Atrial arrhythmia predicts late events and mortality in patients with D-transposition of the great arteries and atrial switch repair

Aims: Patients with D-transposition of the great arteries (D-TGA) and atrial switch experience late morbidity and mortality related to atrial arrhythmias and systemic right ventricular (SRV) failure. We sought to analyze the influence of atrial arrhythmias on long-term outcomes in this group. Methods: A retrospective review of all patients with D-TGA and atrial switch followed at a tertiary care center was performed. Results: 148 patients (63.5 % male; age 30.4 +/- 10.6 years) were followed for 12 +/- 9.8 years. Death or cardiac transplantation occurred in 22(15 %) patients and heart failure hospitalization occurred in 30(20 %) patients. Atrial arrhythmias were documented in 82(55.4 %) patients. Atrial fibrillation at the first visit (Kaplan-Meier estimate, p = 0.003) and atrial fibrillation as a time-dependent variable (HR 3.50, p = 0.006) predicted increased risk of death or cardiac transplantation. A triad of atrial fibrillation, prolonged QRS duration/RBBB, and severe SRV dysfunction (SRV EF < 35 %) emerged as a unique signature of a higher-risk population. Atrial tachycardia and flutter, while not associated with mortality, increased the risk of heart failure hospitalization (HR 3.5, p = 0.001). Moreover, 2/6 cases of resuscitated sudden cardiac arrest were caused by atrial flutter, and more patients received inappropriate shocks for atrial arrhythmias(16 %) than appropriate shocks (2.3 %). Conclusion: In D-TGA patients with atrial switch, there is a complex interplay between atrial arrhythmias and the SRV. Key ECG parameters, arrhythmia events and sequelae create a unique patient-specific fingerprint strongly associated with future events and mortality. This higher-risk cohort will need further characterization to delineate who may benefit from preemptive arrhythmia intervention.