Influence of mitral isthmus anatomy on effect of radiofrequency catheter ablation in patients with persistent atrial fibrillation

doi:10.3760/cma.j.issn.1673-4777.2016.03.001

Abstract：Objective To explore the influence of mitral isthmus (MI) anatomy on the effect of radiofrequency catheter ablation (RFCA) in patients with persistent atrial fibrillation (AF).Methods Totally 96 patients with persistent AF who underwent RFCA from June 2011 to January 2012 were enrolled.All the patients underwent echocardiography and cardiac computed tomography (CT) before RFCA.It was defined as " interposed LCX" when the left circumflex artery (LCX) passes through between the MI and the coronary sinus,thus,the patients were divided into interposed LCX group and non-interposed LCX group (48 cases in each group).RFCA was performed guided by three-dimensional electrochemical profile mapping system.The patients were followed up for 2 years and the recurrence of AF was assessed by electrocardiogram (ECG) and 24-hour ambulatory ECG 3,6,12,18 and 24 months after operation.According to the follow-up results,the patients were divided into non-recurrence group and recurrence group,and the influence factors of recurrence were analyzed.Results After 2 years follow-up,the block rate of MI and rate of sinus rhythm in interposed LCX group were significantly lower than those in non-interposed LCX group [70.8％ (34/48) vs 93.8％ (45/48),41.7％ (20/48) vs 60.4％ (29/48)] (P ＜0.05).There were 49 cases in recurrence group and 47 cases in non-recurrence group.The proportion of interposed LCX was significantly higher,the left atrial volume and MI depth were significantly greater in recurrence group than those in non-recurrence group [76.6％ (36/47) vs 24.5％ (12/49),(136 ± 18) mm3 vs (126 ± 20) mm3,(7.6 ± 1.7) mm vs (6.8 ± 2.0) mm] (P ＜ 0.05).Multivariable Cox analysis showed that interposed LCX (odds ratio =1.43,95％ confidence interval:1.22-1.91,P=0.001) and left atrial volume (odds ratio =2.76,95％ confidence interval:2.72-2.80,P =0.037) were independent risk factors of AF recurrence.Conclusion Interposed LCX and left atrial volume are independent risk factors of AF recurrence after RFCA.