Familial idiopathic atrial fibrillation with fetal bradyarrhythmia

A woman presented at 28 wk gestation with fetal bradycardia 50 bpm, which persisted until 42 wk when an asymptomatic male baby was delivered. Electrocardiograph at 3 wk of age documented an incessant atrial fibrillation with slow ventricular response. He continued to be asymptomatic, but on follow-up at 16 y of age, 24-h Holter monitor showed a heart rate of 23 bpm and pauses of up to 6 s when a VVIR programme endocardial pacing system was employed. ECG carried out on his asymptomatic father showed intermittent atrial fibrillation, again with a slow ventricular response. CONCLUSION: Atrial fibrillation is extremely rare in children with normal cardiac structure. Most instances of fetal bradycardia are caused by congenital complete heart block. Other rare causes such as atrial fibrillation with fetal bradycardia need to be considered. This case might be a familial disorder and looks to have a good prognosis.