Catheter Ablation of Atrial Fibrillation in Transposition of the Great Arteries Treated With Mustard Atrial Baffle

Abstract

The survival of patients with D-transposition of the great arteries (D-TGA) has dramatically improved with corrective surgical procedures, including the atrial and arterial switch operations. In the current era, the majority of the adult patients typically have undergone atrial switch operations, either a Senning or a Mustard procedure. Late complications include baffle obstruction, systemic ventricular failure, systemic atrioventricular valve regurgitation, and rhythm disturbances. The most common atrial arrhythmia in this population is intra-atrial reentrant tachycardia (IART), which has been associated with development of heart failure and death.1–4 Proarrhythmic factors include atrial enlargement from tricuspid regurgitation and systemic right ventricular failure, as well as suture lines. As this population ages, chronic hemodynamic stress may result in atrial fibrillation as well. We present the first report of catheter ablation for treatment of atrial fibrillation in a patient with D-TGA treated with prior Mustard repair. ### Case Report A 41-year-old man with D-TGA status post Mustard repair presented with longstanding, recurrent atrial arrhythmias. He originally underwent balloon atrial septostomy 2 days after birth and a subsequent atrial switch procedure using the Mustard technique at 2 years of age.5 He did well until age 32, at which time he had recurrent symptomatic IART. EP study was performed. Cavotricuspid isthmus (CTI)-dependent flutter was induced and confirmed by entrainment mapping. Lines of ablation were drawn across the systemic venous baffle portion of the “medial” CTI and the pulmonary venous “lateral” CTI using a retrograde, aortic approach. Flutter terminated with ablation and could not be reinduced. Bidirectional block was demonstrated across the CTI. He remained arrhythmia-free for 2 years, then presented again at age 34 with exertional intolerance and fatigue due to partial obstruction of the pulmonary venous baffle. He underwent patch augmentation of the stenotic …