Patent ID: 7623921
Filing Date: 2009-11-24
Classification: A61N

Abstract:
1. A cardiac pacemaker, comprising: a plurality of electrodes disposable near a heart chamber; a plurality of pacing channels, wherein each such channel includes a pulse generator connectable to a selected electrode; a controller for controlling the operation of the pacemaker; an evoked response sensing channel comprising a sense amplifier for sensing an evoked response generated after a pacing pulse; a switching circuit operable by the controller for configuring a pacing channel or the evoked response sensing channel with a particular electrode; a telemetry interface; wherein the controller is programmed to perform a capture verification test upon receiving a command via the telemetry interface to test the sensing/pacing channel for presence or loss of capture, the capture verification test being performed by configuring the evoked response sensing channel with a particular electrode specified for the particular pacing channel to be tested via the switching circuit and sensing whether an evoked response occurs during a capture detection window following the output of a pacing pulse; and, wherein the controller is programmed to determine a pacing threshold of a sensing/pacing channel upon receiving a command via the telemetry interface by: a) performing a capture verification test on the channel; b) lowering a pacing pulse energy by a specified amount if capture was present during the preceding capture verification test and raising a pacing pulse energy by a specified amount if capture was absent during the preceding capture verification test; c) repeating the capture verification test with the raised or lowered pacing pulse energy; and, d) determining the pacing threshold as the unlowered pacing pulse energy if the pacing pulse energy was lowered at step b and a loss of capture occurred during the repeated capture verification test, and repeating steps b through d otherwise.