Which statement is true for Wolff-Parkinson-White syndrome?

Which statement is true for Wolff-Parkinson-White syndrome?

• A. Delta wave is present
• B. Short PR interval
• C. P waves vary in morphology
• D. Tall T waves

Answer: (B)

Wolff-Parkinson-White syndrome involves an accessory conduction pathway that bypasses the AV node, causing pre-excitation of the ventricles. Because part of the impulse reaches the ventricles earlier than through the normal AV nodal route, the time from the start of atrial depolarization to the start of ventricular depolarization is shortened—the PR interval is reduced. This early ventricular activation often produces a delta wave, a slurred upstroke at the beginning of the QRS, and the QRS complex may be widened as a result of the abnormal initial ventricular depolarization. Among the statements, the consistently true finding that reflects this pre-excitation is the shortened PR interval. The presence of a delta wave can occur but is not as universally observed as the PR shortening, and the other options describe patterns not characteristic of WPW.

Wolff-Parkinson-White syndrome involves an accessory conduction pathway that bypasses the AV node, causing pre-excitation of the ventricles. Because part of the impulse reaches the ventricles earlier than through the normal AV nodal route, the time from the start of atrial depolarization to the start of ventricular depolarization is shortened—the PR interval is reduced. This early ventricular activation often produces a delta wave, a slurred upstroke at the beginning of the QRS, and the QRS complex may be widened as a result of the abnormal initial ventricular depolarization. Among the statements, the consistently true finding that reflects this pre-excitation is the shortened PR interval. The presence of a delta wave can occur but is not as universally observed as the PR shortening, and the other options describe patterns not characteristic of WPW.