The device has a collecting unit to continuously collect endocardiac acceleration signal on a sequence of cardiac cycles. A selection unit applies a series of validation criteria to sub-signals and components associated with the sequence of cycles. A detection unit detects (24) status change of a patient and occurrence of predetermined activity of the patient. Dynamic adaptation blocks dynamically adapt a signal processing unit to modify one of the criteria and/or a parameter of the processing unit based on the detection of status change and the occurrence of activity of the patient. The status change or the predetermined activity of the patient is chosen from a group comprising increase of heart rate, instability of heart rate, decreasing of amplitude of peak endocardial acceleration, respiratory rate, apnea detection and application of external command. The parameter of the processing unit is chosen from a group comprising a number of cycles of the collected and processed sequence, a step separating two successive processed and collected sequences and duration of analysis window of each component. The validation criteria are chosen from a group comprising minimum threshold for a correlation coefficient with respect to a reference cycle, maximum threshold for time lag with respect to the reference cycle, minimum number of cycles for a sequence of cardiac cycles retained by the selection unit and selection of only sub-signals whose components correspond to validation criteria, in case of components isolated from the sub-signals.Le dispositif comprend des moyens de recueil en continu dun signal daccélération endocardiaque EA avec : découpage en sous-signaux EA chacun sur la durée dun cycle cardiaque séparation des composante EA1 et EA2 intercorrélation entre les sous-signaux EA de chaque composante et recalage temporel par rapport à un cycle de référence application dune série de critères de validation et moyennage pour délivrer en sortie un signal EA global moye
