Intrauterine and postnatal atrial fibrillation in the Wolff-Parkinson-White syndrome.

A fetal tachyarrhythmia was discovered at the thirty-second week of gestation of a 22-year old woman. Fetal echocardiography revealed atrial fibrillation with rapid ventricular rate, without any other demonstrable cardiac abnormality. In spite of therapeutic maternal blood levels of digoxin, the fetal ventricular rate and cardiac size increased, which prompted us to perform cesarean section at the thirty-fourth week of gestation. A baby with a Wolff-Parkinson-White syndrome but no other cardiac anomaly was delivered. Recurrent episodes of nonsustained atrial fibrillation with conduction over the accessory pathway occurred in the first hours of life. The Wolff-Parkinson-White pattern was not present on subsequent ECG recordings. The use of echocardiography in the diagnosis and management of this rare fetal tachyarrhythmia is emphasized.