paeds94

A 13-year-old girl is brought by her mother to the A&E with breathlessness, fatigue and palpitations. Anamnesis does not reveal any syncope or chest pain in the past. on the other hand, these symptoms were present intermittently for a year. Clinical examination reveals a pan-systolic murmur associated with giant V waves in the jugular venous pulse. Chest auscultation and resting ECG are normal. 24 hour ECG tape shows a short burst of supraventricular tachycardia. What is the most probable diagnosis?