Impact of atrial arrhythmia on survival in adults with tetralogy of Fallot

Background: Atrial arrhythmia is a late complication after tetralogy of Fallot (TOF) repair, but arrhythmia outcomes data are limited. Objectives: The purpose of the study was to describe atrial arrhythmia presentations, outcomes of antiarrhythmic therapy, and impact of arrhythmia on transplant-free survival. Methods: We reviewed the MACHD (Mayo Adult Congenital Heart Disease) Registry and identified 113 patients (age 49 ± 13 years) with documented arrhythmia, and 302 patients without history of arrhythmia, 1990-2017. We classified arrhythmias into atrial fibrillation and atrial flutter/tachycardia based on the rhythm on the first abnormal electrocardiogram. Results: At the time of first documented arrhythmia, 58(51%) had atrial fibrillation while 55(49%) had atrial flutter/tachycardia. Of the 113 patients, 14(12%) received rhythm control with class I/III antiarrhythmic drugs (AAD), 79(70%) had direct current cardioversion, 9(8%) received rate control with class II/IV AAD, and 11(10%) received only anticoagulation. Successful cardioversion occurred in 100(89%) patients, and arrhythmia recurrence rate was 16 per 100 patient-years. The multivariate risk factors for death and/or heart transplant were atrial fibrillation (HR 1.94, CI 1.10-3.15, P = .031) and older age (HR 1.63, CI 1.12-2.43, P = .019) per 5 year increment. Conclusions: Atrial fibrillation, but not atrial flutter, was associated with reduced survival in our repaired TOF cohort. Further studies are required to determine if more aggressive antiarrhythmic therapy will improve survival in patients with atrial fibrillation.