CPC A61N 1/37512 (2017.08) [A61B 5/0006 (2013.01); A61B 5/024 (2013.01); A61B 5/02116 (2013.01); A61B 5/02125 (2013.01); A61B 5/721 (2013.01); A61B 5/7282 (2013.01); A61N 1/3682 (2013.01); A61N 1/36175 (2013.01); A61N 1/36843 (2017.08)] | 39 Claims |
1. A pacemaker comprising:
a pulse generator configured to generate pacing pulses;
a sensing circuit comprising an R-wave detector for sensing R-waves from a cardiac electrical signal;
a motion sensor configured to produce a motion signal comprising an atrial event signal corresponding to an atrial systolic event; and
a control circuit coupled to the motion sensor and the pulse generator and configured to:
identify a plurality of ventricular electrical events, wherein each of the plurality of ventricular electrical events is one of an R-wave sensed by the sensing circuit or a ventricular pacing pulse generated by the pulse generator;
following each of at least a portion of the plurality of ventricular electrical events, set a sensing window;
determine a feature of the motion signal during each of the sensing windows by determining a latest crossing time of a first threshold amplitude by the motion signal during each of the sensing windows;
set an atrial event sensing parameter by setting an ending time of a passive ventricular filling window based on the determined features;
sense the atrial systolic event based on the atrial event sensing parameter; and
produce an atrial sensed event signal in response to sensing the atrial systolic event.
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