CPC A61N 1/36578 (2013.01) [A61B 5/1102 (2013.01); A61B 5/352 (2021.01); A61B 5/4836 (2013.01); A61B 5/686 (2013.01); A61B 5/7282 (2013.01); A61N 1/3682 (2013.01); A61N 1/3756 (2013.01); A61N 1/37205 (2013.01); A61N 1/0573 (2013.01); A61N 1/37217 (2013.01)] | 21 Claims |
1. An implantable medical device, comprising:
a motion sensor configured to produce a motion signal;
a control circuit configured to, for each of a plurality of cardiac cycles:
set a refractory period having an expiration time after a first ventricular diastolic event signal of the motion signal and before a second ventricular diastolic event signal of the motion signal, the second ventricular diastolic event signal being a ventricular passive filling event signal;
determine that the motion signal crosses a threshold amplitude after the expiration time of the refractory period;
detect an atrial event signal in response to the motion signal crossing the threshold amplitude; and
a pulse generator configured to generate a ventricular pacing pulse in response to detecting the atrial event signal.
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