Outcomes of late atrial tachyarrhythmias in adults after the Fontan operation

OBJECTIVES The purpose of this study was to compare the clinical and echocardiographic features of adults who developed atrial tachyarrhythmias (ATs) late after a Fontan procedure with those who have remained free of arrhythmias. BACKGROUND Atrial tachyarrhythmias are a frequent complication of the Fontan operation. However, the outcomes in adult patients with AT who have had the Fontan operation have not been well defined. METHODS We reviewed the outcomes of 94 consecutive patients who underwent the Fontan operation between 1977 and 1994 and were followed as adults at the University of Toronto Congenital Cardiac Centre for Adults. Sixty patients had an atriopulmonary connection, 21 patients had an atrioventricular connection, and 13 patients received a lateral tunnel connection. RESULTS Thirty-nine patients (41%) had sustained AT (atrial fibrillation, atrial flutter or supraventricular tachycardia) after their Fontan procedure. Compared with patients who did not develop AT, those who did were more likely to develop heart failure (46% vs. 13%, P = 0.003) and right atrial thrombus (31% vs. 4%, P = 0.006), exhibit left atrial enlargement (mean [±SD] diameter: 44 ± 10 vs. 37 ± 9 mm, P = 0.002), exhibit right atrial enlargement (mean [±SD] volume: 139 ± 149 vs. 76 ± 54 ml, P = 0.040) and have moderate-to-severe systemic valve regurgitation (31% vs. 7%, P = 0.010). The mean survival time was not significantly different between the arrhythmia group and the arrhythmia-free group (21.2 ± 1.3 and 18.0 ± 0.7 years, respectively; P = 0.900). CONCLUSIONS Systemic atrioventricular valvular regurgitation and biatrial enlargement are commonly observed in patients who develop AT after the Fontan procedure. These patients are more likely to develop right atrial thrombus and heart failure.