Defibrillation pacing circuitry

• US 6,952,608 B2
• Filed: 11/05/2001
• Issued: 10/04/2005
• Est. Priority Date: 11/05/2001
• Status: Expired due to Term

• Current Assignee: Cameron Incorporated (Schlumberger NV)
• Original Assignee: Cameron Incorporated (Schlumberger NV)
• Inventors: Ostroff, Alan H.
• Primary Examiner(s): Evanisko, George R.
• Application Number:
  US10/011,955
• Publication Number:
  US 20030088282A1
• Time in Patent Office: 1,429 Days
• Field of Search: 607 4- 9, 607/14
• US Class Current: 607/5
• CPC Class Codes: A61N 1/362 Heart stimulators heart defibrillators A61N1/39
• CPC Class Codes: A61N 1/3912 Output circuitry therefor, e.g. switches
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

Electrical circuit componentry is switchable into a defibrillator circuit to deliver a constant pacing current to a patient. The circuitry may include a constant current source inserted in a leg of the defibrillator circuit or a resistor of selected value inserted between a high voltage source and the high side of a defibrillator circuit.

Claims

1. The apparatus comprising:

an H-bridge defibrillator circuit; and

means switchable into and out of the circuit for causing a constant current to flow through a patient connected to the circuit, wherein

the H-bridge defibrillator circuit includes a high side and a low side, each side having first and second selectable legs, wherein at least one of the selectable legs of the low side includes a resistance;

the means for causing comprises means for imposing a constant voltage across the resistance located in the low side of the circuit;

the means for imposing comprises a constant voltage source;

the means for imposing includes a switching device having a control terminal;

the voltage source applies a constant voltage to a control terminal of the switching device in the means for imposing;

the switching device includes a first output leg and a second output leg;

the resistance is located in an output leg of the switching device; and

the constant voltage source comprises a digital to analog converter (DAC).

2. The apparatus of claim 1 wherein the constant voltage source further comprises a feedback circuit, the feedback circuit configured to stabilize a voltage across the resistance in the low side of the H-bridge circuit at a level corresponding to the output of the DAC.

3. The apparatus comprising:

an H-bridge defibrillator circuit; and

means switchable into and out of the circuit for causing a constant current to flow through a patient connected to the circuit, wherein

the H-bridge defibrillator circuit includes a high side and a low side, each side having first and second selectable legs, wherein at least one of the selectable legs of the low side includes a resistance;

the means for causing comprises means for imposing a constant voltage across the resistance located in the low side of the circuit;

the means for imposing comprises a constant voltage source;

the means for imposing includes a switching device having a control terminal;

the voltage source applies a constant voltage to a control terminal of the switching device in the means for imposing; and

the constant voltage source comprises a digital to analog converter (DAC).

4. The apparatus a claim 3 wherein the constant voltage source further comprises a feedback circuit, the feedback circuit configured to stabilize a voltage across the resistance in the low side of the H-bridge circuit at a level corresponding to the output of the DAC.

5. The apparatus comprising:

circuit means for delivering a defibrillating current pulse to a patient; and

means switchable into and out of connection with the circuit means for causing a constant current to flow through the patient during a period when a current pulse is not being delivered;

wherein;

the circuit means includes high side circuitry for delivering current to the patient and low side circuitry for receiving current from the patient, the low side circuitry including a resistance;

the means for causing comprises means for imposing a constant voltage across the resistance located in the low side circuitry of the circuit means;

the means for imposing comprises a constant voltage source; and

the constant voltage source comprises a digital to analog converter (DAC).

6. The apparatus of claim 5 wherein the constant voltage source further comprises a feedback circuit, the feedback circuit configured to stabilize a voltage across the resistance in the low side circuitry at a level corresponding to the output of the DAC.

7. The apparatus comprising:

circuit means for delivering a defibrillating current pulse to a patient; and

means switchable into and out of connection with the circuit means for causing a constant current to flow through the patient during a period when a current pulse is not being delivered;

wherein;

the circuit means includes high side circuitry for delivering current to the patient and low side circuitry for receiving current from the patient, the low side circuitry including a resistance;

the means for causing comprises means for imposing a constant voltage across the resistance located in the low side circuitry of the circuit means;

the means for imposing comprises a constant voltage source;

the means for causing a constant current includes a switching device having a control terminal;

the voltage source applies a constant voltage to a control terminal of the switching device in the means for causing a constant current; and

the constant voltage source comprises a digital to analog converter (DAC).

8. The apparatus of claim 7 wherein the constant voltage source further comprises a feedback circuit, the feedback circuit configured to stabilize a voltage across the resistance in the low side circuitry at a level corresponding to the output of the DAC.