A medical device for characterizing the cardiac status of a patient equipped with a bi-ventricular pacing active implant device. The implant collects an endocardiac acceleration signal and searches for an optimal pacing configuration. This latter tests a plurality of different pacing configurations and delivers for each tested configuration parameters derived from the endocardiac acceleration peak (PEA). The device derives a patient clinical status from those parameters, the indication being representative of the patient's response to the cardiac resynchronization therapy. Those parameters include: the possibility to automatically get or not a valid optimal AV Delay among all the biventricular pacing configurations； a factor indicating the character sigmoid of the PEA/AVD characteristic； the average value of the PEA for the various configurations； and the PEA signal/noise ratio. The active implantable medical device includes control software and processes for executing the characterizing functionality described.
