On an EKG, Wolff-Parkinson-White syndrome is characterized by which feature?

On an EKG, Wolff-Parkinson-White syndrome is characterized by which feature?

• A. Presence of flat-line EKG
• B. Delta waves creating shortened PR intervals
• C. Regular sized QRS complexes
• D. Stable heart rate

Answer: (B)

Wolff-Parkinson-White (WPW) syndrome is characterized by the presence of delta waves on the EKG, which result in shortened PR intervals. This specific finding occurs due to the existence of an accessory conduction pathway (the Bundle of Kent) that allows electrical impulses to bypass the normal conduction route through the AV node. As a result, there is a premature activation of the ventricles, leading to the appearance of delta waves on the EKG.

The delta wave manifests as a slurring of the upstroke of the QRS complex, followed by a wide QRS. This characteristic pattern is crucial for diagnosing WPW and distinguishes it from other types of pre-excitation syndromes. The shortened PR interval is a direct result of the early depolarization of the ventricles due to this accessory pathway. Understanding this abnormal conduction is essential for interpreting EKGs and managing patients with WPW syndrome effectively.