Patent ID: 8554319

Claim:
An active implantable medical device of cardiac stimulation, resynchronization and/or defibrillation prosthetic type, comprising: means for providing an atrial pacing, including an antitachycardia atrial pacing therapy, by delivering an atrial pacing pulse to an atrium; a sensor of mechanical activity having an output mechanical activity signal representative of movements produced by contractions of a ventricular cavity; means for detecting an occurrence of spontaneous atrial events (P); means for detecting ventricular activity, comprising: primary means for detecting an electrical potential representative of a spontaneous ventricular depolarization (R); auxiliary means for determining in the mechanical activity signal a peak component associated with a mechanical ventricular contraction; and an atrial post-pacing refractory period during which ventricular electrical activity detection is blocked; means for calculating a ventricular escape interval (IE); and means for providing an antibradycardia ventricular pacing therapy in an absence of a detected spontaneous ventricular event (R) after said calculated ventricular escape interval (IE); wherein the means for calculating the escape interval comprises: means for calculating a first value of escape interval (IE RR ) from the successive moments of potential occurrence of spontaneous ventricular depolarization (R) detected by the primary means; means for calculating a second value of escape interval (IE PEA ) from the successive instants of occurrence of the peaks detected by the auxiliary means, and means for selecting the second value of escape interval as the calculated ventricular escape interval in response to a delivery of an antitachycardia atrial pacing therapy.