Enrique M. Velasquez, MD, D. Luke Glancy, MD, and Raja W. Dhurandhar, MD

A 69-year-old male resident of a nursing home presented to the emergency department with complaints of shortness of breath and atypical chest pain. A 12-lead electrocardiogram was done on admission (Figure 1).

The electrocardiogram was normal except for prominent R waves in the right precordial leads (V₁, V₂). The differential diagnosis of tall R waves in these leads includes right ventricular hypertrophy, ventricular septal hypertrophy, posterior myocardial infarct, right bundle branch block, ventricular preexcitation of the Wolff-Parkinson-White type, Duchenne's muscular dystrophy, dextrocardia and/or rightward displacement of the cardiac apex, and a normal variant (diagnosis of exclusion) (1).