Rhythm control is no better than rate control among patients with atrial fibrillation and congestive heart failure

June 19, 2008 By Vijayalakshmi Kunadian MBBS MD MRCP [mailto:vkunadian@perfuse.org]

New England Journal of Medicine-Montreal: New research demonstrates that rhythm control is no better than rate control in the management of patients with atrial fibrillation and congestive heart failure.

Atrial fibrillation (AF) can lead to heart failure due to loss of atrial contraction, impaired left ventricular filling and increased ventricular rate. Among patients with congestive heart failure, the incidence of AF is around 10-50%. It is not clear from several small studies if conversion to and maintenance of sinus rhythm (SR) among patients with AF and heart failure would improve survival. In a new study, Roy and coworkers explored this among patients with atrial fibrillation and congestive heart failure from 123 centers in Canada, United States, Europe, South America and Israel. Patients were recruited from May 2001 to June 2005 and the follow-up period ended on June 30, 2007.

This study was a multicenter randomized clinical trial consisting of patients with left ventricular ejection fraction 35% or less with symptoms of heart failure and atrial fibrillation. Patients with persistent AF for more than one year with reversible causes of heart failure and AF were excluded from the study. Patients in the rhythm control group were recommended to have electrical cardioversion within 6 weeks of failure to cardiovert with antiarrhythmic therapy. Amiodarone was the drug of choice for maintenance of SR. For rate control, beta-blockers with digoxin were used to achieve a target heart rate of <80 beats/minute. Angiotensin converting enzymes or angiotensin receptor blockers were recommended therapies for heart failure for all patients. The primary endpoint of this study consisted of time to death from cardiovascular causes. Patients were followed up at 3 weeks, 4 months and every 4 months until 48 months and subsequently every 6 months. The mean follow-up in the study was 37±19 months and the longest follow-up was 74 months.

There were 1376 patients in this trial. 682 were randomized to the rhythm control strategy and the remaining 694 were randomized to the rate control strategy. 82% of patients were men, 31% of patients were in NYHA class III/IV and the mean left ventricular ejection fraction was 27±6%. The primary endpoint occurred in 27% (n=182) of patients in the rhythm control group and 25% (n=175) in the rate control group (the unadjusted Hazard Ratio in the rhythm control group 1.06; 95% CI 0.86-1.30, p=0.59). After adjustment for baseline characteristics, the HR was 1.05 (95% CI 0.85-1.29, p=0.67).

There was no significant difference in the secondary endpoints including death from any cause [32% vs. 33%, HR 0.97 (95% CI 0.80-1.17, p=0.73)], stroke [3% vs. 4% HR 0.74 (95% 0.40-1.35, p=0.32)], worsening heart failure [28% vs. 31%, HR 0.87 (95% CI 0.72-1.06, p=0.17)] and a composite of death, stroke and worsening heart failure [43% vs. 46%, HR 0.90, (95% CI 0.77-1.06, p=0.20)] between the rhythm control and the rate control groups. The mean actuarial annual rate of death from cardiovascular causes for all patients was 8%. The rate of hospitalization for AF (14% vs. 9%, p=0.001), bradyarrhythmias (6% vs. 3%, p=0.02) and electrical cardioversions (59% vs. 9%, p<0.001) were more frequent in the rhythm control group compared with the rate control group.

The investigators concluded that there was no benefit of the rhythm control strategy over the rate control strategy in terms of reduction in the rates of death from cardiovascular causes and based on the results of this study they recommend that the rate control strategy should be considered a primary approach for patients with AF and congestive heart failure.

Source

 * 1) http://content.nejm.org/cgi/content/short/358/25/2667?query=TOC