Detection of evoked post-stimulation potentials, in particular atrial potentials in an active implantable medical device such as cardiac pacemaker, defibrillator, cardiovertor or multisite device

An active implantable medical device, in particular a cardiac pacemaker, defibrillator, cardiovertor or multisite device, comprising:

• a terminal having a receptacle for receiving an intracardiac electrode of an implanted probe, said probe having a distal end located in a first cardiac cavity;
• at least one circuit for delivering a stimulation pulse to said terminal;
• means for applying a stimulation pulse to said terminal for delivery to said first cardiac cavity;
• a discharging circuit coupled to said terminal having a switch operable to short-circuit for a discharge period said terminal;
• at least one circuit for detecting at said terminal electronic signals corresponding to spontaneous potential appearing in said first cardiac cavity, including
• an amplifier having an input coupled to said terminal and an output, and
• a blanking circuit having a switch able to temporarily uncouple the terminal from the amplifier input;
• and
• a sequencer control circuit to, successively:
• activate the discharging circuit in response to an application of the stimulation pulse, throughout the discharge period, and
• activate the blanking circuit for a first time throughout a detected stimulation pulse,
• activate the discharging circuit with a delay after the application of the stimulation pulse,
• inhibit the blanking circuit for a listening period, said listening period comprising at least a part of the said delay, wherein during this period of listening, the amplifier detects at said terminal, electric signals corresponding to spontaneous post-stimulation potentials in the first cavity;
• and
• activate the blanking circuit a second time after the listening period, throughout said discharge period.