Hide and Seek: Intermittent Preexcitation Wolff-Parkinson-White Syndrome Case Report and Management Overview.

Wolff-Parkinson-White (WPW) syndrome is an uncommon form of cardiac preexcitation due to an underlying structural accessory pathway, which may lead to potentially lethal arrhythmias. Classic electrocardiogram (ECG) findings of WPW include short PR interval, slurred upstroke of the QRS complex, and prolonged QRS duration. However, in intermittent preexcitation, a rare variant in contrast to continuous preexcitation, these findings are not always present, thus masking a diagnosis of WPW syndrome. Consequently, this may adversely affect or delay the appropriate treatment of short-term tachyarrhythmias and long-term definitive therapies for this syndrome. The emergency physician should promptly obtain an ECG after the termination of any tachyarrhythmia, and maintain a high index of suspicion for intermittent preexcitation with typical WPW ECG findings which were not present on prior studies. The authors present a case of a 17-year-old female diagnosed with an intermittent preexcitation variant of WPW syndrome after a case of successfully treated symptomatic supraventricular tachycardia (SVT).