Patent ID: 7400922

Claim:
An active implantable medical device comprising: means for detecting a spontaneous depolarization potential in each of the right ventricle and the left ventricle; means for detecting a spontaneous depolarization in the right atrium and eventually in the left atrium; means for delivering to each of the right ventricle and the left ventricle impulses of stimulation; means for establishing an adjustable inter-ventricular delay between a stimulation impulse delivered to the right ventricle and a stimulation impulse delivered to the left ventricle during a same cardiac cycle; means for operating the implantable multi-site pacemaker in a ventricular resynchronization pacing mode that includes a test for capture at both the left and right ventricles; means for detecting a loss of capture at either the left or right ventricle; means for switching immediately to an AAI pacing mode following a detected loss of capture at either the left or right ventricle; means for detecting whether capture has resumed at both the left and right ventricle; and means for switching back to the ventricular resynchronization pacing mode if capture has resumed at both the left and right ventricle.