The Use of an Internal Pacemaker in the Treatment of Cardiac Arrest and Slow Heart Rates

The purpose of this presentation is to discuss our experience in the use of an internal pacemaker for increasing cardiac rhythmicity in the presence of slow heart rates and for restoring cardiac beating during cardiac arrest. The artificial pacemakers available at the present time for cardiac stimulation include the Zoll External Pacemaker, 1-6 which has had several counterparts, and a number of internal pacemakers. With the external pacemaker, the stimulating electrodes are placed over the chest wall and deliver electric impulses with currents from 50 to 200 ma. and voltages from 20 to 100 volts. Recently, various internal pacemakers have been developed 7-11 which have been used successfully in animals and in human subjects. In these internal pacemakers, which include transistor models, the stimulating wire is directly attached to the heart muscle. In addition, the voltage source of the external pacemaker may be reduced so that it, too, may be