Which finding is most characteristic of WPW?

Which finding is most characteristic of WPW?

• A. Delta wave
• B. Short PR interval
• C. Normal QRS duration
• D. Tall T waves

Answer: (B)

In Wolff-Parkinson-White, an accessory conduction pathway bypasses the AV node, so ventricular activation begins earlier than normal. This preexcitation shortens the time between atrial and ventricular depolarization, which shows up on the ECG as a PR interval shorter than 120 milliseconds. That reduction directly reflects the abnormal conduction circuit and is a reliable, quantifiable hallmark of WPW. While a delta wave—a slurred upstroke at the start of the QRS—often accompanies WPW and signals preexcitation, the PR interval shortening is the most universally characteristic and straightforward clue. The QRS can appear widened due to the early ventricular activation, and tall T waves are not characteristic of WPW.

In Wolff-Parkinson-White, an accessory conduction pathway bypasses the AV node, so ventricular activation begins earlier than normal. This preexcitation shortens the time between atrial and ventricular depolarization, which shows up on the ECG as a PR interval shorter than 120 milliseconds. That reduction directly reflects the abnormal conduction circuit and is a reliable, quantifiable hallmark of WPW. While a delta wave—a slurred upstroke at the start of the QRS—often accompanies WPW and signals preexcitation, the PR interval shortening is the most universally characteristic and straightforward clue. The QRS can appear widened due to the early ventricular activation, and tall T waves are not characteristic of WPW.