Defibrillation pacing circuitry

Patent metadata

Field	Value
Publication number	US-9522284-B2
Application number	US-201615051805-A
Country	US
Kind code	B2
Filing date	Feb 24, 2016
Priority date	Nov 5, 2001
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

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.

First claim

What is claimed is:

1. An implantable cardiac stimulus system comprising:
implantable electrodes for the delivery of electrical stimulus to a patient;
operational circuitry including at least an H-bridge circuit comprising a high side and a low side, wherein the H-bridge circuit comprises first and second legs connected between the high side and the low side thereof, wherein the first leg of the H-bridge circuit comprises first and second current switching elements and the second leg of the H-bridge circuit comprises third and fourth current switching elements, the H-bridge comprising output nodes for coupling to patient tissue via the implantable electrodes, wherein a first output node is located on the first leg between the first and second current switching elements and a second output node is located on the second leg between the third and fourth current switching elements, the operational circuitry further comprising a constant current circuit connected to the low side of the H-bridge circuit and
a canister for housing at least the battery and operational circuitry;
wherein the first and fourth current switching elements define a first pair of current switching elements;
wherein the operational circuitry is configured to select the first pair of current switching elements to generate a stimulus of a first polarity for application via the first and second output nodes; and
wherein the constant current circuit comprises a bypass switch and a pacing resistor in parallel with one another and coupled to the low side of the H-bridge;
wherein the operational circuitry is configured to close the bypass switch to deliver a defibrillation output, and to open the bypass switch to force current from the low side of the H-bridge through the pacing resistor to deliver a pacing output and
wherein the constant current circuit is configured to control operation of the fourth current switching element by monitoring a voltage across the pacing resistor during a stimulus of the first polarity to force the stimulus to be a substantially constant current pacing stimulus.

2. The implantable system of claim 1 wherein:
in the first leg of the H-bridge, the first current switching element links the high side of the H-bridge to the first output node and the second current switching element links the low side of the H-bridge to the first output node;
in the second leg of the H-bridge, the third current switching element links the high side of the H-bridge to the second output node and the fourth current switching element links the low side of the H-bridge to the second output node;
the constant current circuit includes an amplifier for generating a control signal output to the fourth switching element.

3. The implantable system of claim 2 wherein the operational circuitry is configured to generate the substantially constant current pacing therapy by applying a first voltage to the high side of the H-bridge, closing the first switch, and applying the control signal output to the fourth switch.

4. The implantable system of claim 3 wherein the operational circuitry further comprises a therapy circuit with a high power capacitor for use in delivering either pacing or defibrillator therapy, such that the first voltage is received from the high power capacitor.

Assignees

• Cameron Health Inc
• Cameron Health Inc

Inventors

• Ostroff Alan H

Classifications

• A61N1/362

  Heart stimulators (heart defibrillators A61N1/39) · CPC title

• A61N1/3912 Primary

  Output circuitry therefor, e.g. switches · CPC title

• A61N1/39622

  Pacing therapy · CPC title

• A61N1/3962 Primary

  in combination with another heart therapy · CPC title