ELECTRONIC DEMAND HEART PACEMAKER WITH DIFFERENT PACING AND STANDBY RATES

• US 3,656,487 A
• Filed: 01/07/1970
• Issued: 04/18/1972
• Est. Priority Date: 06/12/1969
• Status: Expired due to Term

• Current Assignee: David H. Gobeli
• Original Assignee: David H. Gobeli
• Inventors: Gobeli, David H.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/001,178
• Time in Patent Office: 832 Days
• Field of Search: 128/419P,419D,421,422
• US Class Current: 607/9
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371

Abstract

A demand type heart pacer which provides electronically generated stimulating pulses to the heart at a first frequency in the continued absence of natural heartbeats, but which inhibits output pulses once the natural heart rate exceeds the first frequency, and allows the heart to beat naturally at any rate above a second, lower frequency before again providing stimulating pulses, thereby creating a different standby frequency. The pacer also reverts to a third frequency in a nondemand type operation in the presence of an interfering electrical noise pattern.

Claims

1. In a demand type heart pacer including input and output means adapted to be connected to a heart, the input means connected to means for sensing natural heartbeats, the improvement comprising:

pulse generator means connected to the output means and including timing circuit means operable to control output pulses from said generator means at a selected frequency;

means connecting the means for sensing natural heartbeats to said pulse generator means for resetting said timing circuit means on the occurrence of a natural heartbeat; and

further timing circuit means connected to said timing circuit means for changing the frequency of output pulses from said generator means for one pulse cycle following a pulse cycle in which a natural heartbeat occurs.

2. In a demand heart pacemaker including power supply means, sensing means for detecting a natural heartbeat, pulse generator means for supplying pulses to stimulate a heartbeat and means for connecting the sensing means and generator means to a heart, the improvement comprising:

resistor means and first capacitor means serially connected across the power supply means;

said first capacitor means connected to the pulse generator means for controlling the frequency of pulses therefrom according to the charging time of said first capacitor means; and

circuit means including second capacitor means connected to said first capacitor means for selectively changing the charge time of said first capacitor means for one pulse cycle following a pulse cycle in which the natural heartbeat occurs.

3. In a demand type heart pacer including input and output means adapted to be connected to a heart, the input means connected to means for sensing natural heartbeats, the improvement comprising:

pulse generator means connected to the output means and including timing circuit means operable to control output pulses from said generator means at a selected frequency; and

further means connecting the means for sensing natural heartbeats to said pulse generator means for resetting said timing circuit means on the occurrence of a natural heartbeat and including further timing circuit means operably connected to said timing circuit means on the occurrence of a natural heartbeat for decreasing the frequency of output pulses from said generator means for one pulse cycle following a pulse cycle in which a natural heartbeat occurs.

4. The apparatus of claim 3 in which:

said timing circuit means includes resistor means and capacitor means connected in an RC timing circuit; and

said further timing circuit means includes further capacitor means and switch means for connecting said further capacitor means into said RC timing circuit.

5. The apparatus of claim 3 in which:

said timing circuit means includes serially connected resistance means and capacitance means; and

said further timing circuit means includes further capacitance means, means including diode means connecting said further capacitance means across said capacitance means, said diode means poled to prevent said further capacitance means from discharging into said capacitance means, and switch means connected across said further capacitance means and connected to said further means for discharging all said capacitance means on the occurrence of a natural heartbeat.

6. In a demand heart pacer including power supply means, sensing means for detecting a natural heartbeat, pulse generator means for supplying pulses to stimulate a heartbeat and means for connecting the sensing means and generator means to a heart, the improvement comprising:

resistor means and first capacitor means serially connected across the power supply means;

said first capacitor means connected to the pulse generator means for controlling the frequency of pulses therefrom according to the charging time of said first capacitor means; and

circuit means connected to the sensing means and to said first capacitor means and operable in response to the occurrence of a natural heartbeat for changing the charge time of said first capacitor means for one pulse cycle following a pulse cycle in which the natural heartbeat occurs.

7. The apparatus of claim 6 in which said circuit means comprises:

second capacitor means;

switch means connected between the sensing means and said first and second capacitor means for connecting said first and second capacitor means in parallel charging paths in response to the occurrence of a natural heartbeat for increasing the charging time of said first capacitor means.

8. The apparatus of claim 6 including noise responsive means for blocking repetitive noise signals from said circuit means comprising:

capacitor means having an input plate connected to the sensing means and an output plate connected to said circuit means;

a first discharge path for said capacitor means connected to said output plate and including serially connected diode means and resistor means, said diode means poled to pass current of a first polarity, said resistor means having a resistance value selected for generally fast discharge of said capacitor means; and

a second discharge path for said capacitor means connected to said output plate and including further resistor means having a resistance value selected for generally slow discharge of said capacitor means for charging said capacitor means with repeated noise pulses of a second polarity at a frequency above that of the normal heartbeat range to block further of said noise pulses of the second polarity.

9. In a demand pacer having input and output means adapted to be connected to a heart, pulse generator means connected to the output means and sensing means for detecting natural heartbeats connected to the input means, the improvement comprising:

resistor means and first capacitor means connected in an RC timing circuit and to the pulse generator means for controlling the frequency of the pulse generator means according to the charge time of said first capacitor means;

first switch means connected to said first capacitor means and to the pulse generator means, and actuated by an output pulse from the pulse generator means to discharge said first capacitor means;

second capacitor means;

means including diode means connecting said second capacitor to said first capacitor means, said diode means poled to permit said first and second capacitor means to charge in parallel and to prevent the discharge of said second capacitor means by said first switch means; and

second switch means connected to said second capacitor means and the sensing means, and actuated by a natural heartbeat to discharge said first and second capacitor means.

10. The apparatus of claim 9 including noise responsive means comprising:

third capacitor means connected between the sensing means and said second switch means;

second resistor means;

further diode means;

third resistor means;

means for connecting said second resistor means across said third capacitor means to provide a first discharge path, and for connecting said further diode means and said third resistor means across said third capacitor means to provide a second discharge path for one electrical polarity; and

said second and third resistor means having resistances selected to make the time constant of said first discharge path substantially greater than the time constant of said second discharge path.

11. In a demand type heart pacer including input and output means adapted to be connected to a heart, the input means connected to means for sensing natural heartbeats, the improvement comprising:

pulse generator means connected to the output means and including timing circuit means operable to control output pulses from said generator means at a selected frequency;

further means connecting the means for sensing natural heartbeats to said pulse generator means for resetting said timing circuit means on the occurrence of a natural heartbeat; and

further timing circuit means operably connected to saId timing circuit means on the occurrence of an output pulse from said pulse generator for increasing the frequency of output pulses from said generator means for one pulse cycle following the absence of a natural heartbeat.

12. The apparatus of claim 11 in which:

said timing circuit means includes resistor means and capacitor means connected in an RC timing circuit; and

said further timing circuit means includes further capacitor means connected to said RC timing circuit and switch means operable on the occurrence of an output pulse from said pulse generator for charging said further capacitor means.

13. The apparatus of claim 11 in which:

said timing circuit means includes serially connected resistance means and capacitance means; and

said further timing circuit means includes further capacitance means, means connecting said further capacitance means across said capacitance means, switch means adapted to connect said further capacitance means across a source of energy, and means connecting said switch means to said pulse generator for receiving pulses therefrom.

14. In a demand heart pacer including power supply means, pulse generator means for supplying stimulating pulses to a heart and means for connecting the generator means to a heart, the improvement comprising:

resistor means and first capacitor means serially connected across the power supply means;

said first capacitor means connected to the pulse generator means for controlling the frequency of pulses therefrom according to the charging time of said first capacitor means; and

circuit means connected to the pulse generator and to said first capacitor means and operable in response to the occurrence of a generated stimulating pulse for changing the charge time of said first capacitor means.

15. The apparatus of claim 14 in which said circuit means comprises:

second capacitor means;

switch means connecting said second capacitor means across the power supply;

said switch means connected to and controllable by the pulse generator for charging said second capacitor means on the occurrence of a generated stimulating pulse; and

means connecting said first and second capacitor means in parallel for decreasing the charging time of said first capacitor means.

16. The apparatus of claim 14 including noise responsive means for blocking repetitive noise signals from said circuit means comprising:

capacitor means having an input plate connected to the sensing means and an output plate connected to said circuit means;

a first discharge path for said capacitor means connected to said output plate and including serially connected diode means and resistor means, said diode means poled to pass current of a first polarity, said resistor means having a resistance value selected for generally fast discharge of said capacitor means; and

a second discharge path for said capacitor means connected to said output plate and including further resistor means having a resistance value selected for generally slow discharge of said capacitor means for charging said capacitor means with repeated noise pulses of a second polarity at a frequency above that of the normal heartbeat range to block further of said noise pulses of the second polarity.

17. In a demand pacer having input and output means adapted to be connected to a heart, pulse generator means connected to the output means and sensing means for detecting natural heartbeats connected to the input means, the improvement comprising:

resistor means and first capacitor means connected in an RC timing circuit and to the pulse generator means for controlling the frequency of the pulse generator means according to the charge time of said first capacitor means;

first switch means connected to said first capacitor means and to the sensing means, and actuated by a pulse from the sensing means to discharge said first capacitor means;

second capacitor means;

means connecting said second capacitor to said first capacitor means for discharging said second capacitor into said first capaciTor; and

second switch means connected to said second capacitor means and the pulse generator means and actuated by a generated pulse to charge said second capacitor means.

18. The apparatus of claim 17 including noise responsive means comprising:

third capacitor means connected between the sensing means and said first switch means;

second resistor means;

diode means;

third resistor means;

means for connecting said second resistor means across said third capacitor means to provide a first discharge path, and for connecting said diode means and said third resistor means across said third capacitor means to provide a second discharge path for one electrical polarity; and

said second and third resistor means having resistances selected to make the time constant of said first discharge path substantially greater than the time constant of said second discharge path.

19. In a heart pacer including input and output means adapted to be connected to a heart, the input means connected to sensing means for detecting a natural heartbeat and the output means connected to pulse generator means for supplying pulses to stimulate a heart, noise responsive means for preventing repetitive noise signals sensed by the sensing means from disabling the pulse generator means comprising:

capacitor means having an input plate connected to the sensing means and an output plate connected to the pulse generator means;

a first discharge path for said capacitor means connected to said output plate and including serially connected diode means and resistor means, said diode means poled to pass current of a first polarity, said resistor means having a resistance value selected for generally fast discharge of said capacitor means; and

a second discharge path for said capacitor means connected to said output plate and including further resistor means having a resistance value selected for generally slow discharge of said capacitor means for charging said capacitor means with repeated noise pulses of a second polarity at a frequency above that of the normal heartbeat range to block further of said noise pulses of the second polarity.

20. In a demand type heart pacer having pulse generator means including timing means operable to control output pulses from the generator means at a selected frequency, having sensing means for sensing natural heartbeats including means refractory to applied signals for a predetermined refractory period following each pacer pulse, having reset means, operatively connected to the pulse generator means, for resetting the timing means upon occurrence of each output pulse and having means connected to the pulse generator means and the sensing means and adapted to be connected to a heart;

the improvement comprising;

further means, operatively connecting the sensing means to the pulse generator means, for resetting the timing means for a predetermined limited time upon termination of the refractory period in response to repetitive signals, sensed by the sensing means, which exceed a predetermined rate greater than a natural heart rate and including means for preventing the timing means from continuous resetting in response to such repetitive signals, thereby decreasing the frequency of output pulses from the pulse generator means and causing the pacer to operate asynchronously.