Which electrocardiographic finding is commonly observed in Tetralogy of Fallot?

• A. Right ventricular hypertrophy
• B. Left ventricular hypertrophy
• C. Prolonged QT without axis deviation
• D. Low voltages in limb leads

Answer: (A)

In Tetralogy of Fallot, the pulmonary outflow obstruction creates a high pressure load on the right ventricle, causing it to hypertrophy. The ECG mirrors this with signs of right ventricular hypertrophy and a rightward shift of the heart’s electrical axis. Practically, you’ll see prominent R waves in the right precordial leads (such as V1 and V2) and a pattern indicating right axis deviation, reflecting the enlarged right ventricle pushing the electrical vector toward the right.

Left ventricular hypertrophy would imply a left-sided workload issue, which isn’t the typical pattern in TOF. A prolonged QT without axis deviation or low voltages in limb leads aren’t characteristic findings for TOF’s usual ECG presentation.