-Hypertrophic cardiomyopathy is the most common cause of sudden cardiac death in young athletes. It is an autosomal dominant condition with variable expression. It accounts for 1/3 of cases.
–Coronary artery abnormalities are second in frequency as a cause of sudden cardiac death in this population, with idiopathic ventricular hypertrophy third.
Reference
J Am Coll Cardiol 2013;61(10):1027-1040. http://www.sciencedirect.com/science/article/pii/S073510971205735X