Atrial fibrillation is the most common cardiac arrhythmia, affecting about 2.3 million persons in the United States. Persons with atrial fibrillation have a four to five times greater risk of stroke and twice the risk of death. There are two approaches to management of atrial fibrillation: rate control and rhythm control. In rate control, medication is used to prevent thromboembolic events. In rhythm control, electric or pharmacologic cardioversion to sinus rhythm is followed by administration of antiarrhythmic agents to maintain this rhythm. Both strategies have risks and benefits with regard to morbidity and mortality. Recent studies have sought to determine which of these two strategies result in better clinical outcomes. De Denus and associates performed a meta-analysis of published studies to evaluate rate versus rhythm control in terms of patient outcomes.
The authors searched MEDLINE, the Cochrane Controlled Trials Registry, and the International Pharmaceutical Abstracts database to identify randomized controlled trials comparing rate and rhythm control strategies as first-line therapies. Trials were excluded if they included patients who had undergone surgery or if they evaluated invasive or surgical interventions as first-line therapy for atrial fibrillation. The authors extracted data and assessed the quality of trials based on established criteria. The data were given a quality rating according to the risk for bias: (A) low—all quality criteria were met; (B) moderate—one or more quality criteria were only partly met; or (C) high—one or more criteria were not met.
Five published trials with a total of 5,239 patients met the inclusion criteria. In the individual trials, there were no significant differences in all-cause mortality when rate control was compared with rhythm control. When the data were pooled, there still was no significant difference in all-cause mortality rates between rate-control and rhythm-control groups (13.0 and 14.6 percent, respectively; odds ratio, 0.87; 95% confidence interval, 0.74 to 1.02; P = .09). However, there was a positive trend in the rate-control group. The pooled data showed no significant difference in the rate of ischemic stroke between the rate-control and the rhythm-control groups.
The authors conclude that in patients with persistent atrial fibrillation, or with atrial fibrillation that is likely to reoccur, rate control in combination with anticoagulation seems to be comparable with attempting to maintain sinus rhythm. They add that the rhythm-control strategy may be indicated in selected patients, although it should not be the preferred strategy in all patients with atrial fibrillation.