EFFECTIVENESS OF ABLATION OF NEWLY DIAGNOSED PAROXYSMAL ATRIAL FIBRILLATION DURING AORTO-CORONARY BYPASS GRAFTING SURGERY

To compare effectiveness of management of subjects with newly diagnosed atrial fibrillation (AF) after aorto-coronary bypass grafting surgery (ACBG) alone and in combination with epicardial pulmonary vein isolation (PVI), 35 patients aged 62±5 years (28 men) were examined and surgically treated. The patients were randomized into two following groups: ACBG alone (Group I, n=17) and ACBG accompanied by epicardial PVI (Group II, n=18). Freedom from AF (AF burden <0.5% according to the loop recorder data) within 18 month study period was the primary endpoint. Secondary endpoints were as follows: AF burden according to the loop recorder data within the study, occurrence of thromboembolic and post-operative complications. In the course of the surgery, bipolar ablation clamp was put on the right pulmonary veins and their circular ablation was carried out. On the left side, ablation was performed using a similar technique on an “inverted” heart. All ablations were performed on the left atrial myocardium. No additional ablative lines or the left auricle resection were performed. Intra-operational assessment of the entrance block and exit block was carried out in all study subjects. Then, the ABCG surgery was carried out according to the commonly accepted technique. As the final step of surgery, Reveal XT device (Medtronic, Inc.) was implanted. All patients were free from antiarrhythmic therapy before and after the surgery within the entire study period; however all patients took β blockers. Besides, all patients received anticoagulant therapy for no less than 6 months. Within the 18 month follow-up period, total freedom from paroxysms of atrial fibrillation/flutter/tachycardia (i.e., AF burden <0.5% according to the loop recorded data; log-rank criterion, p=0.007) was detected in 16 patients (88.9%) of 18 ones of Group II and 8 patients (47.1%) of 17 ones of Group I. None of the above patients took antiarrhythmics. No significant correlation was found between the pre-operative subject data and AF recurrence. At the end of follow-up period, the AF burden according to the loop recorder data was 7.8±5.1^ΰ/ο and 1.6±1.8^ΰ/ο in Group I and Group II, respectively (p<0.001). Two patients of 11 (18.2% of both groups) with AF recurrence had asymptomatic AF. During the follow-up period, no thromboembolic events in the study subjects were documented. Thus, in patients with newly diagnosed AF and indications for direct myocardial revascularization, ACBG in combination with epicardial PVI can prevent recurrence of AF.

coronary artery disease, atrial fibrillation, aorto-coronary bypass grafting, epicardial pulmonary vein isolation, loop recorders

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