Sudden Cardiac Arrest in a Pregnant Woman with Wolff-Parkinson-White Syndrome with Fractionated Delta Wave Due to Middle Cardiac Vein Diverticulum.

Abstract

A 26-year-old woman at 34 weeks' gestation presented with out-of-hospital cardiac arrest due to ventricular fibrillation. Her electrocardiogram (ECG) showed sinus rhythm with a short P-R interval and an unusually fractionated delta wave. The delta wave was positive in leads I and V2-V6, isoelectric in V1, and negative in inferior leads. An electrophysiology study revealed antegrade accessory pathway conduction with the earliest ventricular activation in the posteroseptal region. Three radiofrequency (RF) ablation procedures, including attempts with pulsed field ablation, were ultimately unsuccessful. Cardiac computed tomography angiography revealed a diverticulum of the middle cardiac vein (MCV). Irrigated RF ablation within the diverticulum successfully eliminated the accessory pathway conduction. We propose that multiple fibers of the coronary sinus or the MCV muscular coat may interface via the diverticulum with the ventricle, leading to multiple wavefronts of ventricular pre-excitation, and that the resultant delta-wave fractionation may allow identification of such an epicardial accessory pathway.