Fetal bradyarrhythmia: diagnosis and outcome.

Seventeen patients were referred to out ultrasound unit because of fetal bradyarrhythmia (less than 100 bpm). Duration of pregnancy varied between 21 and 40 weeks. Bradyarrhythmia was diagnosed as atrioventricular block (n = 12), mild sinus bradycardia (n = 3), and irregular bradycardia (n = 2). The association with maternal collagen disease was 29 per cent and with cardiac structural defects 59 per cent. The overall mortality was 41 per cent. There were three abnormal karyotypes (17 per cent) and four cases of cardiac compromise (23 per cent). Prognosis depends on the nature of the bradyarrhythmia and recognition of associated pathology such as cardiac structural defects, abnormal karyotype and degree of cardiac compromise.