CTI Block in Persistent AF Table 1. Baseline Characteristics Hybrid group (n=32) Age (yrs) 55.4±12 Gender (male/female) 27/5 AF duration (months) 64.7±54.0 BMI (kg/m2) 25.2±3.5 Hypertension 10 (31.3%) Diabetes 9 (28.1%) Valvular heart disease 3 (9.4%) Stroke 3 (9.4%) LV EF 49.8±6.6 LA diameter (AP) 45.2±6.2 LA diameter >44 mm 17 (53.1%) AAD Class Ic 27 (84.4%) 24 (72.7%) (flecainide/propafenone) 24/3 20/4 Class III 5 (15.6%) 9 (27.3%) (amiodarone/sotalol) 3/2 6/3 ACEI/ARB 3 (9.4%) 5 (15.2%) 0.479 Beta blocker 11 (34.4%) 12 (36.4%) 0.867 Statin 5 (15.6%) 2 (6.1%) 0.214 BMI, Body mass index; LV EF, left ventricular ejection fraction; AP, anteroposterior diameter; AAD, antiarrhythmic drug; ACEI, angioten- sin converting enzyme inhibitor; ARB, angiotensin receptor blocker; AF, atrial fibrillation; LA, left atrium. Electrical cardioversion group (n=33) 52.7±12 29/4 42.0±38.2 25.7±3.7 7 (21.2%) 3 (9.1%) 4 (12.1%) 2 (6.1%) 52.4±7.1 44.2±7.9 16 (48.5%) p value 0.227 0.683 0.082 0.731 0.357 0.018 0.721 0.616 0.602 0.578 0.708 0.253 non-inducibility of atrial flutter, which was the end point of the catheter ablation. The procedure time, flouro time and RF time were: 87.3±42.6 min, 32.8±12.6 min, and 1,034.7±698.2 sec, respectively. All patients in the EC group achieved a sinus rhythm after cardioversion without complication. Clinical follow-up The mean follow-up was 67+/-33 months and 101+/-38 months in the hybrid group and EC group, respectively. During the follow-up period, recurrent atrial fibrillation or atrial tachycardia/flutter were developed in all patients. In the hybrid group, typical atrial flutter recurred in 2 patients, and atrial tachycardia or atypical atrial flutter developed in 13 patients. Seventeen patients experienced atrial fibrilla- tion. In the EC group, atrial fibrillation recurred in the greater part of patients, and atrial tachycardia or atypical atrial flut- ter developed in 4 patients. Typical atrial flutter developed in three patients. By Kaplan-Meier estimates, the 12 month AF free-survival was better in the hybrid group (12 months event-free survival 49.0% for the hybrid group patients and 33.1% for the EC group patients, p=0.048) (Fig. 1). How- ever, during a mean of 55.7+/-43.0 months of follow up, this better survival rate regressed (5 year event-free survival 24.0% for the hybrid group patients and 16.5% for EC group patients, p=0.28) (Fig. 2). On the multivariate analysis, the Table 2. Multivariate Analysis of Longterm Outcome Variables Risk ratio p value Age 1.02 0.068 Sex 0.84 0.284 Hypertension 0.98 0.791 Diabetes 0.85 0.435 Stroke 1.06 0.732 Treatment group* 1.03 0.937 Enlarged LA† 1.53 0.027 *Hybrid group and electrical cardioversion group. †Anteroposterior diameter >44 mm. type of procedure (Hybrid or EC) was not a statistically sig- nificant indicator of the long-term outcome. The preproce- dural LA size was the only independent risk factor for the recurrence of atrial arrhythmia after adjusting for age, gen- der, diabetes, hypertension, stroke and ejection fraction (odd ratio 2.5, CI of 95% 1.494-3.66, p=0.02) (Table 2). DISCUSSION In comparison with paroxysmal AF, persistent AF has a dif- ferent underlying pathophysiological mechanism.10,11 There are definite triggers and drivers of paroxysmal AF that can- not maintain long term fibrillatory activity. Paroxysmal AF is frequently triggered by ectopic beats from the muscular Yonsei Med J http://www.eymj.org Volume 53 Number 1 January 2012 79