What is a classic feature of Wolff-Parkinson-White syndrome on an EKG?

In Wolff-Parkinson-White (WPW) syndrome, the hallmark feature observed on an EKG is the presence of a delta wave preceding the QRS complex. This delta wave results from the pre-excitation of the ventricles due to an accessory pathway that bypasses the typical conduction through the atrioventricular (AV) node. In WPW, the electrical signals travel faster than normal because they circumvent the usual delay at the AV node, leading to this distinct appearance on the EKG.

The delta wave manifests as a slurring of the initial upstroke of the QRS complex. This is a key diagnostic feature that helps differentiate WPW from other types of arrhythmias. The presence of the delta wave is significant, as it indicates that there is an additional conduction pathway involved, which can contribute to episodes of tachycardia associated with WPW.

Other features noted in the answer choices do not represent classic findings for WPW. For example, a prolonged QT interval is typically associated with different conditions and does not specifically indicate pre-excitation. Inverted P waves can occur in other conditions, such as ectopic atrial rhythms or atrial flutter, but are not characteristic of WPW. A wide QRS complex