Causes of death in patients with complete heart block and aritificial pacemakers.

Abstract

The cause of death in 26 patients being treated with long-term pacing for chronic heart block, was analysed. The patients were paced by endocardial (19) or epicar-dial (7) systems for an average of 13.6 months (range[long dash]min.-54 months) before death. Necropsy included a study of the conducting tissues at 8 m intervals, and multiple blocks were examined from all valves and chambers. The coronary arteries were studied by a simple injection technique and serial blocks. The pacemaker systems were carefully examined for faults in the units, electrodes, and connecting wires. Eleven patients died as a direct result of technical failure. Histologi-cal findings in these 11 showed that 7 had a relatively healthy myocardium and should have had a good prognosis with satisfactory pacing. A few endocardial electrode wires suitable for long-term use are described, which have proved to be free from fractures with 9 months'' use in 51 patients. The incidence of disease of the myocardium in addition to disease of the main bundle or branches was 46%; the incidence of myocardial disease in those patients with ventricular fibrillation despite satisfactory pacing was 75%. Ventricular fibrillation occurred in 8 patients whose pacing systems were functioning properly. Three patients died during resuscitation effort with pacemakers during acute Adams-Stokes attacks. The need for early diagnosis and treatment of chronic heart block is emphasized.