Basketball Player with Continuous Palpitations

ANSWER
The ECG demonstrates atrial fibrillation with a rapid ventricular response with aberrantly conducted complexes, left-axis deviation, and marked T-wave abnormality. Atrial fibrillation in the setting of WPW with antegrade conduction down the accessory pathway can be life threatening. Unlike the AV node, which can decrementally slow rapid conduction to the ventricle, the accessory pathway can conduct atrial fibrillation impulses into the ventricle in a 1:1 ratio; if uncontrolled, this can result in ventricular tachycardia and/or ventricular fibrillation.

The patient was started on a procainamide drip and converted to normal sinus rhythm. He underwent an electrophysiology study, which demonstrated a single accessory pathway capable of conducting at rates of 250 beats/min located in the lateral wall of the left atrium. It was successfully ablated, resulting in normalization of his ECG.