Input switching in a ventricular intracardiac pacemaker

An intracardiac pacemaker system, comprising:

• a ventricular intracardiac pacemaker;
• and
• a second implantable device configured to broadcast atrial event signals to the ventricular intracardiac pacemaker,
• the ventricular intracardiac pacemaker comprising:
• a first pulse generator configured to generate and deliver pacing pulses to a ventricle of a patient's heart via a first plurality of electrodes coupled to the ventricular intracardiac pacemaker;
• a first sensing circuit configured to produce physiological atrial event signals;
• a receiving circuit configured to receive the broadcast atrial event signals from the second implantable medical device;
• a first control circuit coupled to the pulse generator, the first sensing circuit, and the receiving circuit, the first control circuit configured to:
• select a first atrial event input as the physiological atrial event signals that do not require the second implantable device to broadcast or generate atrial event signals;
• detect first atrial events from the selected first atrial event input;
• determine if input switching criteria are met;
• switch from the first atrial event input to a second atrial event input in response to the input switching criteria being met, the second atrial event input being the broadcast atrial event signals;
• detect second atrial events from the second atrial event input;
• and
• set an atrioventricular (AV) pacing interval in response to detecting each of the first atrial events and the second atrial events for controlling the first pulse generator to deliver the ventricular pacing pulses.