Prenatal diagnosis of junctional ectopic tachycardia.

The congenital form of junctional ectopic tachycardia has never been reported during the prenatal period. We describe a case in which the diagnosis could be ascertained in utero with the superior vena cava/ascending aorta Doppler approach. The diagnosis was based on the evidence of ventricular tachycardia with atrioventricular (AV) dissociation and the simultaneous occurrence of atrial and ventricular contractions during an episode of tachycardia with 1:1 AV relationship.