A 26-year-old competitive footballer has two episodes of exertional syncope. ECG shows inverted T waves in V1 to V3 and epsilon waves in the right precordial leads. Holter monitoring documents sustained monomorphic ventricular tachycardia with a left bundle branch block pattern and inferior axis. Which underlying abnormality best explains this presentation?

• A Lamin A/C mutation causing progressive atrioventricular block
• B Sarcomeric gene mutation causing asymmetric septal hypertrophy
• C Dystrophin gene deletion causing fatty infiltration of the left ventricle
• D Mutation of a desmosomal protein causing fibrofatty replacement of the right ventricular myocardium ✓

Explanation

This is arrhythmogenic right ventricular cardiomyopathy, caused by mutations in desmosomal proteins such as plakoglobin, desmoplakin, and plakophilin-2. Fibrofatty replacement of right ventricular myocardium creates the substrate for ventricular tachycardia of LBBB morphology (arising from the RV) and the epsilon wave. The LBBB-inferior axis pattern localises the circuit to the right ventricular outflow tract. Sarcomeric mutations cause hypertrophic cardiomyopathy, and dystrophin defects affect the left ventricle in Duchenne dystrophy.

Reference: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 12th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.