The combined use of an artificial pacemaker and the insertion of a myocardial electrode has been described and demonstrated to be an effective method of controlling the heart rate at low voltages and low current amplitudes when complete heart block is present. The cardiac output and mean aortic pressures of dogs have been restored to preblock levels throngh the application of electric stimuli applied directly to the myocardium. No complications from insertion of removal of the wire in the heart wall were observed. The heart rates of 18 patients with surgically induced complete atrioventricular dissociation have been successfully managed by the method described with an important reduction in the mortality associated with this complication of open heart surgery.