Device for adaptive processing of an endocardial acceleration signal. The device continuously collects an endocardial acceleration EA signal and divides it into EA sub-signals, each over the duration of one cardiac cycle. The EA sub-signals are separated into the EA1 and EA2 components. A cross-correlation between the EA sub-signals of each component and a time calibration compared to a reference cycle, and a series of validation criteria is applied. The result is an average overall EA signal for a cycle. A change in the patients condition or an occurrence of a predetermined event in the patient is detected (24) and, as a result there is dynamic adaptation of at least one of said validation criteria and/or at least one of the pre-processing parameters for calculating the EA signal average.