Defibrillation pacing circuitry

• US 7,522,957 B2
• Filed: 06/07/2005
• Issued: 04/21/2009
• Est. Priority Date: 11/05/2001
• Status: Expired due to Term

• Current Assignee: Cameron Health Inc (Boston Scientific Corporation)
• Original Assignee: Cameron Health Inc (Boston Scientific Corporation)
• Inventors: Ostroff, Alan H.
• Primary Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US11/146,607
• Publication Number:
  US 20050288714A1
• Time in Patent Office: 1,414 Days
• Field of Search: 607/4, 607/5, 607/7, 607/8
• US Class Current: 607/4
• 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. A method of providing stimulus to a patient using an H-bridge circuit via implanted electrodes from an implantable medical device having a battery power source, the method comprising:

providing, on a low side of the H-bridge, a resistor in series with a portion of the H-bridge circuit and in parallel with an opt-out switch;

selecting a first mode or a second mode; and

;

when in the first mode, capturing a feedback signal from between the resistor and the H-bridge and using the feedback signal to generate a control signal controlling current flow through the resistor;

or

when in the second mode, closing the opt-out switch to short the resistor, and wherein the implantable medical device is capable of operating in both modes.

2. The method of claim 1, wherein the resistor and parallel opt-out switch are placed in series with a first low side switch of the H-bridge circuit.

3. The method of claim 2, wherein the first low side switch has an input, an output, and a control terminal, wherein the control signal is applied to the control terminal of the first low side switch.

4. The method of claim 3, wherein the H-bridge further includes a second low side switch and first and second high side switches, each of the switches including an input, an output, and a control terminal, the output of the first high side switch electrically coupled to the input of the first low side switch at a node coupled to a first electrode for the device, the output of the second high side switch electrically coupled to the input of the second low side switch at a node coupled to a second electrode for the device.

5. The method of claim 4, wherein the high side switches are SCR devices, and the low side switches are insulated gate bipolar transistors.

6. The method of claim 1, wherein the H-bridge includes first and second low side switches, wherein the control signal is applied to one of the first or second low side switch.

7. The method of claim 1, wherein the device includes a power capacitor for providing signal to apply cardiac stimulus, wherein the method further includes charging the power capacitor to a predetermined level assured to maintain constant current when operating in a current controlled mode for a predetermined duration of time.