Abstract 13198: Complete Left Atrial Surgical Ablation with Bipolar Radiofrequency Effectively Treats Atrial Fibrillation but Decreases Left Atrial Function
Introduction - Complete bipolar left atrial (LA) surgical ablation is a relatively new procedure for treatment of atrial fibrillation (AF). Although this procedure is effective, the extensive lesions may have a deleterious effect on LA dimensions and function.
Methods - 35 patients (age 66, 56% male) with paroxysmal (n=7) or persistent AF (n=28, duration 4.8 ± 7 years) scheduled for valve surgery and/or coronary bypass (CABG) were included for concomitant surgical ablation. The ablation consisted of epicardial pulmonary vein isolation (PVI), creation of an endo-epicardial LA roofline, a mitral isthmus line and a line from the left atrial appendage to the left pulmonary veins. A control group (n=35, 28 paroxysmal AF, age and gender matched) was selected from patients undergoing bipolar epicardial PVI concomitant to valve surgery and/or CABG. 24-hour Holter recordings were performed at 3, 6 and 12 months. Recurrence of AF was defined as any registration of atrial arrhythmia after 3 months blanking. LA dimensions and function were assessed on 2-dimensional echocardiography.
Results - The overall success was 69% for complete LA ablation (11 ± 3 months) and 78% for PVI (12 ± 7 months). LA volume and deformation (strain), decreased from 74 ± 21 to 51 ± 13 ml and 15 ± 6 to 10 ± 4% respectively after complete LA ablation (p>0.01). After PVI, LA volume decreased from 67 ± 22 to 58 ± 20 ml, while strain increased from 17 ± 6 to 18 ± 8% (p>0.05). Atrial contraction parameters were only available in patients with sinus rhythm before and after surgery (n=7 for complete LA ablation, n=28 for PVI). Strain rate decreased from -0.88 ± 0.35 to -0.48 ± 0.30 s-1, peak A-velocity from 88 to 55 cm/s and LA ejection fraction (LA-EF) from 41 to 31% (p>0.05). In the PVI group, LA-EF increased from 38 to 45% (p>0.05), while the other parameters remained stable.
Conclusion - LA volume, deformation and function decreased after complete LA ablation, indicating reverse remodeling combined with significant damage to the LA due to the extensive ablation. In contrast, surgical PVI decreases LA volume while increasing deformation and function, indicating LA reverse remodeling only. Therefore, complete LA surgical ablation should be restricted to patients in which PVI is suspected to be insufficient.
- © 2012 by American Heart Association, Inc.