Rosh Internal Medicine Boost Practice Exam

What is a key feature of Wolff-Parkinson-White syndrome (WPW)?

1. Short PR interval

2. Wide QRS complex

3. Delta wave

4. All of the above

The correct answer is: All of the above

Wolff-Parkinson-White syndrome (WPW) is characterized by several distinct electrocardiographic features that indicate the presence of an accessory pathway connecting the atria and ventricles, which can lead to episodes of tachycardia. A key feature of WPW is the short PR interval, which occurs due to the presence of the accessory pathway that allows electrical impulses to bypass the normal conduction delay at the atrioventricular (AV) node. Additionally, the presence of a wide QRS complex is common in WPW. This occurs because the impulse travels through the ventricles via both the normal conduction system and the accessory pathway, which leads to a delayed and wide ventricular activation pattern. Another hallmark feature is the delta wave, which appears as a slurred upstroke in the initial part of the QRS complex. This wave results from the early activation of the ventricles due to the bypass of the normal conduction pathway, further contributing to the abnormal QRS morphology. The combination of a short PR interval, wide QRS complex, and delta wave constitutes the classic ECG findings of WPW. Therefore, all these features are key indicators of the syndrome, validating the answer that includes all of them as being essential to diagnosing WP