Patent ID: 7996083

Claim:
A device comprising: an atrial sensing channel for incorporating one or more intracardiac electrodes adaptable for disposition near an atrium in order to generate an atrial electrogram; a ventricular sensing channel for incorporating one or more intracardiac electrodes adaptable for disposition near a ventricle in order to generate a ventricular electrogram; a pacing channel for incorporating one or more intracardiac electrodes adaptable for disposition near a ventricle or atrium and for delivering pacing pulses thereto; a far-field sensing channel incorporating at least two far-field electrodes adaptable for disposition in order to generate a far-field electrogram that reflects activity in both the atria and ventricles; a controller interfaced to the sensing channels and programmed with instructions for: upon delivery of a pacing pulse, disabling the atrial and ventricular sensing channels for a blanking interval on the order of 15-20 ms and disabling the far-field sensing channel for a blanking interval on the order of 1-2 ms; detecting a P-wave if two conditions are simultaneously met: 1) the atrial electrogram exceeds a specified atrial channel threshold, and 2) the far-field electrogram exceeds a specified far-field atrial threshold; detecting an R-wave if two conditions are simultaneously met: 1) the ventricular electrogram exceeds a specified ventricular channel threshold, and 2) the far-field electrogram exceeds a specified far-field ventricular threshold; wherein the far-field ventricular threshold is higher than the far-field atrial threshold; and, detecting an arrhythmia when the intervals between detected P-waves or between detected R-waves meets a specified rate criterion.