An implantable cardiac stimulation device provides selective atrial pacing
upon detection of a premature ventricular complex (PVC). The device
comprises a premature ventricular complex detector that detects premature
complexes of the heart, and a sensing circuit that senses atrial events.
The device further comprises a P wave discriminator that identifies an
atrial event sensed by the sensing circuit following detection of a
premature ventricular complex as one of a retrograde P wave and a normal
sinus P wave, and an atrial pulse generator that delivers an atrial
pacing pulse responsive to the discriminator identifying an atrial event
sensed by the sensing circuit following detection of a premature
ventricular complex as a retrograde P wave.