Value of digoxin in heart failure and sinus rhythm: new features of an old drug?
Digoxin has been a controversial drug since its introduction >200 years ago. Although its efficacy in patients with heart failure and atrial fibrillation is clear, its value in patients with heart failure and sinus rhythm has often been questioned. In the 1980s, reports of some large-scale trials indicated that digoxin, with or without vasodilators or angiotensin-converting enzyme inhibitors, reduced signs and symptoms of congestive heart failure and improved exercise tolerance. This beneficial influence was mainly found in patients with more advanced heart failure and dilated ventricles, whereas the effect in those with mild disease appeared to be less pronounced. In the last few years, new data have shown that digoxin may also have clinical value in mild heart failure, either when used in combination with other drugs or when administered alone. As neurohumoral activation has increasingly been recognized to be a contributing factor in the disease progression of chronic heart failure, the modulating effects of digoxin on neurohumoral and autonomic status have received more attention. Also, there is evidence that relatively low doses of digoxin may be at least as effective as higher doses and have a lower incidence of side effects. Further, the recognition that the use of digoxin too early after myocardial infarction may be harmful and the development of other drugs, in particular angiotensin-converting enzyme inhibitors, have obviously changed the place of digoxin in the treatment of chronic heart failure. The large-scale survival trial by the Digitalis Investigators Group (DIG), whose preliminary results have recently been presented, has shown that although digoxin has a neutral effect on total mortality during long-term treatment, it reduces the number of hospital admissions and deaths due to worsening heart failure. The potentially new features of the old drug digoxin are discussed in this review.