Implantable medical systems and methods used to detect, characterize or avoid atrial oversensing within an iegm

An implantable medical system comprising:

• one or more implantable electrodes that can be used for sensing and pacing;
• a sensing circuit configured to sense an intracardiac electrogram (IEGM) using at least one of the one or more implantable electrodes;
• one or more pulse generators;
• and
• a controller operatively coupled to the sensing circuit and the one or more pulse generators and configured to:
• cause sensing or pacing of a right atrium to thereby sense or pace an atrial event;
• detect potential atrial oversensing by detecting that a portion of the IEGM exceeds a specified sense threshold within a specified window within an atrioventricular delay (AVD) following the sensed or paced atrial event;
• determine an atrial event-to-threshold crossing interval corresponding to a length of time between the paced or sensed atrial event and a respective crossing of the specified sense threshold within the specified window within the AVD following the sensed or paced atrial event;
• specify an atrial oversensing avoidance (AOA) period based on the atrial event-to-threshold crossing interval, the AOA period corresponding to when atrial oversensing may occur following one or more further paced or sensed atrial events;
• and
• after the AOA period is specified, selectively cause use an atrial oversensing avoidance technique during one or more instances of the AOA period that follow the one or more further paced or sensed atrial events to thereby reduce a likelihood of atrial oversensing during the one or more instances of the AOA period.