Unusual course of congenital complete heart block in an adult: A case report.

BACKGROUND: Congenital complete heart block (CCHB) with normal cardiac structure and negativity for anti-Ro/La antibody is rare. Additionally, CCHB is much less frequently diagnosed in adults, and its natural history in adults is less well known. CASE SUMMARY: A 23-year-old woman was admitted to our hospital for frequent syncopal episodes. She had bradycardia at the age of 1 year but had never had impaired exercise capacity or a syncopal episode before admission. The possible diagnosis of acquired complete atrioventricular block was carefully ruled out, and then the diagnosis of CCHB was made. According to existing guidelines, permanent pacemaker implantation was recommended, but the patient declined. With regular follow-up for 28 years, the patient had an unusually good outcome without any invasive intervention or medicine. She had an uneventful pregnancy and led a normally active life without any symptoms of low cardiac output or syncopal recurrence. CONCLUSION: This case implies that CCHB in adulthood may have good clinical outcomes and does not always require permanent pacemaker implantation.