Patent ID: 8428714

Claim:
An active implantable medical device such as a cardiac prosthesis for pacing, resynchronization and/or defibrillation, comprising: Means ( 16 ) for collecting right atrial depolarizations; Means ( 18 ) for collecting left atrial depolarizations, and Means ( 18 ) for delivering left atrial pacing pulses, A contraction sensor ( 20 ), having a signal representative of movement produced by contractions of a myocardium; Means for analyzing said signal and determining therein an occurrence of a left atrial contraction, temporally distinguishable from a ventricular contraction for the same cardiac cycle; Means for identifying and applying to the means for delivering left atrial pacing pulses an interatrial delay between the collection of a right atrial depolarization and the delivery of a left atrial pacing pulse, Wherein the means for identifying and applying further comprises: Means for determining an absence of a determined left atrial contraction in said signal, and for iteratively reducing the interatrial delay during successive cardiac cycles from an initial value to an adjustment value corresponding to the means for analyzing determining an occurrence of a left atrial contraction and for maintaining the interatrial delay at said adjustment value as long as the means for analyzing continues to determine in said signal a left atrial contraction so as to restore a diastolic function of a patient.