WPW

An ECG of a 59-year-old woman with known Wolff-Parkinson-White (WPW) syndrome is shown below. The delta (Δ) waves are small, but definite. This patient, like many patients with WPW syndrome, often does not have them at all times. The PR intervals are not short (ie, <120 ms), usually one of the diagnostic features of WPW. However, the Δ wave is the key feature and the PR interval here suggests a delay in the normal A-V conduction, sometimes called “sick Kent syndrome.” The WPW QRS is a fusion beat between the accessory pathway and the normal A-V pathway.