Surgery for atrial fibrillation with radiofrequency ablation: four years experience

OBJECTIVES: Atrial fibrillation (AF) is very common in patients undergoing open heart surgery. AF ablation with different sources of energy, enables the surgeon to create linear lesions rapidly and safely. However, results of these technologies need examination. We report the clinical results obtained in a 4-year experience using mono- and bipolar radiofrequency (RF) ablation of AF in a heterogeneous group of 183 patients. METHODS: From May 2001 until December 2005 a total of 183 patients underwent pulmonary vein isolation using RF energy. In 73 cases, monopolar RF was used. Energy was applied in the endocardium in 40 cases (Group A) and in the epicardium in 33 cases (Group B). From May 2003, bipolar RF was used in a total of 110 patients (Group C). Duration of AF, left atrial dimensions, age or reoperations, were not considered contraindications to ablation. Ablation procedure for AF ablation was associated with a variety of cardiac procedures, from isolated mitral valve procedure to complex ascending aorta operations. RESULTS: In-hospital mortality was 3.8% in the whole group (range 2.7-6.1%). Mortality and morbidity were not related with the ablation procedure. At the follow-up time of 50.9+/-3.3, 48.2+/-3.1, 32.7+/-0.9 months (Group A, B and C, respectively), sinus rhythm (SR) is present in a percentage of 75%, 67.7%, 79.4% of patients. Higher incidence of AF recurrence occurred in the first six months after surgery in all three groups. Late recurrence was higher in the epicardial group and overall freedom of AF was 64% in Group A, 46% in Group B and 71.1% in Group C (P=0.01). CONCLUSIONS: Our results demonstrate that the epicardial monopolar RF ablation obtains worse results than the endocardial monopolar RF and the bipolar RF ablation. Bipolar RF theoretically grants transmurality and is easy and safe, and a complete ablation setting lines can be achieved. Bipolar RF enables extension of ablation to every patient on AF undergoing a cardiac operation.