Methods and systems for detecting atrial contraction timing fiducials during ventricular filling from a ventricularly implanted leadless cardiac pacemaker

An implantable medical device configured to sense cardiac activity and to deliver pacing therapy to a patient's heart, the implantable medical device comprising:

• a housing;
• a first electrode secured relative to the housing and exposed to the environment outside of the housing;
• a second electrode secured relative to the housing and exposed to the environment outside of the housing;
• a sensing module disposed within the housing, the sensing module configured to:
• sense during passive ventricular filling of the patient's heart at least one of a pressure, impedance, strain, sound, rotation, acceleration, voltage, and flow;
• detect an artifact;
• and
• identify an atrial event based, at least in part, on the detected artifact;
• and
• circuitry in the housing operatively coupled to the first electrode, the second electrode, and the sensing module, the circuitry configured to deliver a ventricular pacing pulse to the patient's heart via the first electrode and the second electrode, wherein a timing of the ventricular pacing pulse is dependent, at least in part, on the timing of the identified atrial event.

An implantable medical device configured to sense cardiac activity and to deliver pacing therapy to a patient's heart, the implantable medical device comprising:

• a housing;
• a first electrode secured relative to the housing and exposed to the environment outside of the housing;
• a second electrode secured relative to the housing and exposed to the environment outside of the housing;
• a sensing module disposed within the housing, the sensing module configured to:
• sense during active ventricular filling of the patient's heart at least one of a pressure, impedance, strain, sound, rotation, acceleration, voltage,
• and flow;
• detect an artifact;
• and
• identify an atrial event based, at least in part, on the detected artifact;
• and circuitry in the housing operatively coupled to the first electrode, the second electrode, and the sensing module, the circuitry is configured to deliver a ventricular pacing therapy to the patient's heart via the first electrode and the second electrode, wherein the ventricular pacing therapy is time dependent, at least in part, on the identified atrial event.