The group was divided into those with sustained tachycardia and those without it. The first group was randomly assigned in equal proportions to antiarrhythmic therapy or no therapy, with a small number receiving implantable cardioverter defibrillators (ICDs) if they didn't respond to antiarrhythmic drugs. The group without sustained tachycardia received no antiarrhythmic therapy and was recorded in a registry.
The analysis reviewed 2,096 patients (702 randomized and 1,394 registry patients) enrolled at 85 sites in the United States and Canada between November 1990 and October 1996. Of them, 799 patients received beta blockers 314 in the randomized group and 485 in the registry group. Of patients who didn't receive a beta blocker, 388 were in the randomized group and 909 were in the registry. Researchers found that death rates for beta blocker patients were 16 percent at two years and 34 percent at five years, significantly lower than the death rates of 27 percent at two years and 50 percent at five year for patients not receiving beta blockers.
The life-saving properties of beta blockers were consistent across the spectrum of study patients, such as those with and without inducible tachycardia. Patients with ICDs were the exception.
In contrast to the positive effect that beta blockers had on the overall death rate, the drugs didn't significantly reduce arrhythmic death or cardiac arrest, the study's primary end points. However, the authors note, "there was a trend toward fewer arrhythmic events and improved survival in those treated with
Contact: Carole Bullock
American Heart Association