Right atrial rhabdomyoma acting as the substrate for Wolff-Parkinson-White syndrome in a 3-month-old infant.

We report a 3-month-old infant girl who presented with supraventricular tachycardia, who was detected to have a large right atrial rhabdomyoma and evidence of Wolff-Parkinson-White (WPW) syndrome with an accessory pathway corresponding to the position of the tumour. In view of the resistant cardiac arrhythmia and large size of the tumour, the infant underwent surgical excision of the tumour. The evidence of WPW syndrome disappeared from the surface electrocardiogram immediately upon removal of the tumour. A second resolving tumour in the interventricular septum was also detected during the investigation. Although there are no other stigmata of tuberous sclerosis at present, our infant requires close follow-up. Right atrial rhabdomyomas are rare and to our knowledge this is the first reported instance where we could document clearly that the tumour itself formed the substrate for the WPW syndrome.