An active implantable medical device, in particular a defibrillator/cardioverter,
with a sophisticated discrimination of atrial fibrillations. This device is able
to deliver therapy for defibrillation, cardioversion, and/or ventricular and/or
atrial antitachycardiac pacing stimulation; sense the ventricular and atrial activity;
identify a suspicion of and confirm the presence of episodes of tachycardia in
the activity thus sensed; analyze the stability of detected RR intervals and the
stability of the associated PR intervals; and, in the event of a detection of stable
RR intervals and unstable PR intervals, discriminate between atrial fibrillation
with fast ventricular rhythm and atrial fibrillation with ventricular tachycardia,
and to control delivery of a differentiated therapy according to one case or the
other. A bi-tachycardia discrimination also can be made.
