Slow it or Fix it? Long-term Management Strategy for Atrial Fibrillation

This is part of a recurring series examining landmark articles in Emergency Medicine, in the style of ALiEM’s 52 Articles.

Main Points:

  1. This 2002 randomized multicenter trial found that the use of rate control drugs demonstrated similar mortality at five years (primary outcome) to antiarrhythmic strategy.
  2. Rate control strategy also demonstrated decreased hospitalization and decreased adverse drug effects (secondary outcome) compared to antiarrhythmic drugs.

Background:

At the time of the publication of this article, the initial management of atrial fibrillation remained unclear. The risk of stroke and increased mortality of atrial fibrillation were well recognized, but the relative risks and benefits of the different management approaches was widely contested. The AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial aimed to determine whether rate control or rhythm control was superior in long-term outcomes in patients with atrial fibrillation. The trial was a randomized multicenter trial enrolling a total of 4060 patients with a fib who were randomized to either rhythm control or rate control strategies. Both strategies had equal mortality, while the rate control strategy showed decreased hospitalization and adverse drug effects. The strengths of this study were its robust size, the generalizability and the study design. However there was significant cross over and cross back in this study as it was an intention to treat study.

Details:

This was a multicenter RCT that enrolled 4060 patients over the age of 65 with atrial fibrillation. The patients were randomized at each of the sties to either rhythm control or rate control strategy. Both groups had similar demographic and baseline characteristics including rates of CHF, duration of a fib, and ejection fraction. The rhythm control strategy allowed treating physicians to use cardioversion as necessary and treat with any of 9 options of antiarrhythmics. The rate control strategy allowed physicians to decide between beta blockers, calcium channel blockers or digoxin. The rate control group was required to be on Coumadin, while the rhythm group was encouraged to be on anticoagulation especially during the initial month to 12 weeks after rhythm control.

This was an intention-to-treat study. There was significant cross over and cross back observed during the study in both arms, though significantly greater cross over in the antiarrhythmic group. These patients were followed for an average of 3.5 years.

The primary outcome of the study was mortality. There was no significant difference in mortality between the rate control and rhythm control groups (p=.08). The authors state there is a trend towards lower mortality in rate controlled group at 3.5 years. Graphically they depict a divergence of mortality as time passes with rate control group trending towards lower mortality. They did find that it was significantly more likely for patients in rhythm control group to be hospitalized and experience adverse drug effect. p (p<.001).

Limitations to the study include the amount of cross over present, the variety in medications used in the rhythm treatment strategy. In addition this study is only applicable to those aged 65 or greater, and cannot be generalized to all patients with atrial fibrillation.

Level of Evidence:

Level II based on ACEP grading scheme for therapeutic questions.

Source Articles:

Wyse, D G et al. “A Comparison of Rate Control and Rhythm Control in Patients With Atrial Fibrillation.” The New England Journal of Medicine 2002; 347.23: 1825-1833.

Resident Reviewer: Dr. Kazakin
Faculty Reviewer: Dr. Siket

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