Drift compensation in multi-chamber leadless pacemaker system

A leadless pacemaker (LP) configured to communicate with a second LP using implant-to-implant (i2i) communication, wherein the LP is configured to perform pacing of a first cardiac chamber, and wherein the second LP is configured to perform pacing of a second cardiac chamber, the LP comprising:

• a receiver configured to receive event messages from the second LP using i2i communication;
• a plurality of electrodes;
• a memory;
• a pulse generator configured to deliver pacing pulses using at least two of the plurality of electrodes;
• and
• a controller communicatively coupled to the receiver, the pulse generator, and the memory;
• the controller configured to:
• during a first period of time, during which event messages are received by the receiver from the second LP using i2i communication, control the pulse generator to time pacing of the first cardiac chamber based on the event messages received by the receiver from the second LP using i2i communication so that atrioventricular (AV) synchrony is maintained during the first period of time;
• during the first period of time, during which the event messages are received by the receiver from the second LP using i2i communication, determine and store one or more count values in the memory;
• determine a compensation offset based on at least one of the one or more count values determined and stored during the first period of time, wherein the compensation offset is indicative of a drift between timing circuitry of the LP and timing circuitry of the second LP;
• and
• during a second period of time, during which event messages are not received by the receiver from the second LP, control the pulse generator to time pacing of the first cardiac chamber based on the compensation offset, to thereby compensate for the drift between the timing circuitry of the LP and the timing circuitry of the second LP so that the AV synchrony is maintained during the second period of time.

A multi-chamber leadless pacemaker system comprising:

• a first leadless pacemaker (LP);
• and
• a second LP;
• the first LP configured to communicate with the second LP using implant-to-implant (i2i) communication;
• the first LP configured to perform pacing of the first cardiac chamber;
• and
• the second LP configured to perform pacing of the second cardiac chamber,
• the second LP comprising:
• a plurality of electrodes;
• a pulse generator configured to deliver pacing pulses using at least two of the plurality of electrodes and transmit event messages to the first LP using i2i communication;
• and
• a controller communicatively coupled to the pulse generator;
• the first LP comprising:
• a receiver configured to receive event messages from the second LP using i2i communication;
• a plurality of electrodes;
• a memory;
• a pulse generator configured to deliver pacing pulses using at least two of the plurality of electrodes;
• and
• a controller communicatively coupled to the receiver, the pulse generator, and the memory;
• the controller of the first LP configured to:
• during a first period of time, during which event messages are received by the receiver from the second LP using i2i communication, control the pulse generator to time pacing of the first cardiac chamber based on the event messages received by the receiver from the second LP using i2i communication so that atrioventricular (AV) synchrony is maintained during the first period of time;
• during the first period of time, during which the event messages are received by the receiver from the second LP using i2i communication, determine and store one or more count values in the memory;
• determine a compensation offset based on at least one of the one or more count values determined and stored during the first period of time, wherein the compensation offset is indicative of a drift between timing circuitry of the first LP and timing circuitry of the second LP;
• and
• during a second period of time, during which event messages are not received by the receiver from the second LP, control the pulse generator to time pacing of the second cardiac chamber based on the compensation offset, to thereby compensate for the drift between the timing circuitry of the first LP and the timing circuitry of the second LP so that the AV synchrony is maintained during the second period of time.