A device produces at least two distinct temporal components (Vbip, Vuni) from two separate endocardial electrogram EGM signals concurrently collected in the same cavity. A 2D non-temporal characteristic is determined from the variations of one of the temporal components (Vuni) versus the other (Vbip). The analysis of this characteristic allows detection of the possible presence of an anodal stimulation, causing a depolarization in a second cavity after stimulation delivered to a first heart chamber, opposite to the first. One possibility is to proceed by observing whether the non-temporal 2D characteristic is included or not within a predetermined domain defined in a coordinate frame corresponding to the space of the two temporal components.
