The assessment of persistent bradycardia in prenatal life.

Twelve patients with persistent fetal bradycardia were referred for echocardiographic assessment; in 10 patients the fetus had complete heart block, six isolated and four with associated structural heart disease. In the remaining two patients an atrial arrhythmia was producing a fetal sinus bradycardia. Complete heart block with structural heart disease has a poor prognosis. Isolated complete heart block has a good prognosis if the pregnancy is carefully managed. A sinus bradycardia due to atrial ectopic beats is a benign arrhythmia. Echocardiographic assessment of the heart can give an accurate prognosis in fetal bradycardia and provide a basis for appropriate obstetric management.