Association of Regression from Sustained to Paroxysmal Atrial Fibrillation with Clinical Outcomes: The Fushimi AF Registry.

Some patients with atrial fibrillation (AF), albeit less frequently, may regress from sustained to paroxysmal type. We sought to investigate how the regression of AF is associated with outcomes. Among the AF patients enrolled in the Fushimi AF Registry who were identified as having sustained AF at baseline, conversion of sustained to paroxysmal AF during follow-up was defined as AF regression. Major adverse cardiovascular events (MACE) were defined as a composite of cardiac death, myocardial infarction, ischemic stroke, systemic embolism, or hospitalization due to heart failure. Among 2,261 patients with sustained AF at baseline, AF regression was observed in 214 (9.5%) patients over a median follow-up period of 5.8 years (1.78% per patient-year). The annual incidence of MACE in patients with AF regression was significantly lower than those without (3.47% vs. 6.59% per patient-year, P < 0.001; adjusted hazard ratio [HR], 0.53, 95% confidence interval [CI], 0.38-0.72). Furthermore, AF regression was significantly associated with reduced risk of MACE during and after the regression period from sustained to paroxysmal forms (during regression period: adjusted HR, 0.45; 95% CI, 0.22-0.90; after regression period: adjusted HR, 0.43; 95% CI, 0.26-0.67). The incidence of MACE was comparable between spontaneous regression (35/178: 19.7%) and therapy-associated regression (either receiving catheter ablation or antiarrhythmic drugs before the regression) (7/36: 19.4%) (P=0.98). Regression of AF was associated with a lower incidence of adverse cardiovascular events. The risk of adverse events decreased significantly during the regression period and its reduction level persisted after regression. URL: http://www.umin.ac.jp/ctr/index.htm Unique identifier: UMIN000005834.