A New Approach to Therapy for Atrial Fibrillation

A large multicenter study has found that restoring and maintaining normal heart rhythm in patients with atrial fibrillation (AF) prevents no more deaths than merely controlling the rate at which the heart beats. A similar but smaller study found that 25% fewer patients with AF died of a heart-related cause when given rate controlling therapy, compared to rhythm control. The studies were published in the December 5, 2002, issue of The New England Journal of Medicine.

The most frequently used initial therapy for AF is a strategy to restore and maintain a normal heart rhythm. However, the new study found that this strategy not only prevents no more deaths but may have some disadvantages, including more hospitalizations and adverse drug effects. Furthermore, the rhythm approach does not result in a lower risk of stroke, improved quality of life, or improved cognitive function as presumed.

The study involved 4,060 patients at 213 sites, all with AF and at least one other risk factor for stroke or death. Patients were randomly assigned to a rhythm control or rate control treatment strategy and were followed for an average of three and a half years. Both groups were given warfarin. The rhythm control group was given antiarrhythmic drugs such as amiodarone, sotalol, and propafenone to try to convert the heart back to normal rhythm and then maintain normal rhythm. Rhythm control in some cases involved an electrical shock, or cardioversion. The rate control group, in contrast, received drugs such as digoxin, beta blockers, and calcium channel blockers. Strokes were uncommon in both groups. During the study, 1,374 patients in the rhythm control group were hospitalized, compared to 1,220 in the rate control group.

"The rate control approach may also be less costly due to a difference in the number of hospitalizations,” said D. George Wyse, M.D., professor of cardiology at the University of Calgary (Canada) and chair of the study's steering committee. Dr. Wyse also noted that although statistically there was no significant difference between the two groups' death rates, there was a trend toward better survival in the rate control group after the first year. The study was supported by the US National Heart, Lung, and Blood Institute ().

A second, smaller study led by Dr. Isabelle C. Van Gelder, of the University Hospital in Groningen (The Netherlands; www.med.rug.nl), involved 522 patients. Following an average of 2.3 years, only 44 (17.2%) of the rate control group had died, compared to 60 (22.6%) patients in the rhythm control group.





Related Links:
NHLBI
U. Hospital Groningen