Electrophysiological findings and long-term outcomes of percutaneous ablation of atrial arrhythmias after surgical ablation for atrial fibrillation

OBJECTIVES: Percutaneous ablation (PA) for relapsing atrial tachyarrhythmias after surgical ablation is an emerging therapy. The aim of this study is to report the electrophysiological findings and the procedural long-term outcomes of reablation, in this particular clinical setting. METHODS: We retrospectively analysed all patients who were readmitted to our centre for relapsing atrial arrhythmias after surgical ablation for atrial fibrillation (AF). RESULTS: From2000 to 2011, 36 patients with previous surgical ablation of AF received additional percutaneous management. Seven patients had had biatrial Maze, 18 left atrial ablation lesion set and 11 pulmonary vein isolation. Energy sources involved were unipolar radiofrequency (RF) (n = 13), bipolar RF (n = 19), combined bipolar RF and cryoenergy (n = 2), cryoenergy (n = 1) and high intensity focused ultrasound (n = 1). The median time to reablation was 34 months (interquartile range: 10-66). The relapsing arrhythmias were left atrial tachycardia (n = 17), AF (n = 15), right atrial flutter (n = 2), right atrial tachycardia (n = 1) and biatrial atrial tachycardia (n = 1). Origin of re-entrant circuits was perimitral (n = 27), around pulmonary veins (PV) including posterior left atrium (n = 15) and cavotricuspid isthmus (n = 3). Twenty-seven (75%) patients had left isthmus catheter ablation and 11 (30%) reablation of PV. Eighteen out of the 27 perimitral circuits were in patients with previous leftatrial Maze; in 17 patients the mitral line was performed with bipolar RF only, without the addition of cryoenergy. The importance of an appropriate energy source is also underlined by the prevalence of gaps in PV isolation that occurred for two-thirds of patients treated using unipolar RF only, which has been discontinued since 2001. Ten patients (27%) needed more than 1 PA for relapsing arrhythmia. At the last follow-up of 97 ± 42 months, freedom from arrhythmias was 53% after single PAs and 67% after more than one procedure. No morbidity, mortality or strokes were recorded during the follow-up. CONCLUSIONS: Percutaneous treatment of highly symptomatic patients with unsuccessful previous surgical ablation is feasible, and relatively effective at the late follow-up. A multidisciplinary approach significantly improves the outcomes in these challenging patients.