[JNUS]

ANSWER

Wolff-Parkinson-White (WPW) syndrome:

WPW syndrome is one of the classic preexcitation syndromes that result from an accessory pathway, such as the Kent bundle, between the atria and the ventricles. Impulses traveling down this pathway bypass all or part of the intrinsic conduction system, resulting in the early depolarization of a portion of the ventricles; this preexcitation produces the classic ECG finding called the delta wave (ie, a slurred upstroke to the QRS complex). This makes the QRS appear wider than expected, and the PR interval appears somewhat shortened. The classic ECG appearance of WPW syndrome is depicted in Figure 2