Chest wall stimulation by pin electrodes in patients with implanted demand pacemakers

Summary In order that we might inhibit their implanted units, 30 patients with permanent R-wave inhibited demand pacemakers underwent chest wall stimulation by impulses delivered from an external pacemaker, first through skin electrodes and then, in the identical positions, through fine platinum subcutaneous pin electrodes of the type used in electroencephalography. A comparison of the suppression characteristics of these electrodes is reported. Both techniques were uniformly successful at low impulse amplitude for the five unipolar pacemakers. In bipolar pacemakers, suppression was achieved in 24 of 25 by pin electrodes, in nine of 25 by skin electrodes, and in one by neither. Of the nine bipolar pacemakers suppressed by both methods, six needed more current amplitude for skin electrodes, while three needed equal current amplitude. In 27 patients the spontaneous rhythm and QRST configuration were determined. One patient had P-waves only and one had no spontaneous electrical activity. Chest wall stimulation through pin electrodes provides a quick, safe, and predictable means of suppressing the R-wave inhibited demand pacemaker.