Findings alleviate concerns of physicians reluctant to prescribe beta-blockers because of cardiovascular adverse effects

Beta-blocker therapy in patients with heart failure is well tolerated and associated with fewer overall withdrawals and less heart failure deterioration than placebo, according to a new article in the Archives of Internal Medicine, one of the JAMA/Archives journals.

Beta-blockers are a class of drugs that block beta-adrenergic substances, help relieve stress on the heart, slow the heart beat, lessen the force with which the heart muscle contracts, and reduce blood vessel contraction in the heart, brain, and throughout the body. According to information in the article, beta-blockers substantially improve survival in patients with chronic heart failure (HF) with left ventricular systolic dysfunction (failure of the left ventricle to contract strongly enough to pump blood out to the body). But concerns about cardiovascular adverse effects may deter physicians from prescribing this therapy.

Dennis T. Ko, M.D., of the University of Toronto, Ontario, Harlan Krumholz, M.D., of Yale University School of Medicine, and colleagues performed an overview of randomized trials comparing beta-blockers with placebo in patients with HF to quantify the risks of adverse effects. Trials were identified by electronic searches of the MEDLINE database from 1966 to 2002. Nine trials involving 14,594 patients with follow-up periods ranging from six to 24 months were included in the overview.

"Although beta-blocker therapy was associated with hypotension [low blood pressure], dizziness, and bradycardia [slow heart beat], the absolute increases in risk were small, and overall fewer patients were withdrawn from beta-blocker therapy than from placebo," the authors write.

Beta-blocker therapy was associated with a significant 27 percent relative reduction in all-cause mortality and absolute risk reduction of 34 deaths per 1,000 patients per year. It was associated with significant absolute annual increases in risks of hypotension (11 per 1,000), dizziness (57 per 1,000), and bradycardia (38 per 1,000). It was associated with a reduction in all-cause withdrawal of medication (14 per 1,000), HF hospitalizations (40 per 1,000), and worsening HF (52 per 1,000).

"The principal finding of our quantitative overview is that despite concerns about adverse effects, fewer patients with HF assigned to receive beta-blockers were withdrawn from therapy than were those assigned to receive placebo," the authors write. "This difference was primarily owing to a reduction of worsening HF associated with beta-blocker therapy."

"Our findings should alleviate concerns of physicians who are reluctant to prescribe beta-blockers because of their cardiovascular adverse effects and support the implementation of this lifesaving therapy to appropriate candidates with HF," they conclude.