Assessment of intraoperative radiofrequency pulmonary veins isolation for treatment of chronic atrial fibrillation in patient's undergoing rheumatic mitral valve replacement

Abstract Background Chronic atrial fibrillation (AF) is the most frequent arrhythmia in patients undergoing mitral valve surgery. Aim To evaluate the radiofrequency catheter ablation for treating chronic atrial fibrillation in patients undergoing mitral valve replacement in restoring and maintaining sinus rhythm in rheumatic mitral valve disease. Methods 24 patients with rheumatic mitral valve disease and chronic AF undergoing mitral valve surgery were assigned to intraoperative circumferential PVI pulmonary veins isolation. The preoperative characteristics (AF duration, left atrial diameter, left atrial volume, left ventricular functions, and NYHA functional class), operative data (technique, cross-clamping time, and bypass time), one-week postoperative and 3-month follow-up data as regards (heart rhythm, left atrial diameter, left atrial volume, left ventricular functions and NYHA class). Histopathological analyses of left atrial biopsies from the atriotomy site were analyzed. Results Sinus rhythm was achieved in 10 patients =41.66% and continued during the 3 months follow-up period, AF duration was significantly shorter in sinus group (3.5±1.9 years vs 6.2±4.1 years, P value = 0.004) and LA volume was significantly lower in sinus group (102.8±34.1 ml vs 237.8±124ml,P value = 0.003) preoperatively, but there was no statistically significant difference as regard the LA A-P dimensions, age ,gender, NYHA functional class, Left ventricular EF%, EPASP, Cardiopulmonary bypass time , Aortic cross-clamping time, RF ablation time, ICU and hospital stay. During 3 month post-operative follow; LA volume was significantly decreased in the sinus group (from102.8±34.1 ml to 78±21.6 ml P value=0.01) and LA dimensions significantly decreased in the sinus group (from 5.4 ±0.4cm to 4.8 ±0.3cm, P value=0.01) , with marked improvement in NYHA functional class in both groups but without significant changes in LV EF% both groups. Regarding LA biopsy, there was a significant increase in viable tissues and collagenized fibroblasts in the sinus group than the AF group. Conclusion Pulmonary veins isolation using radiofrequency ablation is safe, simple, and effective in restoring sinus rhythm in selected patients with LA Volume less than 100ml, LA transverse dimensions less than 5.0cm, short AF duration, and less degree of atrial fibrosis, and these parameters are the main predictors of recurrence after ablation.