiac potential measurement mode) to a second mode (defibrillation mode), or vice versa. The input unit 22 is preferably connected to an electrocardiograph 50. 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 an electrocardiographic signal (electrocardiographic waveform) based on the electrocardiographic potential, 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.

[0046] 2 , the system 1 is connected to a power source 13 and includes a switching unit 30 that switches between a first mode in which the power source 13 and the electrode unit 5 are electrically disconnected and a second mode in which the power source 13 and the electrode unit 5 are electrically connected. The electrode unit 5 is connected to the power source 13 via the switching unit 30. Switching the switching unit 30 to the second mode enables voltage application by outputting a DC voltage from the power source 13 to the electrode unit 5, and switching the switching unit 30 to the first mode enables measurement of an intracardiac potential by the electrode unit 5.

[0047] The switching unit 30 preferably has one or more switches. The switches included in the switching unit 30 may be of a single-pole single-throw type or a multi-pole single-throw type, but are preferably of a multi-pole single-throw type.

[0048] For example, a relay switch or a semiconductor switch can be used as the switching unit 30. 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] The system 1 is controlled as described in the following requirements 1 and 2. (Requirement 1) After detecting an R wave of an electrocardiogram signal, the switching unit 30 switches from the first mode to the second mode before the detected R wave ends. (Requirement 2) After requirement 1, the power supply 13 applies a voltage to the electrode unit 5.

[0050] According to the control method of the above-described system 1, after detecting the R wave of the electrocardiogram signal, the mode is switched before the end of the detected R wave, and then voltage is applied to the electrode portion 5. This shortens the time from mode switching to voltage application, enabling safer treatment.

[0051] As shown in Figures 1 and 2, the system 1 is preferably connected to an electrocardiograph 50. The electrocardiograph 50 is a device that generates electrocardiographic waveforms (electrocardiogram waveforms) based on electrocardiographic signals (also called electrocardiogram signals or ECG signals) that measure 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 shown in Figure 3 represents potential (e.g., in mV), and the horizontal axis represents time (e.g., in seconds). While a known electrocardiograph 50 can be used, it is preferable that the electrocardiograph 50 generates electrocardiographic waveforms based on intracardiac potentials measured by the electrode unit 5 of the catheter 2.

[0052] 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 can 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 into a digital signal. The AD conversion circuit may be connected downstream of the amplifier circuit or downstream of the filter circuit.

[0053] The electrocardiograph 50 may have a display unit for displaying an electrocardiographic waveform. Examples of the display unit include a liquid crystal display (LCD). The display unit of the electrocardiograph 50 may display only an electrocardiographic waveform 60 as shown in FIG. 3 , or may display both the electrocardiographic waveform 60 and a differential waveform (not shown). In the electrocardiographic waveform 60, the first wave to appear and appearing upward relative to baseline B is the P wave. The P wave indicates the excitation process of the atrium. The wave that appears after the P wave and appears downward relative to baseline B is the Q wave. The wave that appears after the Q wave and appears upward relative to baseline B is the R wave. The peak height of the R wave is the greatest compared to the other waves. The wave that appears after the R wave and appears downward relative to baseline B is the S wave. The portion from the beginning of the Q wave to the end of the S wave is called the QRS wave, and indicates excitation of the left and right ventricular muscles. 2 shows a peak position 61P of a P wave, a peak position 61Q of a Q wave, a peak position 61R of an R wave, and a peak position 61S of an S wave. The peak positions of the P waves, Q waves, R waves, and S waves may be distinguished by setting thresholds for the signal strength (height), width, slope (differential waveform) of the electrocardiogram waveform, and the like, and the peak positions of each wave may be determined. Alternatively, focusing on the R waves, each wave may be distinguished in a section estimated from the interval at which the R waves are detected, and the peak positions of each wave may be determined.

[0054] 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.

[0055] In requirement 1, detection of an R wave of an electrocardiographic signal can be performed by analyzing the electrocardiographic signal input from the input unit 22. Specifically, as shown in FIG. 2 , it is preferable that the input unit 22 is connected to an electrocardiograph 50, and the system 1 includes a detector 27 connected to the input unit 22 and configured to detect an R wave using the electrocardiographic signal input from the electrocardiograph 50. This allows the detector 27 to analyze an electrocardiographic waveform based on the electrocardiographic signal measured by the electrocardiograph 50, thereby detecting an R wave. In treating atrial fibrillation, a voltage must be applied to the heart during the absolute refractory period to prevent the ventricular muscle from responding. Therefore, the voltage is generally applied in synchronization with the R wave. Therefore, detecting the R wave with the detector 27 can prevent stimulation of the heart outside the absolute refractory period.

[0056] The detector 27 is preferably disposed in the controller 20. The detector 27 may be part of a circuit constituting the controller 20, an input terminal physically connected to a device that measures the electrocardiogram signal, or part of a wireless communication device that receives the electrocardiogram signal. The defibrillator 10 of the system 1 preferably includes the detector 27.

[0057] The detector 27 is preferably capable of detecting at least one of the peak of an R wave, the rising edge of an R wave, and the falling edge of an R wave. The detector 27 is also preferably capable of detecting at least one of the peak of a P wave, the rising edge of a P wave, and the falling edge of a P wave. The detector 27 is also preferably capable of detecting at least one of the peak of a Q wave, the rising edge of a Q wave, and the falling edge of a Q wave. Additionally, the detector 27 is preferably capable of detecting information necessary for analyzing an electrocardiogram waveform.

[0058] The electrocardiograph 50 may be connected to the power supply 13. For example, the electrocardiograph 50 may be connected to the defibrillation electrical device 10 including the power supply 13. When the electrocardiograph 50 is connected to the power supply 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 supply 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.

[0059] In requirement 1, it is preferable that the switching unit 30 switches from the first mode to the second mode after detecting the peak of the R wave of the electrocardiogram signal. This allows the power supply 13 to quickly apply voltage to the electrode unit 5 when the detection unit 27 detects the peak 61R of the R wave, thereby shortening the time from switching to the second mode, in which defibrillation can be performed, until voltage is applied to the electrode unit 5 to perform defibrillation, enabling safer treatment.

[0060] The timing at which the switching unit 30 switches from the first mode to the second mode is preferably after detecting the P-wave peak 61P and after detecting the R-wave peak 61R. In another embodiment, the timing at which the switching unit 30 switches from the first mode to the second mode may be after detecting the Q-wave peak 61Q and after detecting the R-wave peak 61R. In yet another embodiment, the timing at which the switching unit 30 switches from the first mode to the second mode may be after detecting the P-wave peak 61P, the Q-wave peak 61Q, and then the R-wave peak 61R. In this way, by combining the P-wave peak 61P and / or the Q-wave peak 61Q with the R-wave peak 61R, the possibility of false detection can be reduced, enabling safer treatment.

[0061] It is preferable to use deep learning using AI (Artificial Intelligence) to detect the P wave peak 61P, the Q wave peak 61Q, and the R wave peak 61R. For example, a plurality of electrocardiogram waveforms acquired over a certain period of time may be learned, characteristics of the patient's P waves, Q waves, R waves, etc. may be estimated, and the P waves, Q waves, R waves, etc. may be detected using the estimated parameters.

[0062] The detection unit 27 may detect the rising edge and / or falling edge of the R wave using a differential waveform generated from the electrocardiographic waveform. Regarding requirement 1, the switching unit 30 may switch from the first mode to the second mode after detecting the rising edge of the R wave of the electrocardiographic signal. Regarding requirement 1, the switching unit 30 may switch from the first mode to the second mode between the rising edge of the R wave of the electrocardiographic signal and the peak of the R wave. For example, regarding requirement 1, the switching unit 30 may switch from the first mode to the second mode after the peak value of the differential waveform generated from the electrocardiographic waveform becomes equal to or greater than a positive constant C1. To use the differential waveform to detect the R wave of the electrocardiographic signal, the electrocardiograph 50 may have a differentiation circuit. The constant C1 may have a different value depending on the type of differentiation circuit, etc. The constant C1 may be any value greater than the vertical axis value of the baseline of the differential waveform, and may be set to, for example, equal to or greater than half the peak value of the differential waveform.

[0063] In requirement 1, the switching unit 30 may switch from the first mode to the second mode after the peak of the R wave of the electrocardiogram signal has passed and before the end of the R wave. Specifically, in requirement 1, the switching unit 30 may switch from the first mode to the second mode after the differential value (value on the vertical axis of the differential waveform) of the differential waveform generated from the electrocardiogram waveform becomes equal to or less than a negative constant C2. The constant C2 may be a different value depending on the type of differentiation circuit, etc. The constant C2 may be any value as long as it is below the value on the vertical axis of the baseline of the differential waveform.

[0064] In requirement 2, the timing at which the power supply 13 applies voltage to the electrode unit 5 may be any time after switching from the first mode to the second mode. For example, the timing at which the power supply 13 applies voltage to the electrode unit 5 may be after the start of the R wave but before the peak of the R wave, or after the peak of the R wave but before the end of the R wave. In requirement 2, it is preferable that the power supply 13 applies voltage to the electrode unit 5 before the end of the R wave that triggered the switching unit 30 to switch from the first mode to the second mode. In this way, by having the power supply 13 apply voltage to the electrode unit 5 before the end of the R wave that triggered the switching unit 30 to switch from the first mode to the second mode, treatment can be performed safely without transitioning to ventricular fibrillation.

[0065] In requirement 2, the power supply 13 may apply a voltage to the electrode unit 5 after the peak of the R wave that triggers the switching unit 30 to switch from the first mode to the second mode and before the end of the triggering R wave.

[0066] In requirement 2, the power supply 13 may apply a voltage to the electrode unit 5 after the start and before the end of an R wave that appears after the R wave that triggered the switching unit 30 to switch from the first mode to the second mode. Also, in requirement 2, the power supply 13 may apply a voltage to the electrode unit 5 after the start and before the end of an R wave that appears after the R wave that triggered the switching unit 30 to switch from the first mode to the second mode.

[0067] As shown in FIG. 2, the system 1 may have 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 switching unit 30 and the electrocardiograph 50 are connected via the first connection unit 15. In detail, the first switches 31A to 31D and the electrocardiograph 50 are connected via the first connection unit 15.

[0068] 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.

[0069] As shown in FIG. 2 , the switching unit 30 may have a first switch arranged on the first connection unit 15 side and a second switch arranged on the power supply 13 side. In this case, it is preferable that the first switch and the second switch are independent of each other. The switching unit 30 may have one or more first switches and one or more second switches. FIG. 2 shows an example in which the switching unit 30 has multiple first switches 31A-31D and multiple second switches 32A-32D. By having the first switch and the second switch, the switching unit 30 can appropriately switch the first switch and the second switch ON and OFF to output a DC voltage from the power supply 13 to each electrode, thereby applying a voltage and measuring an intracardiac potential. The first switch and the second switch refer to switch elements mounted on an electronic circuit board and are distinguished from operating switches such as push button switches and lever switches that are operated by a user to switch ON and OFF. The first switch being arranged on the first connection portion 15 side means that the first switch is arranged closer to the first connection portion 15 than the second switch. Furthermore, the second switch being arranged closer to the power source 13 than the first switch means that the second switch is arranged closer to the power source 13 than the first switch.

[0070] 2, the first switch and the second switch are preferably each connected to the power source 13. The phrase "the first switch and the second switch are each connected to the power source 13" includes both a case where the first switch or the second switch is connected to the power source 13 by a conductor and a case where the first switch or the second switch is connected to the power source 13 via a conductor or a member other than a conductor.

[0071] 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.

[0072] As shown in FIG. 2, the first switches 31A-31D are preferably connected in parallel to one another. The second switches 32A-32D are preferably connected in parallel to one another. This allows the electrodes to be electrically isolated, allowing each electrode to measure an intracardiac potential independently. The electrodes of the electrode unit 5 are preferably connected to a power source 13 via a second switch, and the electrodes of the electrode unit 5 are preferably connected to an electrocardiograph 50 via a first switch. In FIG. 2, the first electrode group 6 includes a first most distal electrode 6A and a first most proximal electrode 6B, and the second electrode group 7 includes a second most distal electrode 7A and a second most proximal electrode 7B. 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. Specifically, the first most distal electrode 6A is connected to the power supply 13 via the second switch 32A, the first most proximal electrode 6B is connected to the power supply 13 via the second switch 32B, the second most distal electrode 7A is connected to the power supply 13 via the second switch 32C, and the second most proximal electrode 7B is connected to the power supply 13 via the second switch 32D. In addition, the first most distal electrode 6A is connected to the electrocardiograph 50 via the first switch 31A, the first most proximal electrode 6B is connected to the electrocardiograph 50 via the first switch 31B, the second most distal electrode 7A is connected to the electrocardiograph 50 via the first switch 31C, and the second most proximal electrode 7B is connected to the electrocardiograph 50 via the first switch 31D.

[0073] 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.

[0074] 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.

[0075] In the first mode (cardiac potential measurement mode), 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), 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.

[0076] As shown in FIG. 2 , the system 1 may include an enable signal generating unit 21 connected to the power source 13 and configured to generate an enable signal to enable application of a voltage for defibrillation. The enable signal may be a signal related to application of a voltage for defibrillation, and may include, for example, 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 generating unit 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 or the like. The enable signal generating unit 21 may be directly or indirectly connected to the power source 13. The enable signal generating unit 21 may be provided in the control unit 20, which will be described later. Regarding requirement 1, it is preferable that the switching unit 30 switches from the first mode to the second mode after the enable signal generating unit 21 generates an enable signal, after detecting an R wave of an electrocardiogram signal, and before the end of the detected R wave.

[0077] The system 1 preferably has one or more operation units 40 for performing various operations such as turning the electrical device on and off, setting the amount of energy to be applied, 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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 and a push button switch. When the application execution switch 44 is pressed, 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.

[0082] 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.

[0083] 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.

[0084] As shown in FIG. 2 , the system 1 preferably includes a control unit 20 connected to the switching unit 30, and more preferably, to the first switches 31A-31D and second switches 32A-32D of the switching unit 30. This allows the control unit 20 to control each switch of the switching unit 30, thereby outputting a DC voltage from the power supply 13 to each electrode and performing defibrillation by applying a voltage. 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. Although not shown, the control unit 20 may include a first control unit that controls the ON / OFF switching of the first switches 31A-31D and a second control unit that controls the ON / OFF switching of the second switches 32A-32D.

[0085] 2, the system 1 preferably includes a delay unit 23 that delays the start timing of Requirement 2 so that Requirement 2 starts after a first predetermined time has elapsed following the end of Requirement 1. By providing the delay unit 23 in this manner, the timing of the mode switching by the switching unit 30 and the voltage application can be reliably shifted, so that defibrillation can 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 50 side.

[0086] The delay unit 23 is preferably connected to the switching unit 30. By providing the delay unit 23 in this manner, the operation timing of the switches in the switching unit 30 can be appropriately controlled, thereby reliably staggering the timing of the mode switching of the switching unit 30 and the voltage application. A known delay circuit such as an RC circuit can be used as the delay unit 23. When the switching unit 30 has one or more first switches, the delay unit 23 is preferably connected to one or more first switches. When the switching unit 30 has one or more second switches, the delay unit 23 is preferably connected to one or more second switches.

[0087] To ensure that requirement 2 starts after the first predetermined time has elapsed after requirement 1 has ended, the first predetermined time is preferably 5 ms or more, more preferably 8 ms or more, and even more preferably 10 ms or more. The first predetermined time is preferably 30 ms or less, more preferably 25 ms or less, and even more preferably 20 ms or less.

[0088] 2, in the system 1, a power output control unit 24 is preferably disposed in the connection path between the power supply 13 and the switching unit 30. The power output control unit 24 is more preferably disposed in the connection path between the power supply 13 and the second switches 32A to 32D. The power output control unit 24 can output the voltage input from the power supply 13 as pulsed power. By switching the polarity with the power output control unit 24, the polarity of the outputs from the first electrode group 6 and the second electrode group 7 can be reversed.

[0089] The power output control unit 24 may have one or more switches. In FIG. 2, the power output control unit 24 is shown to have third switches 33A-33B. When the power output control unit 24 has one or more switches, it is preferable that the system 1 be controlled so as to satisfy the following requirement 3 after requirement 1 and before requirement 2. (Requirement 3) After requirement 1, the switch (third switch) of the power output control unit 24 is turned from OFF to ON.

[0090] 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, thereby providing the power supply 13 with a fail-safe function that can prevent voltage from being unintentionally applied to the patient when, for example, the second switch fails.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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. 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. By measuring the impedance, it is possible to set an applied waveform suited to the patient. The impedance measuring unit 25 preferably completes the measurement of the impedance before applying a voltage, and more preferably before detecting the R wave of the electrocardiogram signal in Requirement 1.

[0096] After the application execution switch 44 is turned on, the impedance measurement unit 25 starts measuring the impedance, and then requirement 1 may be performed. After the application execution switch 44 is turned on, requirement 1 may be performed, and then the impedance measurement unit 25 starts measuring the impedance.

[0097] 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. 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.

[0098] 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.

[0099] 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.

[0100] 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 delay unit 23, the power output control unit 24, the impedance measuring unit 25, and the detection unit 27, may be realized by hardware or software. Examples of hardware include logic circuits formed in integrated circuits such as LSIs (Large Scale Integrations) and ASICs (Application Specific Integrated Circuits).

[0101] 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 enable signal generating unit 21, the input unit 22, the delay unit 23, the power output control unit 24, the impedance measuring unit 25, 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.

[0102] A control method for the intracardiac defibrillation catheter system 1 according to one embodiment of the present invention will be described with reference to FIG.

[0103] 1 and 2, the catheter system 1 to be controlled comprises a catheter 2 having a longitudinal axis direction, an electrode unit 5 disposed at the distal portion of the catheter 2, a power source 13 that applies a voltage to the electrode unit 5, an input unit 22 to which an electrocardiogram signal is input, and a switching unit 30 that is connected to the power source 13 and switches between a first mode in which the power source 13 and the electrode unit 5 are electrically disconnected and a second mode in which the power source 13 and the electrode unit 5 are electrically connected, the electrode unit 5 being connected to the power source 13 via the switching unit 30. For details of these configurations, please refer to the above description.

[0104] 4, the control method includes a step (step S1) of detecting an R wave of an electrocardiogram signal. The electrocardiogram signal for detecting the R wave may be an electrocardiogram signal measured by the electrode unit 5 of the catheter 2, i.e., an electrocardiogram signal obtained based on an intracardiac potential measured by the electrode unit 5 inserted into the heart, or an electrocardiogram signal obtained based on a body surface potential measured from electrodes attached to the body surface.

[0105] As shown in FIG. 4, the control method includes a step (step S2) in which the switching unit 30 switches from the first mode to the second mode before the end of the detected R wave.

[0106] Step S2 may be performed after detecting the peak of the R wave of the electrocardiogram signal. That is, the mode switching in step S2 may be started after the completion of step S1. When the detector 27 detects the peak 61R of the R wave, the power supply 13 can quickly apply a voltage to the electrode unit 5. This shortens the time from switching to the second mode in which defibrillation can be performed until voltage is applied to the electrode unit 5 to perform defibrillation, enabling safer treatment.

[0107] Step S2 may be performed after detecting the P-wave peak 61P of the electrocardiogram signal and after detecting the R-wave peak 61R. Step S2 may be performed after detecting the Q-wave peak 61P of the electrocardiogram signal and after detecting the R-wave peak 61R. Step S2 may be performed after detecting the P-wave peak, the Q-wave peak, and then the R-wave peak of the electrocardiogram signal. In this way, by combining the P-wave peak and / or the Q-wave peak with the R-wave peak, the possibility of false detection can be reduced, allowing for safer treatment.

[0108] Step S2 may be performed after detecting the rising edge of the R wave of the electrocardiogram signal. Alternatively, step S2 may be performed during the period from the rising edge of the R wave of the electrocardiogram signal to the peak of the R wave. Furthermore, step S2 may be performed after detecting the peak of the R wave of the electrocardiogram signal. For example, step S2 may be performed after the peak of the R wave of the electrocardiogram signal has passed and before the end of the R wave.

[0109] For details of the R wave detection method in step S2, the explanation of requirement 1 can be referred to.

[0110] As shown in FIG. 4, the control method includes a step in which the power supply 13 applies a voltage to the electrode unit 5 (step S3).

[0111] Step S3 may be performed at any time after step S2. For example, step S3 may be performed after the start of the R wave and before the peak of the R wave, or after the peak of the R wave and before the end of the R wave.

[0112] Step S3 may be performed before the end of the R wave that triggered the switching unit 30 to switch from the first mode to the second mode. In this way, by the power supply 13 applying a voltage to the electrode unit 5 before the end of the R wave that triggered the switching unit 30, treatment can be performed safely without transitioning to ventricular fibrillation.

[0113] Step S3 may be performed after the peak of the R wave that triggers the switching unit 30 to switch from the first mode to the second mode, but before the end of the R wave that triggered the switching unit 30 to switch from the first mode to the second mode.

[0114] Step S3 may be performed after the start and before the end of an R wave that appears after the R wave that triggered the switching unit 30 to switch from the first mode to the second mode. Alternatively, step S3 may be performed after the start and before the end of an R wave that appears after the R wave that triggered the switching unit 30 to switch from the first mode to the second mode.

[0115] The system 1 may include a delay unit 23 that delays the start timing of step S3 so that step S3 starts after a first predetermined time has elapsed after step S2 has ended. The above descriptions can be referred to for the description of the delay unit 23 and the first predetermined time.

[0116] For details of the timing of applying the voltage in step S3, the explanation of requirement 2 can be referred to.

[0117] According to the above control method, after detecting the R wave of the electrocardiogram signal, the mode is switched and voltage is applied to the electrode portion 5 before the end of the detected R wave, thereby shortening the time from mode switching to voltage application and enabling safer treatment.

[0118] A control method for system 1 according to another embodiment of the present invention will be described with reference to Fig. 5. As shown in Fig. 2, system 1 preferably has at least one of a main power switch 41, an application 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.

[0119] First, a step (step S11) is preferably performed in which the main power supply of the defibrillation electrical device 10 included in the system 1 is turned on. In step S11, the main power supply of the defibrillation electrical 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 switching unit is preferably in the first mode. For example, the first switches 31A to 31D of the switching unit 30 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.

[0120] 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.

[0121] 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.

[0122] It is preferable that a step (step S14) of inputting the charging switch 43 is performed. In step S14, after an input signal is generated from the charging switch 43, the switching unit 30 is preferably in the first mode. In step S14, the second switches 32A to 32D may be turned from OFF to ON, or may remain OFF. After an input signal is generated from the charging switch 43, it is preferable that the control unit 20 perform control to perform steps S15 and / or S16 described below. In step S14, it is preferable that the first switches 31A to 31D remain ON even after the charging switch 43 is input.

[0123] A step (step S15) of measuring impedance is preferably performed by the impedance measurement unit 25. In step S15, it is preferable to measure the impedance between the multiple electrodes of the electrode unit 5, and more preferably to measure the impedance between the electrodes of the first electrode group 6 and the electrodes of the second electrode group 7. In the switching unit 30, it is preferable that the second switches 32A to 32D remain ON from the start of impedance measurement to its completion. In the switching unit 30, it is preferable that the second switches 32A to 32D change from ON to OFF after the start of impedance measurement. 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.

[0124] 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 switching unit 30 is preferably in the first mode, and for example, the first switches 31A to 31D are preferably ON and the second switches 32A to 32D are preferably OFF.

[0125] 5, 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.

[0126] It is preferable to carry out a step (step S17) in which an enabling signal is generated from the enabling signal generating unit 21. In step S17, it is preferable that the control unit 20 performs control so that an enabling signal is generated from the enabling signal generating unit 21 after an 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 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.

[0127] A step of detecting an R wave of an electrocardiogram signal (step S18) is performed. For details of step S18, please refer to the description of step S1.

[0128] Before the end of the detected R wave, the switching unit 30 switches from the first mode to the second mode (step S19). For details of step S19, see the description of step S2.

[0129] A step (step S20) is performed in which the power supply 13 applies a voltage to the electrode portion 5. For details of step S20, refer to the description of step S3.

[0130] This application claims the benefit of priority based on Japanese Patent Application No. 2024-50716, filed on March 27, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-50716, filed on March 27, 2024, are incorporated herein by reference.

[0131] 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: Delay section 24: Power supply output control section 25: Impedance measuring 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 60: Electrocardiogram

Claims

1. An intracardiac defibrillation catheter system comprising: a catheter having a longitudinal axis direction; an electrode unit disposed in a distal portion of the catheter; a power source for applying a voltage to the electrode unit; an input unit to which an electrocardiogram signal is input; and a switching unit connected to the power source and for switching between a first mode in which the power source and the electrode unit are electrically disconnected and a second mode in which the power source and the electrode unit are electrically connected, wherein the electrode unit is connected to the power source via the switching unit, and is controlled to satisfy the following requirements 1 and 2. (Requirement 1) After detecting an R wave of the electrocardiogram signal, the switching unit switches from the first mode to the second mode before the end of the detected R wave. (Requirement 2) After requirement 1 above, the power source applies a voltage to the electrode unit.

2. An intracardiac defibrillation catheter system according to claim 1, wherein the switching unit switches from the first mode to the second mode after detecting a peak of an R wave of the electrocardiogram signal.

3. An intracardiac defibrillation catheter system according to claim 1, wherein the switching unit switches from the first mode to the second mode after detecting the rising edge of an R wave of the electrocardiogram signal.

4. An intracardiac defibrillation catheter system according to claim 1 or 2, wherein, in requirement 2, the power source applies voltage to the electrode unit before the end of an R wave that triggers the switching unit to switch from the first mode to the second mode.

5. An intracardiac defibrillation catheter system as described in claim 1 or 2, wherein the input unit is connected to an electrocardiograph, and the intracardiac defibrillation catheter system has a detection unit connected to the input unit that detects R waves using the electrocardiogram signal from the electrocardiograph input to the input unit.

6. An intracardiac defibrillation catheter system as described in claim 5, which has a first connection part connected to the electrocardiograph, and the switching part has a first switch arranged on the side of the first connection part and a second switch arranged on the side of the power supply, and the first switch and the second switch are independent of each other.

7. An intracardiac defibrillation catheter system as described in claim 1 or 2, which has a delay unit that delays the start timing of requirement 2 so that requirement 2 starts after a first predetermined time has elapsed after requirement 1 has ended.

8. 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 input portion to which an electrocardiogram signal is input; and a switching portion connected to the power source for switching between a first mode in which the power source and the electrode portion are electrically disconnected and a second mode in which the power source and the electrode portion are electrically connected, wherein the electrode portion is connected to the power source via the switching portion, the control method for an intracardiac defibrillation catheter system comprising: a step of detecting an R wave of the electrocardiogram signal; a step of the switching portion switching from the first mode to the second mode before the end of the detected R wave; and a step of the power source applying a voltage to the electrode portion.

9. The method for controlling an intracardiac defibrillation catheter system according to claim 8, wherein the step of switching from the first mode to the second mode by the switching unit is performed after detecting the peak of the R wave of the electrocardiogram signal.

10. A method for controlling an intracardiac defibrillation catheter system according to claim 8, wherein the step of switching the switching unit from the first mode to the second mode is performed after detecting the rising edge of an R wave in the electrocardiogram signal.

11. A method for controlling an intracardiac defibrillation catheter system according to claim 8 or 9, wherein the step of the power source applying a voltage to the electrode unit is performed before the end of the R wave that triggered the switching unit to switch from the first mode to the second mode.

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