A late potential detecting system has an implantable medical device connected to at least one cardiac lead having implantable electrodes positioned at different sites of a ventricle myocardium. A sampling unit of the implantable medical device records electrogram samples for the different implantable electrodes to get different sample sets. The electrogram samples of the sample sets are time synchronized and magnitude potential representations of the potential data of the electrogram samples are determined. The magnitude potential representations of the time synchronized electrogram samples are then co-processed and used for determining a parameter that is indicative of any late potentials of the monitored ventricle.