52 in 52: Rate vs. Rhythm for A fib


    52 in 52: Rate vs. Rhythm for A fib

    Article Citation:

    Wyse DG, Waldo AL, DiMarco JP, Domanski MJ, et al; Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Investigators. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med. 2002 Dec 5;347(23):1825-33. PMID: 12466506

    Resident Reviewer: Courtney Cassella

    What we already know about the topic

    There are two approaches to atrial fibrillation, rhythm control or rate control. The benefits of rhythm control were possibly fewer symptoms, better quality of life, better exercise tolerance, lower risk of stroke, eventual discontinuation of anticoagulation, and better survival. However, rhythm control can be difficult to achieve and often at the expense of serious adverse effects from antiarrhythmic drugs. Rate control is a simpler strategy with less toxic drugs although anticoagulation plays a more important role in this strategy.

    Why this study is important

    This study compares long-term treatment of atrial fibrillation. By comparing rhythm versus rate control the study aimed to answer if one treatment strategy was superior in regards to outcomes for mortality, ischemic stroke, or hemorrhage.

    Brief overview of the study

    A total of 4060 patients over the age of 65 years who had risk factors for stroke or death were enrolled in this study. The rhythm-control strategy group allowed the treating physician to pick antiarrhythmic drugs to maintain sinus rhythm. The rate control group used beta-blockers, calcium-channel blockers, digoxin, or a combination of drugs for a goal heart rate less than 80 bpm at rest and less than 110 bpm during a 6-min walk test. Mortality was higher in the rhythm-control group but was not statistically significant. There was no difference in the composite endpoint of death, disabling stroke, disabling anoxic encephalopathy, major bleeding, or cardiac arrest.


    Limitations in this study include patients were only eligible if age was greater than 65 years or those with risk factors for stroke making generalizability to younger patients difficult. Furthermore, given the perceived benefits of rhythm control, if patients were thought to have more frequent or severe symptoms investigators may not have enrolled them in the study. Lastly the follow-up was 5 years and given atrial fibrillation patients often need therapy for longer treatment benefit in one group or the other could be masked.

    Take home points

    • Rate control is non-inferior to rhythm control in the long term treatment of atrial fibrillation
    • Rate control may be superior to rhythm control given the adverse drug effects of rhythm control agents
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