Patent ID: 7363081

Claim:
In an implantable cardiac stimulation device for implant within a patient, a system comprising: a pacing unit for delivering primary pacing pulses to the heart; a pulse capture detection unit detecting loss of capture of primary pacing pulses; a backup pulse unit delivering backup pulses to the heart upon detection of a loss of capture of a primary pacing pulse; wherein the capture detection unit detects loss of capture of backup pacing pulses; a capture-based tachycardia detection unit detecting a tachycardia based upon loss of capture of backup pacing pulses as detected by the capture detection unit; an antitachycardia pacing (ATP) therapy unit operative to deliver antitachycardia pacing therapy to the heart upon the detection of tachycardia by the tachycardia detection unit; and a premature atrial contraction (PAC) detection unit; wherein a control unit is operative to suspend preventive overdrive pacing and to activate the ATP unit upon the detection of a loss of capture of a backup pulse delivered subsequent to detection of a PAC during preventive overdrive pacing.