What are the ECG findings in Wolff-Parkinson-White pattern?

• A. Prolonged QT interval
• B. Tall T waves
• C. Short PR interval, delta wave, and widened QRS
• D. Normal ECG

Answer: (C)

Wolff-Parkinson-White pattern reflects preexcitation of the ventricles due to an accessory pathway that bypasses part of the normal AV conduction system. The hallmark on ECG is a short PR interval because the impulse reaches the ventricles earlier than usual. This preexcitation also produces a delta wave, a slurred upstroke at the start of the QRS, and the overall QRS complex appears widened because ventricular activation is split between the normal pathway and the accessory pathway, altering the initial ventricular depolarization. Together, these findings—short PR interval, delta wave, and widened QRS—fit WPW best. Prolonged QT, tall T waves, or a normal ECG do not describe this preexcitation pattern.