Patients with recently diagnosed atrial fibrillation (AF) had a lower risk of adverse outcomes with rhythm control versus rate control treatment in a large observational study in Korea. "The findings surely did surprise us," Dr. Boyoung Joung of Yonsei University College of Medicine in Seoul told Reuters Health by email. "The negative results regarding the effects of AF rhythm control on cardiovascular outcomes from the AFFIRM and other trials have made it difficult for physicians and patients to find any benefit of rhythm control other than symptom relief." "The results of the EAST-AFNET4 and this study suggest treatment timing is the key to success," he said. "Furthermore, the effect of early treatment on better outcomes might support initiatives to implement screening for AF among asymptomatic individuals in clinical practice." However, he noted, "according to current guidelines, rate control still can be a preferred option in asymptomatic patients with AF, older patients with more comorbidities, those with an increased left atrium, and those without evidence of tachycardia-induced cardiomyopathy or heart failure with reduced ejection fraction." As reported in The BMJ, Dr. Joung and colleagues analyzed data from the Korean National Health Insurance Service database on 22,635 adults with AF and cardiovascular conditions (e.g., previous stroke or myocardial infarction, heart failure, hypertension), newly treated with rhythm control (antiarrhythmic drugs or ablation) or rate control between 2011-2015. Fifty-four percent were men; the median age was 70; and the median follow-up was 2.1 years. The primary outcome was a composite outcome of death from cardiovascular causes, ischemic stroke, hospital admission for heart failure, or acute myocardial infarction. Among patients with early AF treatment - i.e., initiated within one year of diagnosis - rhythm control was associated with a lower risk of the primary composite outcome, with a weighted incidence rate per 100 person years of 7.42 with rhythm control versus 9.25 with rate control (hazard ratio, 0.81). By contrast, in patients with late AF treatment - i.e., initiated after one year from diagnosis - no between-group difference was found between rhythm and rate control: weighted incidence rate per 100 person years was 8.67 with rhythm control versus 8.99 with rate control (HR, 0.97). Further, no significant between-group differences in safety outcomes were found across different treatment timings. The authors conclude, "Earlier initiation of treatment was linearly associated with more favorable cardiovascular outcomes for rhythm control compared with rate control." Dr. Nikhil Warrier, medical director of electrophysiology at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, California, commented on the study in an email to Reuters Health. Like Dr. Joung, he noted that the findings "are certainly in line with the EAST AFNET4 data in a sicker patient population." "Clinically," he said, "we definitively see increased effectiveness of rhythm control strategies when implemented early whether that is antiarrhythmic therapy or catheter ablation." That said, he noted that the observational nature of the study "makes it prone to bias and confounding." "We cannot use these results to demonstrate causality," he said. "Interestingly, there was a low incidence of ablation therapy in both groups, despite its availability." "Elderly patients, specifically those that are frail and have rate-controlled AF with absence of symptoms, represent a reasonable patient population for continued rate control therapy," he said. "Patients that have issues with systemic anticoagulation are likely not candidates for rhythm control, as well (specifically, catheter ablation)." Dr. Warrier suggests that clinicians refer patients to a heart rhythm specialist to determine which treatment would be most beneficial for them. —Marilynn Larkin Source
