Natural history of high-grade atrioventricular block following permanent pacemaker implantation.

We followed 120 patients 4-14 yr after permanent pacemaker implantation for high-grade atrioventricular block to assess the effect of sex, age at implantation, date of implantation and various chronic co-existent illnesses on survival. The overall survival rates were 91% at 1 yr, 63% at 5 yr and 41% at 10 yr. Patients with congestive heart failure demonstrated the lowest survival rates of all cohorts studied. Survival rates of patients with congestive heart failure were significantly lower than survival rates of patients without congestive heart failure and were also significantly lower than those of patients with conduction system disease only. Similarly, patients with coronary heart disease demonstrated significantly lower survival rates than both patients without coronary heart disease and patients with conduction system disease only. The presence of hypertension, valvular heart disease, diabetes mellitus or cerebral infarction influenced survival less adversely than congestive heart failure or coronary heart disease. Survival decreased progressively with increasing age; however, the differences were not significant. Sex and date of implantation had no apparent effect on survival. Thus, coronary heart disease and the presence of congestive heart failure appear to be the major determinants of survival following permanent pacemaker implantation for high-grade atrioventricular block.