Body Surface Isopotential Mapping of Permanent Cardiac Pacemaker Spike Amplitudes: A Noninvasive Method for Detecting and Localizing Insulation Failure

Cardiac pacing systems produce cardiac contractions by delivering electrical charges to the myocardium. Reliable cardiac pacing, and the longevity of pacemakers depends on the absence of electrical leaks. Electrical leaks often do not cause symptoms and if suspected, there are few methods which are able to identify their location and none suited to small or intermittent leaks. We surface mapped the pacemaker spike amplitudes over the pockets of 29 patients with unipolar pacemakers, several of which had suspected pacemaker leaks. For each patient, pacer voltage spikes were recorded with an optical ECG recorder from sixty-three positions on the skin over the pacemaker. The spike voltages were interpolated with a 2-D Fourier transform, contoured, and plotted by a computer. Electrical leaks were readily detected and their positions indicated by the resulting maps. The operative findings confirmed the map guided prediction in all six patients sent for pacemaker revision. Pacemaker spike amplitude surface mapping detects and locates pacing system insulation failures.