Arrhythmia detection with spatially differentiating epicardial sensors: signal processing

A system of three tripolar epicardial electrodes in a triangular configuration was acutely implanted in two dogs and chronically implanted in two more dogs. Electrograms were obtained during normal sinus rhythm (NSR), rapid ventricular pacing (VP) and artificially induced ventricular fibrillation (VF). The maximum of the time derivative was assumed to correspond to the moment of activation at the recording site. The delays between moments of activation were analyzed for each rhythm for each animal. Similar data sets were obtained from the two chronically implanted animals at 6 and 12 weeks. The sequences of activation were found to be reasonable stable for each rhythm, for each animal with respect to time. The method of activation delays suggests simple but effective algorithms for the classification of arrhythmias and a rapid method for the recognition of VF.