Sudden death in a child with an unusual accessory connection

An 8-year-old boy with Wolff-Parkinson-White syndrome died suddenly whilst exercising. He had been well with no immediate preceding symptoms of an arrhythmia, and was receiving no drugs. As an infant he had suffered recurrent episodes of atrioventricular reciprocating tachycardia (AVRT) and had documented pre-excited atrial fibrillation. At electrophysiological (EP) study, the refractory periods of his two accessory pathways were less than 220 ms. Drugs were discontinued at 4 years of age when he remained asymptomatic. Autopsy confirmed a very unusual accessory pathway. It was a muscular connection between the base of the right atrial appendage and the right ventricle, distant from the annulus of the tricuspid valve.