A 15 year old boy died suddenly while playing in the field. On autopsy, fibrofatty replacement of right ventricular myocardium is seen. Most likely diagnosis is:

Arrhythmogenic right ventricular dysplasia is an inherited hea muscle disorder characterized pathologically by fibrofatty replacement of right ventricular myocardium. It represents the leading cause of sudden death on the athletic field. Clinical manifestations include ECG depolarization and repolarization abnormalities commonly localized to right precordial leads. Cardiac imaging techniques demonstrate right ventricular global or regional morphologic and functional abnormalities. Physical exercise can acutely increase right ventricular afterload and cavity enlargement, which in turn, can trigger ventricular arrhythmias by stretching the diseased right ventricular musculature. Ref: Estes III N., Link M.S., Maron B.J. (2011). Chapter 101. The Athlete and the Cardiovascular System. In V. Fuster, R.A. Walsh, R.A. Harrington (Eds), Hurst's The Hea, 13e.