Active implantable medical device, in particular a pacemaker, defibrillator and/or cardiovertor of the multisite type providing resynchronization of the ventricles

An active implantable medical device of the multisite type to be connected to electrodes placed in at least one left cardiac site and at least one right cardiac site, said device having a cardiac signal collection circuit for connection to at least one of said electrodes to detect a depolarization potential, and a stimulation circuit to apply stimulation pulses to at least two of said sites through corresponding electrodes, said device comprising means for resynchronization of ventricular contractions, including:

• (a) means for establishing a delay between a time of application of a stimulation pulse to a right ventricle (RV) and a stimulation pulse to a left ventricle (LV);
• (b) means for determining and analyzing a parameter of a degree of desynchronization between contraction of said left and right ventricles for a cardiac cycle, said parameter indicating a variation between left and right ventricular systole;
• and
• (c) means for varying the delay in a direction of a reduction of the parameter of the degree of desynchronization.