This patient has EKG features of Wolff-Parkinson-White syndrome (WPW): widened QRS with delta wave and short PR interval. Patients may also have “pseudo-Q waves” in anterioinferior leads (which are negative delta waves).
Treatment of WPW: Asymptomatic patients with incidental diagnosis should be referred to a cardiologist. Patients with narrow-complex SVT can be treated as for any other SVT. Patients with wide-complex SVT should undergo cardioversion. Patient with atrial flutter or atrial fibrillation and WPW who are given an AV nodal blocking agent (digoxin, Ca channel blocker, adenosine) may degenerate to ventricular tachycardia or fibrillation – avoid. Patients with recurrent episodes of SVT are referred to a cardiologist electrophysiologist for ablation.
This patient did not currently have a tachydysrhythmia in the ED, but was symptomatic (syncope) and found to have an ejection fraction of 41%. She was admitted to the PICU with cardiology consulting.
A great overview of WPW from lifeinthefastlane can be found here