Rate control in atrial fibrillation
Author + information
- Isabelle C. Van Gelder, MD (i.c.van.gelder{at}thorax.azg.nl),
- Michiel Rienstra, MD,
- Maarten P. Van den Berg, MD and
- Dirk J. Van Veldhuisen, MD, FACC
We read with great interest the substudy of the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) investigators on the approaches to control rate in atrial fibrillation (AF) (1). Recent studies show that rate control may be adopted as first-choice therapy in a variety of patients with AF (2,3). The optimal level of heart rate during AF is, however, still unknown.
In the AFFIRM study, in accordance with the guidelines (4), a strict rate-control approach was applied that includes a resting heart rate ≤80 beats/min and either a 6-min walk test heart rate ≤110 beats/min or a mean heart rate on a 24-h Holter recording ≤100 beats/min, in combination with a maximum heart rate ≤110% of predicted maximum heart rate. The present study shows that this (strict) rate-control approach can be successfully achieved in two-thirds of the patients and that, in line with previous data, beta-blockers are most effective to accomplish this goal (5). Serious adverse effects were uncommon. However, to obtain adequate rate control, atrioventricular node ablation and pacemaker implantation was performed in 108 of the 2,027 patients (5.3%), and an additional 147 patients (7.3%) had a pacemaker implanted for symptomatic bradycardia. In comparison, in the RAte Control versus Electrical cardioversion (RACE) study, a more lenient rate-control approach was followed (resting heart rate <100 beats/min) (3). In that study, 46% of the patients were treated with a beta-blocker. Severe drug adverse effects were also rare (0.8%). In contrast to the AFFIRM study, however, a pacemaker was implanted in only 3 of the 256 patients (1.2%, all after atrioventricular node ablation).
Unfortunately, the AFFIRM investigators give no data on the influence of the level of rate control on mortality and morbidity. Therefore, it still, remains unknown whether strict rate control is associated with an improved prognosis. To answer the question of which approach to rate control is most effective we will start the RAte Control Efficacy in permanent atrial fibrillation study (RACE II).
- American College of Cardiology Foundation
