Utility of preoperative electrophysiologic studies in patients with Ebstein's anomaly undergoing the Cone procedure.

Background: Ebstein's anomaly is associated with a high incidence of atrial and ventricular arrhythmias. The Cone procedure has become an effective hemodynamic intervention for this malformation. In response to two late postoperative sudden deaths in our early institutional Cone experience, a standardized plan for aggressive rhythm evaluation was instituted, including preoperative electrophysiologic studies (EPS) and intraoperative implantable loop recorder (ILR) placement.

Objective: The purpose of this study was to measure the yield of this diagnostic protocol for patients with Ebstein's anomaly undergoing surgical repair and to describe its influence on patient management.

Methods: All patients at Boston Children's Hospital with Ebstein's anomaly who underwent the Cone procedure from December 2006 to September 2012 were reviewed. Pre- and postoperative arrhythmias and therapies were documented. For patients who underwent preoperative EPS, all arrhythmia substrates and interventions were recorded.

Results: A total of 74 patients were included, 42 of whom underwent preoperative EPS. Significant findings were documented during EPS in 29 of the 42 patients (69%), including eight patients with no prior suspicion of arrhythmias. Seventeen patients had successful catheter ablation during EPS, and EPS data guided one or more intraoperative rhythm interventions for the remainder. During follow-up, diagnostic yield from ILR was low. Since implementing a more aggressive diagnostic strategy, no further sudden deaths have occurred.

Conclusion: Preoperative EPS has a high diagnostic and therapeutic yield in patients with Ebstein's anomaly undergoing the Cone operation. It is reasonable to recommend EPS as a routine preoperative test for this population.