Patent ID: 8090434

Claim:
A method for classifying sense events in implantable devices using signals provided by an electrogram comprising: providing a template signal and a test signal from an intracardiac electrogram IEGM signal, an atrial electrogram AEGM signal, a ventricular electrogram VEGM signal, a surface electrocardiogram ECG signal, or a subcutaneous electrogram signal, the template signal and the test signal comprising samples having sample values; constructing at least one of a normal atrial sense AS template waveform from the AEGM signal that corresponds to normal intrinsic atrial depolarization; a normal ventricular sense VS template waveform from the VEGM signal that corresponds to antegrade conducted ventricular depolarization; a retrograde AS template waveform from the AEGM signal that corresponds to retrograde atrial depolarization; a normal right ventricular RV sense template that corresponds to normal intrinsic RV depolarization; a normal left ventricular LV sense template that corresponds to normal intrinsic LV depolarization; transforming at least the test signal into a representation of the test signal wherein the sample values of the test signal are integers; determining a correlation between the template signal and the test signal; differentiating the retrograde atrial depolarization from normal intrinsic atrial depolarization via said correlation by calculating for an AS event detected within a post-ventricular atrial refractory period PVARP a first correlation value by comparing a corresponding AEGM signal with the normal atrial sense AS template waveform; depending on the first correlation value, indicating the AS event as a normal intrinsic AS, or not, then calculating a second correlation value by comparing the corresponding AEGM signal with the retrograde AS template waveform; and, depending on the second correlation value indicating the AS event as a retrograde AS, or neither the normal intrinsic AS, nor the retrograde AS; and, classifying a sense event based on the correlation.