Improved Ventricular Function after TEE-guided Cardioversion of Atrial Arrhythmias in Patients after the Fontan Operation

Objective Atrial tachyarrhythmias frequently develop after the Fontan operation. Patients with Fontan physiology rely on atrial contribution to cardiac output, and thus control of atrial arrhythmias is important. Outcomes after cardioversion in patients after Fontan have not been reported. We sought to determine if cardioversion results in improved echocardiographic parameters or clinical symptomatology; and, discern risk factors for arrhythmia recurrence. Design We retrospectively analyzed the Mayo Clinic echocardiographic database to capture patients after the Fontan operation who underwent transesophageal echocardiography–guided electrical cardioversion from 2000–2015. Clinical and echocardiographic data were collected and compared at baseline and follow‐up. Results Eight hundred ninety patients with prior Fontan operation underwent echocardiographic evaluation; 341 (38%) developed atrial arrhythmias. Thirty‐six patients [20 males, median age 29 (12–51)] underwent transesophageal echocardiography–guided cardioversion of atrial arrhythmias [atrial flutter/intraatrial reentrant tachycardia (75%); atrial fibrillation (25%)]. At follow‐up, improvements were noted in ejection fraction by 10% (P