JP3110937B2 - Bioimplantable cardiac pacemaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bioimplantable cardiac pacemaker incorporating a transcutaneously rechargeable battery.

[0002]

2. Description of the Related Art A bioimplantable cardiac pacemaker needs to incorporate a battery as a power source, but cannot be charged with a general primary battery. When the battery reaches the end of its life, it is necessary to re-implant a device for battery replacement. Is required, and the mental and physical burden on the patient is great.

[0003] Therefore, there is a device in which a rechargeable secondary battery is built in a cardiac pacemaker, an AC electromagnetic field is generated outside the body, and the power is transmitted percutaneously into the body to charge the secondary battery. .

In such a cardiac pacemaker, an electronic circuit control module for performing pacing pulse control to be applied to the myocardium and a secondary battery are built in a metal case to receive an AC electromagnetic field sent from outside the body. A coil wound on a flat or rod-shaped core was placed outside the case.

[0005]

As described above, the electronic circuit control module is built in the metal case, and the AC electromagnetic field receiving coil is arranged outside the case, so that the electronic circuit control module can be connected to the electronic circuit control module during charging. , And the power receiving efficiency of the power receiving coil, that is, the coupling rate with the power transmitting coil and the power transmission efficiency can be increased.

However, it is inevitable that the power receiving coil generates heat by receiving the AC electromagnetic field. Since the temperature rise reaches 5 to 6 ° C. according to the experiment, the living tissue in contact therewith may cause a low-temperature burn.

Accordingly, the present invention provides a safe living body implant that not only has a small noise penetration into the electronic circuit control module and a good power receiving efficiency of the power receiving coil, but also has a small temperature rise during charging and does not have a risk of generating a low-temperature burn. It is an object of the present invention to provide a cardiac pacemaker.

[0008]

In order to achieve the above object, a living body implantable cardiac pacemaker according to the present invention comprises an electronic circuit control module for controlling pacing pulses applied to a myocardium, and a power supply for the electronic circuit control module. A rechargeable battery, a power receiving coil for externally receiving an AC electromagnetic field as energy for charging the battery, and a rectifying AC voltage output from the power receiving coil to the battery. In a biologically implantable cardiac pacemaker integrally provided with a rectifying circuit module to be sent,
The electronic circuit control module and the battery are housed in a metal case, the power receiving coil and the rectifying circuit module are arranged outside the metal case, and a high magnetic material is adhered to both the power receiving coil and the case. The power receiving coil and the case are covered with a biocompatible material so that at least the power receiving coil, the high magnetic material, and the rectifier circuit module are not exposed to the outside. .

The power receiving coil and the high magnetic material are both formed in a disk shape, and one surface of the high magnetic material is brought into close contact with the power receiving coil surface, and the other surface is brought into close contact with the metal case surface. Preferably, an amorphous alloy is used as the high magnetic material.

[0010]

The power receiving coil receives an externally transmitted AC electromagnetic field outside the metal case, and the generated AC voltage is rectified to DC by the rectifier circuit module outside the metal case. It is the rectified voltage that is sent into the metal case, which charges the battery in the metal case.

[0011] The heat generated in the power receiving coil by receiving the AC electromagnetic field is transmitted from the high-magnetic material disposed closely to the metal case to the metal case disposed further in close contact with the high-magnetism material, and dispersed. Escape to the organization side. Therefore, the temperature rise of the heat generating portion is very small.

[0012]

An embodiment will be described with reference to the drawings. FIG.
1 shows an implantable cardiac pacemaker according to an embodiment of the present invention, and an electronic circuit control module 50 for performing pacing pulse control applied to a myocardium based on a biological signal.
And a rechargeable secondary battery 53 serving as a power source thereof are housed in a metal case 51 in a sealed state. Reference numeral 56 denotes a power supply line for supplying power from the secondary battery 53 to the electronic circuit control module 50.

As a material of the case 51, a metal or a metal alloy which does not corrode in a living body should be used. For example, titanium or the like is suitable. One wall surface of the case 51 is formed so that a central portion thereof is dished in a dish shape, and a high magnetic material plate 55 made of a high magnetic material having good heat conductivity in the form of a thin donut disk is disposed in close contact therewith. ing.

If a sheet made of, for example, an amorphous alloy is used as the high magnetic material plate 55, strong magnetism can be obtained even if it is thin. Here, for example, two amorphous alloy sheets each having a thickness of 20 μm are used in an overlapping manner. However, in the present invention, one or a plurality of permalloy metal,
High magnetic materials having good thermal conductivity such as nickel, cobalt, or alloys thereof can be used.

As shown in FIG. 2, on the front side of the high magnetic material plate 55, a power receiving coil 52 formed in the shape of a donut disk having the same shape as that of the high magnetic material plate 55 is shown in FIG. As described above, it is disposed so as to be in close contact with the high magnetic material plate 55 face to face. The power receiving coil 52 has, for example, a wire diameter of 0.1 mm.
Is spirally wound, for example, 100 to 200 times, in a single layer or a plurality of layers to form a disk as a whole.

Therefore, the power receiving coil 52 and the case 5
1, a high-magnetic material plate 55 is sandwiched between them, and they are all arranged in close contact with each other, and they are joined by an adhesive having good heat conductivity, for example, heat transfer cement. The heat generated in the coil 52 for the high magnetic material plate 5
5 to the case 51.

A rectifier circuit module 60 for rectifying an AC voltage into a DC is disposed at a central portion between the doughnut-shaped high magnetic material plate 55 and the power receiving coil 52. Connected, output end is case 5
It is connected to the secondary battery 53 in the case 51 via a glass sealing lead 66 penetrating through the first wall.

Therefore, when the power receiving coil 52 receives an AC electromagnetic field sent from the outside (externally), the power receiving coil 52 is placed in a state where the power receiving efficiency is greatly increased by the high magnetic material plate 55 juxtaposed thereto. , An output thereof is rectified by the rectifier circuit module 60, and a DC component is sent into the case 51 to charge the secondary battery 53.

The periphery of the case 51, the power receiving coil 52, the high magnetic material plate 55, and the rectifying circuit module 60 are made of, for example, epoxy resin, silicon resin, polyurethane resin, polyethylene resin, polyester resin, polyacetal resin, or a composite material thereof. It is covered with a polymer resin material 59 having high biocompatibility so as not to be exposed on the surface. Therefore, the surrounding living tissue in which the device is implanted does not cause inflammation or the like.

It is not always necessary to completely cover the periphery of the case 51, but at least the power receiving coil 52, the high magnetic material plate 55, and the rectifying circuit module 60 are completely covered so as not to come into contact with the living body at all. It is desirable to do.

As shown in FIG. 3, a part of the covering material 59 is formed so as to be partially protruded, and a connector 70 for connecting atrial and ventricular leads is formed thereon. .

In FIG. 1, reference numeral 71 denotes a set screw for fixing a conductive piece in the connector 70;
This is a glass sealing lead connecting between the electronic circuit control module 50 and the electronic circuit control module 50.

FIG. 4 shows a configuration of a charging circuit for charging the secondary battery 53 from outside the body. Reference numeral 1 denotes a primary battery as a power source for a charger arranged outside the body. 10
Is a transformer circuit for transforming (stepping up / down) the voltage of the primary battery 1 outside the body in order to make the strength of the AC electromagnetic field for transdermal charging correspond to the voltage of the secondary battery 53 and the like. , An inductance 11, a switching transistor 12, a diode 13, a smoothing capacitor 14, and the like.

In order to obtain a desired DC voltage by performing a step-up or step-down operation in the transformer circuit 10, the pulse width of a control pulse applied to a gate for turning on the switching transistor 12 may be adjusted.

Reference numeral 20 denotes an inverter circuit for generating an AC electromagnetic field for transcutaneous charging, which is basically configured by combining four switching transistors 21 to 24 in series and parallel in a bridge shape.

In the inverter circuit 20, the DC voltage supplied from the transformer circuit 10 is applied to two switching transistors 21 to 24 (21 and 24 and 22 and 2
3) An AC voltage is generated between A and B in the figure by controlling the conduction at different times in combination.

To change the amplitude of the AC voltage or stop the generation, two sets of switching transistors 21 and
This can be implemented by changing the time width of the control pulse applied to the gates of the gates 4 and 22 and 23 or by stopping the applied control pulse. 25 is a smoothing capacitor.

Reference numeral 31 denotes a power transmission coil for transmitting power to a device implanted in a living body based on the AC voltage generated by the inverter circuit 20, and the coil specifies the radiation directivity of the electromagnetic field. It is braided into a ferrite core or the like to increase its strength.

Reference numeral 100 denotes a living tissue such as muscle or fat interposed between the skin surface of the living body and the device implanted in the living body (hereinafter, referred to as "living body skin 100"). Reference numeral 51 denotes a metal case of a cardiac pacemaker to be implanted in a living body.

Reference numeral 52 denotes a disc-shaped power receiving coil disposed outside the metal case 51. The power receiving coil 31 transmits an AC electromagnetic field for charging to the outside of the body via the skin 100 of the living body.
Receives power from 55 is a high magnetic material plate juxtaposed with the power receiving coil 52.

Reference numeral 60 denotes a rectifier circuit module for receiving power.
Four diodes 61 to 6 combined in a bridge
4 and a smoothing capacitor 65. The AC voltage received by the power receiving coil 52 is full-wave rectified to remove a ripple.

Reference numeral 53 denotes a chargeable secondary battery that supplies electrical energy for operation and control to the implanted device, and is charged by a DC output of the power receiving rectifier circuit 60.
As a charging method, either constant voltage charging or constant current charging may be adopted. Reference numeral 56 denotes a power supply line to the electronic circuit control module 50.

Reference numeral 54 denotes when the secondary battery 53 is charged.
It is a current monitoring resistor having a known resistance value for monitoring a charging current. Reference numeral 57 denotes a telemetry transmission circuit that modulates and transmits a carrier signal in order to transmit monitor information of the charging current to a charger outside the body by telemetry, and 58 denotes a transmission antenna coil.

The transmission signal from the telemetry transmission circuit 57 is transmitted from the transmission antenna coil 58 to the outside of the body via the metal case 51 and the skin 100 of the living body, and is received by the telemetry signal reception antenna coil 32 outside the body. 33
Is a telemetry receiving circuit for demodulating the received telemetry signal.

Reference numeral 34 denotes an inverter control circuit for controlling the operation of the inverter circuit 20. For example, when receiving a telemetry signal indicating that charging is completed and charging should be stopped, the switching transistors 21 to 21 of the inverter circuit 20 are received. In order to stop the operation of 24, a control pulse applied to the gate is output to make it non-conductive.

Reference numeral 35 denotes a charge control circuit. For example, when a telemetry signal indicating that the charging current should be further increased is received, the switching transistor 1
The pulse applied to the gate is controlled so as to increase the conduction period of No. 2. Reference numeral 36 denotes a display / alarm / operation circuit for monitoring information on the state of charge of the secondary battery 53 with the extracorporeal chargers 10 and 20 and performing various necessary operations.

According to the implantable cardiac pacemaker of the embodiment configured as described above, the power receiving coil 5 in the body is provided.
2 is provided outside the metal case 51, and the high magnetic material plate 55 is provided side by side with the metal case 51. Therefore, the power receiving efficiency of the AC electromagnetic field transmitted from outside the body is good, and the power transmitting coil 3 is provided.
High values such as a coupling ratio (voltage ratio) to 1 and a power transmission efficiency of 0.4 to 0.45 can be obtained. Therefore, the power consumption on the power transmission side can be a very low value, for example, about 0.7 W.

The power receiving coil 52 is connected to the metal case 51.
However, since the electronic circuit control module 50 is housed in the metal case 51, there is little noise intrusion into the electronic circuit control module 50 due to the charging AC electromagnetic field. In particular, since only the rectified DC component enters the metal case 51, the inside of the case 51 has an environment in which noise is hardly generated.

Then, a disk-shaped high magnetic material plate 55 having good heat conductivity is placed on both sides of the power receiving coil 52 and the metal case 5.
Since it is sandwiched between the two so as to be in close contact with the first member, heat generated in the power receiving coil 52 is diffused to the metal case through the high magnetic material plate 55 and transmitted to the living body. As a result, the temperature rise of the heat generating portion is limited to, for example, 2 to 3 ° C., and there is no possibility that a low-temperature burn or the like occurs.

[0040]

According to the present invention, not only the noise intrusion into the electronic circuit control module is small and the power receiving efficiency of the power receiving coil is good, but also the heat generated in the power receiving coil passes through the high magnetic material plate to the metal case. Since the heat is diffused, the temperature rise of the heat generating portion is small, and there is no possibility of generating a low-temperature burn, and the safety is very high.

By forming both the power receiving coil and the high-magnetic material in a disk shape and bringing the two disk surfaces into close contact with each other, rapid heat conduction can be performed with a large heat conduction area. If an alloy is used, high magnetism and good thermal conductivity can be obtained.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a living body implantable cardiac pacemaker of an embodiment.

FIG. 2 is a partially exploded perspective view of a power receiving unit of the living body implantable cardiac pacemaker of the embodiment.

FIG. 3 is a perspective view of the biological implantable cardiac pacemaker of the embodiment.

FIG. 4 is a charging circuit diagram of the embodiment.

[Explanation of symbols]

 Reference Signs List 50 electronic circuit control module 51 metal case 52 power receiving coil 53 secondary battery 55 high magnetic material plate 59 polymer resin material 60 rectifier circuit module

──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuhiro Shirakawa, 1500, Inoguchi, Nakai-machi, Ashigara-gun, Kanagawa Prefecture Inside the Cardiopacing Research Research Laboratory (72) Shinji Ishida 1500, Inoguchi, Nakai-machi, Inaguchi, Ashigara-gun, Kanagawa Inside the Geopacing Research Laboratory (72) Inventor Katsuya Hirachi 1500 Inoguchi, Nakai-machi, Ashigarakami-gun, Kanagawa Prefecture Inside the Cardiopacing Research Laboratory Laboratory (72) Koji Kuwana 1500 Inoguchi, Nakai-cho, Ashigarakami-gun, Kanagawa Car Co., Ltd. In the Geopacing Research Laboratory (56) References JP-A-5-317433 (JP, A) JP-A-49-64283 (JP, A) JP-A-1-93930 (JP, U) JP-A 49-64 112090 (JP, U) Special public 51-11772 (JP, B1) (58 ) investigated the field (Int.Cl. ^7, DB name) A61N 1/378

Claims (3)

(57) [Claims] 1. An electronic circuit control module for performing pacing pulse control applied to a myocardium, a rechargeable battery serving as a power supply of the electronic circuit control module, and an AC electromagnetic field as energy for charging the battery. In a living body implantable cardiac pacemaker integrally provided with a power receiving coil for receiving power from the outside and a rectifying circuit module for rectifying an AC voltage output from the power receiving coil and sending the rectified power to the battery, the electronic circuit control A module and a battery are housed in a metal case, the power receiving coil and the rectifying circuit module are arranged outside the metal case, and a high-magnetic material is tightly attached to both the power receiving coil and the case. So that at least the power receiving coil, the high magnetic material, and the rectifier circuit module are not exposed to the outside. A bioimplantable cardiac pacemaker characterized by being coated with a biocompatible material. 2. The power receiving coil and the high magnetic material are both formed in a disk shape, and one surface of the high magnetic material is in close contact with the power receiving coil surface and the other surface is on the metal case surface. The living body implantable cardiac pacemaker according to claim 1, which is in close contact. 3. The living body implantable cardiac pacemaker according to claim 1, wherein an amorphous alloy is used as said high magnetic material.