Patent ID: 7826898

Claim:
An implantable cardiac stimulation device comprising: one or more electrodes adapted for coupling with cardiac tissue; a pulse generator adapted to output pacing pulses to the electrodes; a converter adapted to sense cardiac polarizations through the electrodes; and a controller coupled to the pulse generator and the converter and having code stored therein that defines a base inhibit interval and an extended inhibit interval, the controller programmed to: periodically control the pulse generator to deliver pacing pulses upon expiration of the extended inhibit interval while processing the cardiac polarizations sensed by the converter to determine if the cardiac rate has increased by a threshold amount and if the cardiac rate has increased by a threshold amount, to detect for premature contractions; control the pulse generator to deliver pacing pulses upon expiration of the base inhibit interval if the cardiac rate has increased by a threshold amount and no premature contractions are detected; and control the pulse generator to deliver pacing pulses upon expiration of the extended inhibit interval if the cardiac rate has increased by a threshold amount and one or more premature contractions are detected.