Pacing mode switching in a ventricular pacemaker

A method performed by an intracardiac ventricular pacemaker having a motion sensor configured to produce a motion signal, the method comprising:

• receiving the motion signal by a control circuit of the pacemaker
• detecting atrial systolic events from the motion signal;
• operating in a selected one of an atrial-tracking ventricular pacing mode and a non-atrial tracking ventricular pacing mode, wherein operating in the atrial-tracking ventricular pacing mode comprises setting an atrioventricular pacing interval in response to detecting an atrial systolic event from the motion signal and controlling a pulse generator of the pacemaker to deliver a ventricular pacing pulse in response to the atrioventricular pacing interval expiring;
• while operating in the selected one of the atrial-tracking ventricular pacing mode and the non-atrial tracking ventricular pacing mode, determining from the motion signal at least one motion signal metric;
• comparing the at least one motion signal metric to pacing mode switching criteria;
• and
• responsive to the pacing mode switching criteria being satisfied, switching from the selected one of the non-atrial tracking ventricular pacing mode and the atrial-tracking ventricular pacing mode to the other one of the non-atrial tracking ventricular pacing mode and the atrial-tracking ventricular pacing mode.

A non-transitory, computer-readable medium storing a set of instructions, which, when executed by a control circuit of an intracardiac ventricular pacemaker having a motion sensor configured to produce a motion signal, cause the pacemaker to:

• detect atrial systolic events from the motion signal;
• operate in a selected one of an atrial-tracking ventricular pacing mode and a non-atrial tracking ventricular pacing mode, wherein operating in the atrial-tracking ventricular pacing mode comprises setting an atrioventricular pacing interval in response to detecting an atrial systolic event from the motion signal and controlling a pulse generator of the pacemaker to deliver a ventricular pacing pulse in response to the atrioventricular pacing interval expiring;
• while operating in the selected one of the atrial-tracking ventricular pacing mode and the non-atrial tracking ventricular pacing mode, determine from the motion signal at least one motion signal metric;
• compare the at least one motion signal metric to pacing mode switching criteria;
• and responsive to the pacing mode switching criteria being satisfied, switching from the selected one of the non-atrial tracking ventricular pacing mode and the atrial-tracking ventricular pacing mode to the other one of the non-atrial tracking ventricular pacing mode and the atrial-tracking ventricular pacing mode.