Pacing mode switching in a ventricular pacemaker

An intracardiac ventricular pacemaker comprising:

• a pulse generator configured to generate and deliver pacing pulses to a ventricle of a patient's heart via electrodes coupled to the pacemaker;
• a motion sensor configured to produce a motion signal;
• and
• a control circuit configured to receive the motion signal and communicate with the pulse generator, the control circuit configured to:
• detect an atrial systolic event from the motion signal;
• detect a ventricular diastolic event from the motion signal;
• operate in a selected one of an atrial-tracking ventricular pacing mode and a non-atrial tracking ventricular pacing mode;
• while operating in the selected one of the atrial-tracking ventricular pacing mode and the non-atrial tracking ventricular pacing mode, determine at least one motion signal metric based on a time interval from the ventricular diastolic event to the atrial systolic event;
• compare the at least one motion signal metric to pacing mode switching criteria;
• and
• responsive to the pacing mode switching criteria being satisfied, switch from the selected one of the non-atrial tracking pacing mode and the atrial tracking pacing mode to the other one of the non-atrial tracking pacing mode and the atrial tracking pacing mode for controlling the pacing pulses delivered by the pulse generator.

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

• 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;
• while operating in the selected one of the atrial-tracking ventricular pacing mode and the non-atrial tracking ventricular pacing mode, determining by a control circuit of the pacemaker at least one motion signal metric based on a rate of at least some of the detected atrial systolic events;
• determining a patient physical activity metric from the motion signal;
• setting a pacing mode switching threshold based on the patient physical activity metric;
• comparing the at least one motion signal metric to pacing mode switching criteria,
• wherein the comparing comprises comparing the rate of the at least some of the detected atrial systolic events to the pacing mode switching threshold;
• and
• responsive to the pacing mode switching criteria being satisfied, switching from the selected one of the non-atrial tracking pacing mode and the atrial tracking pacing mode to the other one of the non-atrial tracking pacing mode and the atrial tracking pacing mode for controlling ventricular pacing pulses delivered by the pacemaker.

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

• detecting a ventricular diastolic event from the motion signal;
• detecting an atrial systolic event from the motion signal;
• operating in a selected one of an atrial-tracking ventricular pacing mode and a non-atrial tracking ventricular pacing mode;
• while operating in the selected one of the atrial-tracking ventricular pacing mode and the non-atrial tracking ventricular pacing mode, determining the at least one motion signal metric based on a time interval from the ventricular diastolic event to the atrial systolic event;
• 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 pacing mode and the atrial tracking pacing mode to the other one of the non-atrial tracking pacing mode and the atrial tracking pacing mode for controlling ventricular pacing pulses delivered by the pacemaker.