Silent Circuit: Incidental Finding of Wolff-Parkinson-White Pattern in Late Pregnancy Complicated by Severe Preeclampsia.

Wolff-Parkinson-White (WPW) pattern is a rare conduction abnormality that may predispose to supraventricular tachyarrhythmias and sudden cardiac death. A 37-year-old gravida 2 para 1 woman at 35+6 weeks gestation, admitted with preterm labor and new-onset preeclampsia, developed transient chest tightness and dyspnea. Electrocardiography revealed sinus rhythm with short PR interval (the duration between the onset of atrial depolarization and the onset of ventricular depolarization), widened QRS complex (duration of ventricular depolarization), and delta wave consistent with ventricular preexcitation. Cardiac biomarkers and echocardiography were normal. She remained hemodynamically stable without sustained arrhythmia. As such, conservative telemetry monitoring was pursued. Her course progressed to severe preeclampsia requiring emergent cesarean delivery, which was uneventful. Postpartum Holter (14-day) monitoring redemonstrated delta waves with only one run of supraventricular tachycardia. She continued to remain asymptomatic at follow-up with referral for electrophysiologic evaluation. This case highlights the importance of recognizing incidental WPW during pregnancy and ensuring postpartum risk stratification for long-term management.