However, a related editorial points out that three randomized trials have failed to demonstrate a mortality benefit with rhythm control, and asks “Can Observational Data Trump Randomized Trial Results? “
The authors of the study agree that the choice of rhythm control vs rate control treatment strategies for AF is controversial. To compare the long-term effectiveness of the two approaches in a general population of AF patients, they examined databases in Quebec, Canada, from 1999 to 2007.
Dr. Louise Pilote, with the Royal Victoria Hospital in Montreal, and colleagues identified 26,130 patients who were hospitalized for AF and had not been previously treated. Rhythm control drugs were initially prescribed for 6402 patients while 19,728 received rate control drugs. The outcome of the study was all-cause mortality.
The team found that mortality was similar in the two groups up to 4 years following initiation of treatment. However, it decreased steadily in the rhythm control group after 5 years. Specifically, the mortality hazard ratio was 0.89 after 5 years and 0.77 after 8 years with rhythm control versus rate control.
“The risk reduction associated with rhythm control therapy was even more pronounced among the subset of patients who maintained their initial treatment over longer periods of time,” Dr. Pilote and colleagues report, “suggesting that the use of rhythm control therapy may be beneficial for patients with AF in whom antiarrhythmic drugs are effective and well tolerated.”
The authors of the accompanying editorial, Dr. Thomas A. Dewland and Dr. Gregory M. Marcus of the University of California, San Francisco, say that while the findings are “provocative, they are insufficient to recommend a universal rhythm control strategy for all patients with AF. Randomization is a powerful tool that unfortunately cannot be reliably reproduced with statistical modeling.”
They conclude, “Randomized data from the ongoing, multinational Catheter Ablation vs Antiarrhythmic Drug Therapy for Atrial Fibrillation Trial (CABANA) will hopefully contribute to the long-standing debate regarding the optimal treatment paradigm for this common arrhythmia.”