ECG Review

ECG from a 22-year-old Man in a Wheelchair

By Ken Grauer, MD, Professor Emeritus in Family Medicine, College of Medicine, University of Florida. Dr. Grauer is the sole proprietor of KG-EKG Press, and publisher of an ECG pocket brain book.

Scenario: The ECG shown above was obtained from a 22-year-old man in a wheelchair. How would you interpret the tracing? Can you think of a condition that might account for this clinical scenario?

Interpretation: The ECG shows sinus rhythm at about 70/minute. The PR interval is normal, but the QRS is prolonged to at least 0.12 second. QRS morphology in the three key leads (I, V1, V6) is not consistent with either left or right bundle branch block. Therefore, we would classify the conduction defect as nonspecific interventricular conduction delay (IVCD).

Continuing with the interpretation, we note marked left axis deviation consistent with left anterior hemiblock. QRS amplitude is markedly increased in lead aVL, although reliability of the ECG diagnosis of left ventricular hypertrophy (LVH) is reduced in the presence of conduction defects.

Regarding QRST changes, there are deep and wide Q waves in the high lateral leads (I, aVL). In addition, there is a small Q wave in lead V2. QRS morphology in lead V1 is peculiar, as there is an rSr's' complex. This is followed by abrupt transition by lead V2 in which a disproportionately tall R wave is noted. R wave amplitude drops off by lead V3, with persistent S waves seen throughout the remaining precordial leads. There is ST segment depression in lateral leads I and aVL, which may reflect "strain" from suspected LVH. That said, ST-T wave changes do not appear to be acute.

Our overall impression is that this ECG is clearly abnormal and highly unusual for a young adult. Given the history of a "22-year-old man in a wheelchair" should suggest the possibility of a cardiomyopathy such as Duchenne Muscular Dystrophy (DMD). There are more than 20 different genetic forms of muscular dystrophy, of which DMD is the most common of these rare disorders. DMD is almost exclusively seen in males, with unfortunate outcome of progressive muscle deterioration and weakness that invariably leads to death at an early age. Cardiac involvement is the rule, with the most common ECG abnormalities in DMD and other muscular dystrophies being QRS widening from conduction defects (usually nonspecific IVCD); abnormal Q waves not due to infarction (especially in lateral leads); and a polyphasic rSr's' in lead V1 with surprisingly tall anterior precordial R waves. All of these features are seen in this case.

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