Patent ID: 6496730
Filing Date: 2002-12-17
Classification: A61N

Abstract:
In an implantable medical device for cardiac pacing, a method of delivering triggered pacing pulses to the heart comprising the steps of:locating first and second pace/sense electrodes at first and second spaced apart sites of the heart; sensing spontaneous cardiac depolarizations traversing one of the other of the first and second pace/sense electrodes and providing a sense event signal; upon provision of a sense event signal that is characterized as non-refractory, starting and timing out a pacing escape interval; upon provision of a non-refractory sense event signal during the time-out of the pacing escape interval, terminating and restarting the pacing escape interval, and commencing and timing out a post-event time period adapted to be extended upon a sense event signal provided while it is being timed out and a conditional refractory period; and in response to provision of a sense event signal during the conditional refractory period, characterizing the sense event signal as a refractory sense event signal incapable of restarting the pacing escape interval, terminating the conditional refractory period, and timing out the remaining period of the post-event time period without extending it, whereby the undue prolongation of the post-event period due to a sense event resulting from sensing of delayed propagation of a single heart chamber depolarization between the first and second pace/sense electrodes is avoided and legitimate right or left heart chamber sense event signals occurring thereafter are not characterized as refractory and are able to restart the pacing escape interval.