Complete atrioventricular dissociation and His bundle tachycardia in a newborn: problems in prenatal diagnosis and postnatal management.

A newborn infant with complete atrioventricular dissociation and infranodal tachycardia, detected at 33 weeks gestation by fetal echocardiography, is described. In the perinatal period, infra or juxta-nodal tachycardia was noted, compromising the hemodynamic state of the newborn. A combination of flecainide and propranolol terminated the arrhythmia.