The natural history of asymptomatic complete heart block. A case series from the Manitoba Follow-up Study.

Long-standing asymptomatic complete heart block is unusual in adults. The natural history of this condition with advancing age is unknown. Four cases of complete heart block documented in patients for 23 to 48 years are reported. These men had no evidence of structural heart disease and functioned normally without symptoms for many years. Three of the four subsequently developed symptoms and required permanent pacemaker insertion. These cases illustrate the good prognosis of asymptomatic complete heart block, but raise the concern that with advancing age, intervention with pacing frequently is necessary.