A 19-year-old male basketball player with a history of Asperger's syndrome with high function develops gradually worsening shortness of breath on exertion while playing sports. Over the next few months, he is admitted twice for exertional chest pain, shortness of breath, and one episode of syncope. No known family history of sudden cardiac arrest was identified. His electrocardiogram (ECG) reveals normal sinus rhythm at 71, bi-atrial enlargement, and left ventricular hypertrophy with repolarization changes (Figure 1).

A transthoracic echocardiogram (Video 1 and 2) reveals that the left ventricular (LV) wall thickness was massively increased (>30 mm) in a pattern consistent with severe apical hypertrophic cardiomyopathy. There is complete systolic obliteration of the ventricular cavity but only a minimal dynamic gradient in the LV outflow tract (LVOT) (12 mm Hg) is detected. Cardiac magnetic resonance imaging (MRI) reveals severe apical hypertrophic cardiomyopathy with extensive fibrosis in the areas of myocardial thickening, particularly in the midventricular segments (maximum thickness of 35 mm). Coronary angiogram reveals normal coronaries. Right heart catheterization reveals normal hemodynamics. Genetic testing detects a deleterious mutation in the myosin heavy chain mutation (MYH7 Arg⁴⁰³Gln – a Class I mutation)

Video 1

Video 2