2398Efficacy of remote controlled catheter ablation for atrial arrhythmias in patients with atrial switch

Since arterial switch procedure replaced the Mustard and Senning (M/S) operations for D-transposition of great arteries (TGA) in 1980s, there are many M/S survivors who are now over 30 yrs old. Atrial arrhythmias are common in these patients and catheter ablation is a valid alternative to medical treatment. Assess the efficacy of atrial arrhythmia ablation using remote magnetic navigation (RMN) in M/S patients. All ablations performed on patients with M/S by a single operator in a tertiary center over a 10 year period (2008–2019) were reviewed and analyzed. All documented sustained recurrences were recorded. Twenty-eight patients (57% M, age 41 [33–44] yrs, 2 Senning), underwent 41 procedures, 40 of which consisted of ablation for atrial tachycardia (AT, 36, 91%: 81% in PVA, 8% SVA, 11% in PVA+SVA), atrio-ventricular nodal re-entry tachycardia (1, 1%) or atrial fibrillation (AF 3, 8%). All procedures were carried out using remote navigation, electroanatomical mapping and 3D image integration. Pre-procedure echo showed at least moderately impaired systemic ventricle in 68% and moderate or severe tricuspid regurgitation in 58% of patients. Access to pulmonary venous atrium (PVA) was gained retrogradely in all cases while to access systemic venous atrium (SVA) either via femoral, subclavian or jugular veins. All except one procedure (98%) were acutely successful. At 1 and 3 years, 82% and 74% of patients were free from recurrent arrhythmia. Multiple procedures were required to control arrhythmias in 10 (36%) patients ablated for AT (60% in PVA, 30% in PVA+SVA). After the 2nd ablation 60% of these patients were in sinus rhythm at 3 years. On multivariate Cox analysis, Senning repair was associated with a higher recurrence risk after ablation compared to patients undergone a Mustard procedure (HR 1.47, p=0.01). Overall median procedural duration was 210 [155–265] min with a median fluoroscopy time of 0.9 [0.4–1.5] min and fluoroscopy exposure of 60 [43–120] μGy·m2. Remote magnetic navigation represents a valid treatment for atrial arrhythmias in patients post M/S operation, with good short and longer-term results. Moreover, it allows the retrograde approach sparing the transbaffle puncture and enables a low fluoroscopy exposure.