AHA 2008: Exercise may be the prescription for heart failure

New Orleans-An aerobic exercise program modestly reduces death and hospitalization in patients with chronic heart failure, according to results from a study funded by the National Heart, Lung, and Blood Institute.

Numerous studies had suggested that exercise training improved peak oxygen consumption, function, exercise capacity, and quality of life but were considered inconclusive because of the small number of patients enrolled in each, the lack of control groups, and limited safety data. In fact, most insurers and government health programs do not cover exercise training for heart failure patients because of an absence of clear benefit, says Christopher O’Connor, MD, a co-investigator of the study.

More than 2,000 patients with class II to IV heart failure were randomized to exercise training aimed at increasing workout intensity or usual care in which they were encouraged to exercise but without any specific program. The group assigned to the intervention had 36 supervised training sessions (goal: three times per week) for up to 6 months, using heart rate reserve as a guide to intensity, before transitioning to a home exercise program, during which they were asked to exercise five times per week. The exercise program consisted of walking on a treadmill, walking independently, or using a stationary bicycle.

More than 90 percent of the patients in each arm received optimal medical care, defined as evidence-based medical therapy.

Three months into the study, more than half (52 percent) of the group assigned to the intervention were exercising at least three times a week for 40 minutes per session, a rate that held steady for the first year before dropping slightly in the second year of the study.

After a median follow-up of 2.5 years, the intervention group had reduced rates of three composite clinical endpoints: all-cause mortality/hospitalization, cardiovascular mortality/cardiovascular hospitalization, and cardiovascular mortality/heart failure

hospitalization, but none of these reductions achieved statistical significance. After adjusting for key prespecified prognostic variables, however, the investigators found a significant 11 percent reduction (P = 0.03) in the primary endpoint of all-cause mortality and hospitalization in the intervention group, and a significant 15 percent reduction (P = 0.03) in a secondary endpoint of cardiovascular mortality and heart failure hospitalization.

“Perhaps the most important finding is that exercise training is at this degree is safe,” says Dr. O’Connor, director of the Heart Center at Duke University Medical Center, Durham, NC. Cardiovascular events occurred in 40 percent of the usual care group and 37 percent of the group assigned to exercise training.

“Patients had a similar rate of ICD [implantable cardioverter-defibrillator] firing,” he adds. “Deaths identified as possibly occurring within 3 hours of physical activity were low and similar in both groups.”

[The results of the study were presented by co-investigator David Whellan, MD (pictured) associate professor of medicine (cardiology) at Thomas Jefferson Medical School in Philadelphia.]