Lenient Rate Control and Strict Rate Control for Atrial Fibrillation Appear to have Similar Cardiovascular Outcomes
Level 2: Mid-level evidence
Rate control and rhythm control strategies have been associated with similar rates of stroke and death in patients with chronic atrial fibrillation (Arch Intern Med. 2005;165:258-262, available at archinte.ama-assn.org/cgi/content/full/165/3/258, accessed April 14, 2010). A target heart rate of 60-80 beats/minute has been suggested by the American College of Cardiology (Circulation. 2006;114:e257-354, available at circ.ahajournals.org/cgi/content/full/114/7/e257, accessed April 14, 2010), but this recommendation is not based on studies with clinical outcomes. To address this issue, a randomized trial compared “lenient” rate control (resting heart rate <110 beats/minute) vs. “strict” rate control (resting heart rate <80 beats/minute and heart rate during moderate exercise <110 beats/minute) in patients with permanent atrial fibrillation (N Engl J Med. 2010 Mar 15 published online ahead of print, available at content.nejm.org/cgi/content/full/NEJMoa1001337, accessed April 14, 2010). The desired rate control was achieved through the use of beta blockers, calcium channel blockers, and digoxin, alone or in combination. The primary outcome was a composite of death, hospitalization for heart failure, stroke, major bleeding, or significant arrhythmic events. The three-year estimated cumulative incidence of the primary composite outcome was 12.9% with lenient control vs. 14.9% with strict control. There were no significant differences between groups in rates of dyspnea, fatigue, palpitations, or New York Heart Association functional class. The authors concluded that lenient rate control was as effective as strict rate control for the prevention of major cardiovascular events.