Correspondence

Rhythm Control versus Rate Control for Atrial Fibrillation

N Engl J Med 2008; 359:1522October 2, 2008

Article

To the Editor:

In their article on rhythm control as compared with rate control for atrial fibrillation, Roy et al. (June 19 issue)1 conclude that “rate control should be considered a primary approach for patients with atrial fibrillation and congestive heart failure.” We believe this conclusion may be overstated because of some limitations that have not been emphasized. First, a significant proportion of patients in the rate-control group crossed over to the rhythm-control group because of worsening heart failure. Outcomes in this particular group would be of interest, since this condition is associated with a worse prognosis.2 Second, at 12 months, there were significantly fewer patients receiving beta-blockers in the rhythm-control group than in the rate-control group, and this difference could have influenced mortality.3 Finally, the follow-up should have included long-term Holter recordings, since patients with asymptomatic atrial fibrillation (which could have been missed with 12-lead electrocardiography4) could have benefited from a more aggressive strategy in the rhythm-control group. This study mainly reaffirms the ineffectiveness of antiarrhythmic medication instead of the true superiority of the rate-control strategy, as demonstrated a posteriori in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM).5 A personalized patient-based approach (including catheter ablation) still seems essential.

Sébastien Knecht, M.D.
Hôpital Cardiologique du Haut-L'Evêque, 33604 Bordeaux-Pessac, France
sebastien.knecht@chu-brugmann.be

Mark D. O'Neill, M.B., B.Ch., D.Phil.
St. Mary's Hospital, London W2A 1LA, United Kingdom

Thierry Verbeet, M.D.
Centre Hospitalier Universitaire Brugmann, 1020 Brussels, Belgium

5 References

1
Roy D, Talajic M, Nattel S, et al. Rhythm control versus rate control for atrial fibrillation and heart failure. N Engl J Med 2008;358:2667-2677
Full Text | Web of Science | Medline

2
Zannad F, Mebazaa A, Juilliere Y, et al. Clinical profile, contemporary management and one-year mortality in patients with severe acute heart failure syndromes: the EFICA study. Eur J Heart Fail 2006;8:697-705
CrossRef | Web of Science | Medline

3
The Cardiac Insufficiency Bisoprolol Study II (CIBIS-II): a randomised trial. Lancet 1999;353:9-13
CrossRef | Web of Science | Medline

4
Israel CW, Gronefeld G, Ehrlich JR, Li Y-G, Hohnloser SH. Long-term risk of recurrent atrial fibrillation as documented by an implantable monitoring device: implications for optimal patient care. J Am Coll Cardiol 2004;43:47-52
CrossRef | Web of Science | Medline

5
Corley SD, Epstein AE, DiMarco JP, et al. Relationships between sinus rhythm, treatment, and survival in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Study. Circulation 2004;109:1509-1513
CrossRef | Web of Science | Medline

Author/Editor Response

Knecht and colleagues question our conclusion that rate control should be a primary approach for patients with atrial fibrillation and congestive heart failure. Our conclusion was based on the demonstration of reduced hospitalization rates with rate control and equivalent mortality and morbidity, as compared with rhythm control.

With respect to the first point that Knecht and colleagues make, the most common reason for crossover from rate control to rhythm control was indeed worsening congestive heart failure, but data for patients who crossed over were analyzed in the group to which the patients had been assigned (intention-to-treat analysis). Furthermore, rates of death related to congestive heart failure were 37.5% higher in the rhythm-control group than in the rate-control group (P=0.11). Regarding beta-blockers, adjustment of the primary end point for the 10% difference in the proportions of patients receiving beta-blocker therapy, with the use of the 29% lower cardiovascular-related mortality with beta-blockers in the article cited by Knecht and colleagues,1 changes the hazard ratio for rhythm control as compared with rate control from 1.06 to 1.03, suggesting a minor role, if any, of beta-blocker therapy. Holter monitoring would probably have shown asymptomatic episodes of atrial fibrillation, which also occur after ablation of atrial fibrillation.

Advocates of rhythm control must recognize that all large, randomized trials to date, including ours, have failed to show significant population benefits of rhythm control. Ablation therapy has not been shown in adequately powered randomized trials to improve survival in any population of patients with atrial fibrillation.

Denis Roy, M.D.
Mario Talajic, M.D.
Stanley Nattel, M.D.
Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
d_roy@icm-mhi.com

1 References