Cardiac pacemaker system for usage in combination with an implantable cardioverter-defibrillator
A cardiac pacing system comprising one or more leadless cardiac pacemakers configured for implantation in electrical contact with a cardiac chamber and configured to perform cardiac pacing functions in combination with a co-implanted implantable cardioverter-defibrillator (ICD). The leadless cardiac pacemaker comprises at least two leadless electrodes configured for delivering cardiac pacing pulses, sensing evoked and/or natural cardiac electrical signals, and bidirectionally communicating with the co-implanted ICD.
1. A method of operating a cardiac pacing system comprising:
performing cardiac pacing functions in at least one pacemaker in combination with a co-implanted cardioverter-defibrillator (ICD) comprising:
delivering cardiac pacing pulses;
sensing evoked and/or natural cardiac electrical signals;
bidirectionally communicating among the co-implanted ICD and/or at least one pacemaker of a plurality of pacemakers;
communicating a code that signifies occurrence of sensed cardiac electrical signals and/or delivered pacing pulses, identifying an event type and/or location;
waiting in an atrial pacemaker for an earliest occurring event of a plurality of events comprising a sensed atrial heartbeat, a communication of a signal marking a heartbeat at a ventricular pacemaker, or timeout of an escape interval;
responding to the sensed atrial heartbeat by generating an atrial pacing pulse signaling to at least one pacemaker of the pacemaker plurality and optionally to the co-implanted ICD that an atrial heartbeat has occurred and that encodes the atrial pacing pulse with a code signifying an atrial location and a sensed event type;
timing a predetermined atrial-to-atrial escape interval beginning at delivery of an atrial pacing pulse; responding to timeout of an escape interval by delivering an atrial pacing pulse, causing an atrial heartbeat; and
encoding the atrial pacing pulse with paced type and atrial location of an atrial heartbeat event.
2. The method according to claim 1 further comprising:
detecting at the atrial pacemaker a signal originating from a co-implanted ventricular pacemaker;
examining an elapsed amount of the atrial-to-atrial escape interval since a most recent atrial heartbeat;
determining whether the signal originating from the co-implanted ventricular pacemaker is premature;
in absence of a premature signal waiting for an event with no effect on atrial pacing;
for a premature signal restarting a ventricle-to-atrium escape interval that is shorter than the atrial-to-atrial escape interval and representative of a typical time from a ventricular beat to a next atrial beat in sinus rhythm;
responding to timeout of an escape interval by delivering an atrial pacing pulse, causing an atrial heartbeat; and
encoding the atrial pacing pulse with paced type and atrial location of an atrial heartbeat event.
3. The method according to claim 2 further comprising:
waiting in a right-ventricular pacemaker for an earliest occurring event of a plurality of events comprising a sensed right-ventricular heartbeat, a communication of a signal marking a heartbeat at an atrial pacemaker, and timeout of an escape interval;
responding to the sensed right-ventricular heartbeat by generating a right-ventricular pacing pulse that signals to at least one pacemaker of the pacemaker plurality and optionally to the co-implanted ICD that a right-ventricular heartbeat has occurred and that encodes the right-ventricular pacing pulse with a code signifying a right-ventricular location;
timing a predetermined right ventricular-to-right ventricular escape interval;
responding to timeout of an escape interval by delivering a right ventricular pacing pulse, causing a right ventricular heartbeat; and
encoding the right ventricular pacing pulse with paced type and right-ventricular location of a right ventricular heartbeat event.
4. The method according to claim 3 further comprising:
detecting in a right-ventricular pacemaker a signal originating from a co-implanted atrial pacemaker;
examining an elapsed amount of the ventricular-to-ventricular escape interval since a most recent right-ventricular heartbeat;
determining whether the signal originating from the co-implanted atrial pacemaker is premature;
for a premature signal waiting for an event with no effect on ventricular pacing;
in absence of a premature signal starting a right atrium to right ventricular (AV) escape interval that is representative of a typical time from an atrial beat to a right-ventricular beat in sinus rhythm;
responding to timeout of an escape interval by delivering a right ventricular pacing pulse, causing a right ventricular heartbeat; and
encoding the right ventricular pacing pulse with paced type and right-ventricular location of a right ventricular heartbeat event.
5. The method according to claim 2 further comprising:
waiting at a left-ventricular pacemaker for an earliest occurring event of a plurality of events comprising a communication of a signal marking a heartbeat at an atrial pacemaker and timeout of a left ventricular escape interval;
responding to timeout of the left ventricular escape interval by delivering a left ventricular pacing pulse, causing a left ventricular heartbeat; and
encoding the left ventricular pacing pulse with paced type and left ventricular location of a left ventricular heartbeat event.
6. The method according to claim 2 further comprising:
waiting at a left-ventricular leadless cardiac pacemaker for an earliest occurring event of a plurality of events comprising a communication of a signal marking a heartbeat at an atrial pacemaker and timeout of a left ventricular escape interval;
responding to the sensed communication of a pacing pulse marking a heartbeat at an atrialleadless cardiac pacemaker by examining an elapsed amount of the atrial-to-atrial escape interval since a most recent atrial heartbeat;
determining whether the signal originating from the co-implanted ventricular leadless cardiac pacemaker is premature;
for a premature signal restarting a ventricle-to-atrium escape interval that is shorter than the atrial-to-atrial escape interval and representative of a typical time from a ventricular beat to a next atrial beat in sinus rhythm;
responding to timeout of an escape interval by delivering an atrial pacing pulse, causing an atrial heartbeat; and
encoding the atrial pacing pulse with paced type and atrial location of an atrial heartbeat event.
7. The method of claim 1 further comprising receiving the code using at least one pacemaker of a plurality of pacemakers;
decoding the information using at least one pacemaker of a plurality of pacemakers; and
reacting to the information decoded depending on a location of the receiving pacemaker and a predetermined system functionality.
8. The method of claim 1 wherein delivering cardiac pacing pulses comprises delivering cardiac pacing pulses using two or more electrodes of the at least one pacemaker of a plurality of pacemakers, wherein the at least one pacemaker is a leadless pacemaker, and wherein issuing and communicating a code comprises generating a coded pulse using a pulse generator of the leadless pacemaker and delivering the coded pulse using the same electrodes of the leadless pacemaker used to deliver cardiac pacing pulses.
9. The method of claim 1 , further comprising:
issuing a code that signifies occurrence of sensed cardiac electrical signals or delivered pacing pulses, wherein the code identifies an event type and location; and
generating a coded pulse using the code, wherein the at least one pacemaker of a plurality of pacemakers is a leadless pacemaker, and wherein communicating the code comprises delivering the coded pulse using electrodes of the leadless pacemaker.
10. The method of claim 1 , wherein the ICD is a subcutaneous implantable cardioverter-defibrillator (SICD).