- MY ACCOUNT
Radiofrequency ablation (RFA) of atrial fibrillation(AF) has emerged as an important strategy in the management of paroxysmal (PAF) and symptomatic persistent atrial fibrillation (PersAF). There are limited studies on late recurrences of atrial fibrillation in patients with PAF and complex PersAF patients undergoing RFA. The previous studies fail to mention the role of clinical predictors in late recurrences of atrial fibrillation after RFA.
Wokhlu et al. have published the long term outcomes of 774 patients with AF that underwent RFA at a single institution over a 7 year period. The patients were divided into PAF (55%) and PersAF groups (45%). Patients discontinued anti arrhythmic drug (AAD) therapy 5 half lives before and amiodarone therapy 2 months prior to ablation. Pulmonary vein isolation (PVI) was used in 38% of the patients and wide circumferential ablation (WCA) was used in 62 % of the patients undergoing ablation. Clinical follow up was conducted at 3 months after the index procedure and then annually. Twenty four hour Holter monitoring was used to detect asymptomatic recurrences of AF at 3 months. Patients received questionnaires at baseline and at follow up visits. Atrial arrhythmias were counted as recurrences after a 2 month blanking period. Recurrence was defined as absence of AF control despite AAD therapy or repeat ablations. Overall mean age of the patient population was 54 year with 81 % males. Patients with PersAF were more likely to have underlying cardiovascular disease, higher left atrial (LA) size and lower left ventricular ejection fraction (LVEF). Median follow up duration was 3 years post ablation. Overall 559 patients completed 2 year follow up.
Sixty four percent of the patients in the overall cohort were free of recurrence at last follow up. Recurrences were midterm (2-6 months) in 54 %, late (7-12 months) in 17 % and very late (>12 months) in 29 % of patients. Recurrences were more common in PersAF group over the entire follow up and at 30 months. Very late recurrences increased disproportionately in the PersAF group. Univariate predictors of recurrences were diabetes, PersAF, hypertension, family history of AF and LA diameter of >45 mm where as PersAF and diabetes were the only independent predictors by multivariate analysis. LA size > 45 mm was significant predictor for recurrence by multivariate analysis among patients with PAF. PersAF, hypertension, diabetes and WACA were independent univariate predictors whereas PersAF and WACA were independent multivariate predictors of very late recurrences. There was no difference in AAD therapy between PAF and PersAF group at 2 year follow up. AF elimination rate at 2 years after last ablation was greater in PAF group (71 %) compared to PersAF group (61 %, p = 0.04). Despite repeat ablations and AAD therapy, 15 % of PAF patients and 23 % of PersAF patients experienced recurrences. There was improvement in AF elimination rate over time.
This is a large, prospective, long-term outcome study of patients with symptomatic AF that makes this study significant. There was a significantly higher incidence of late recurrences of AF in this study which calls for more intense and longer term follow up. The higher rate of late recurrence (47%) over 30 month period could be explained by higher proportion of patients with PersAF and cardiovascular disease. Higher 2 year recurrence of AF in PersAF group is not surprising considering lower re-ablation rate (15%) in this group. This study also signifies the role patient related factors such as diabetes in recurrence of AF.
There has been a significant improvement in the ablative practices in the recent years, so one should be cautious in extrapolating these recurrence rates. Also it is extremely difficult to capture all the recurrences (symptomatic as well as asymptomatic) in the real world without intensive rhythm monitoring which makes one question the actual success rate that may be lower than quoted in the study. To resolve these issues, results of CABANA are eagerly awaited.
Wokhlu A, Hodge DO, Monahan KH, Asirvatham SJ, Friedman PA, Munger TM, Cha YM, Shen WK, Brady PA, Bluhm CM, Haroldson JM, Hammill SC, Packer DL. Long-Term Outcome of Atrial Fibrillation Ablation: Impact and Predictors of Very Late Recurrence. J Cardiovasc Electrophysiol. 2010 May 24.
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