CHICAGO --- The heart drug digitalis is safe to give to patients with diastolic heart failure, a new study has found. Digitalis is the oldest and one of the least expensive drugs for the treatment of heart failure. However, its use in diastolic heart failure has been considered somewhat controversial based on results of small, anecdotal or non-randomized studies.
Noted heart failure authority Mihai Gheorghiade, M.D., was senior author on the study, which was published in the Aug, 1 issue of the journal Circulation. Gheorghiade is professor of medicine and associate chief of cardiology at Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital.
The study was the first to evaluate a treatment for diastolic heart failure, the most common type of heart failure in older adults, which is expected to increase as the population ages.
Results of the study were derived from a larger study of heart failure management conducted by the Digitalis Investigation Group in the United States and Canada.
Few drugs for diastolic heart failure have been tested in randomized studies, largely because, until recently, it wasn't recognized as a separate form of heart failure.
An estimated 5 million people in the United States have heart failure, about half of whom have diastolic heart failure, in which the heart muscle is stiff and doesn't take in enough blood with each beat. The other form of heart failure, systolic, occurs when the heart muscle is too weak to effectively pump blood out into the body.
Digitalis has been shown to have a number of benefits in systolic heart failure, including improving symptoms, quality of life, exercise tolerance and heart muscle contraction, as well controlling atrial fibrillation, the most common heart rhythm abnormality in heart failure.
“Our findings that digitalis is relatively safe in diastolic heart failure allow the drug to be prescribed if needed for atrial fibrillation, and to be evaluated further to see if it has other effects, such as improving symptoms, as it does for systolic heart failure,” Gheorghiade said.
The study involved patients with diastolic heart failure who were assigned to receive either digitalis (or digoxin, as it is also known) or a dummy drug. Digitalis slows the heart rate, helps eliminate fluid from body tissues and strengthens the contraction of the heart muscle. Most patients also were receiving diuretics and angiotensin-converting enzyme (ACE) inhibitors, two common treatments for heart failure.
Study participants were followed up for a little over three years, and study data were analyzed by a team of researchers from 10 medical centers. The investigators found that digitalis had no effect on death from heart failure or any cause, or on hospitalizations related to heart failure or any cause.
There was a trend - although not strong enough to discern if it occurred by chance or was associated with digitalis use - for patients to have reduced hospitalizations resulting from worsening heart failure. In addition, there was a trend for increased hospitalizations for unstable angina in this group of patients.
“These results are somewhat of a paradigm shift,” Gheorghiade said. “They show that although digitalis has no definite significant net benefit for diastolic heart failure, it also does no net harm. There is no need to avoid prescribing it, such as for atrial fibrillation, although newer drugs are often used first.”
Ali Ahmed, M.D., University of Alabama at Birmingham, was the lead author on the study. Collaborating were researchers from Washington University; National Heart, Lung and Blood Institute; Medical University of South Carolina; Cleveland Clinic Foundation; Case Western Reserve University; New York Medical College, Wake Forest University Baptist Medical Center; and the University of North Carolina at Chapel Hill.
This study was supported by grants from the National Heart, Lung and Blood Institute in cooperation with the Department of Veterans Affairs Cooperative studies Program. Glaxco Wellcome provided the study drugs.