Methods and systems for detecting atrial contraction timing fiducials and determining a cardiac interval from a ventricularly implanted leadless cardiac pacemaker

A leadless cardiac pacemaker (LCP) configured to sense cardiac activity and to deliver pacing therapy to a patient's heart, the LCP 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 responsive to the environment outside of the housing, the sensing module including one or more of a pressure measurement module and an acoustic measurement module, the sensing module configured to gather information suitable for determining one or more cardiac intervals associated with the patient's heart;
• a control module operatively coupled to the first electrode, the second electrode, and the sensing module, the control module is configured to:
• process information gathered by the sensing module to identify the one or more cardiac intervals associated with the patient's heart;
• and
• deliver a pacing pulse to the patient's heart via the first electrode and the second electrode, wherein the pacing pulse is delivered at a time that is based, at least in part, on the identified one or more cardiac intervals.

A leadless cardiac pacemaker (LCP) configured to sense cardiac activity and to deliver pacing therapy to a patient's heart, the LCP 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 responsive to the environment outside of the housing, the sensing module including two or more sensing modules each for detecting a different event type, the two or more sensing modules including an electrogram measurement module for detecting electrical event types, and one or more of a pressure measurement module for detecting pressure event types and an acoustic measurement module for detecting acoustic event types, the sensing module configured to gather information suitable for determining one or more cardiac intervals associated with the patient's heart;
• a control module operatively coupled to the first electrode, the second electrode, and the sensing module, the control module is configured to:
• process information gathered by the sensing module to identify the one or more cardiac intervals associated with the patient's heart, wherein at least one cardiac interval begins with a detected first event type and ends with a detected second event type that is different from the detected first event type;
• and
• deliver a pacing pulse to the patient's heart via the first electrode and the second electrode, wherein the pacing pulse is delivered at a time that is based, at least in part, on the identified one or more cardiac intervals.