1. An active medical device, comprising: a stimulator coupled to a first lead configured to deliver electrical stimulation pulses to at least one heart chamber of a patient; and a circuit for collecting the electrical activity of the heart, wherein the circuit generates at least two distinct readings from two separate endocardial electrogram signals concurrently collected, wherein the circuit is configured to perform a capture test to detect the occurrence of a depolarization wave induced by the stimulation of the heart chamber, wherein the circuit performs the capture test by determining a non-temporal two dimensional characteristic representative of the cardiac cycle to be analyzed by pairing the variations of the two distinct readings from the two separate endocardial electrogram signals, wherein the capture test comprises determining whether the non-temporal two-dimensional characteristic is contained within a predetermined two dimensional domain.