Question

Young male died during exercise. History of similar history in a sibling. On gross morphology: septal thickening was seen. Most common cause of death?

• A. DCM
• B. RCM
• C. HOCM
• D. Viral Myocarditis

Hint:

Young athlete + sudden death on exertion + family history + asymmetrical septal hypertrophy = the classic sarcomeric cardiomyopathy.

Answer 1

The Correct Option is C

Step 1: Identify the clinical picture. A young male dies suddenly during exercise. There is a positive family history (a similarly affected sibling), and gross examination of the heart shows asymmetrical thickening of the interventricular septum. This triad - young patient, sudden cardiac death on exertion, autosomal dominant inheritance, and septal hypertrophy - is the classic description of Hypertrophic (Obstructive) Cardiomyopathy, HOCM.

Step 2: Why HOCM (option C) is correct. HOCM is the most common cause of sudden cardiac death in young athletes. It is an autosomal dominant disorder caused by mutations in sarcomeric proteins (most commonly \(\beta\)-myosin heavy chain and myosin-binding protein C). The hallmark gross finding is asymmetrical septal hypertrophy. During exercise the hypertrophied septum, combined with systolic anterior motion of the mitral valve, obstructs the left ventricular outflow tract; the disorganised, hypertrophied myocardium is also highly arrhythmogenic, precipitating fatal ventricular arrhythmias.

Step 3: Why the other options are wrong. DCM (Dilated Cardiomyopathy) presents with a dilated, thin-walled, globular heart and progressive heart failure, not focal septal thickening. RCM (Restrictive Cardiomyopathy) shows a stiff, non-compliant ventricle of relatively normal wall thickness with biatrial enlargement, and does not classically cause exertional sudden death in a young person with septal hypertrophy. Viral Myocarditis shows a flabby heart with patchy lymphocytic inflammatory infiltrate, not asymmetrical septal hypertrophy, and lacks the strong familial pattern.

Final answer: Option C - HOCM.