Treatment of heart failure comprises the use of diuretics, vasodilators and inotropic substances. Unloading of the heart and the circulation in hydropic states is classically achieved with diuretics. The retention of salt and water in chronic heart failure requires chronic treatment with diuretics. This mode of treatment is basic to all forms of hydropic heart failure. Inotropic substances such as digitalis glycosides, sympathomimetic amines or phosphodiesterase inhibitors have certain disadvantages: Inotropic stimulation increases energy demand of the working heart muscle. Most of the substances used today increase energy consumption inordinately, thereby decreasing economy of myocardial contraction. This aspect calls for caution in the application of these substances in chronic heart failure, although they seem indispensable (sympathomimetic amines) in acute hypotensive failure and shock. Digitalis glycosides, basically suited for longterm treatment, exert only mild inotropic effects. In addition inotropic stimulation brings with it arrhythmogenic effects. All inotropic substances can induce ventricular arrhythmias already at therapeutic levels. Vasodilating substances have found increasing acceptance as a particularly useful and safe group of drugs for the treatment of heart failure. Nitrates: With the different nitrate compounds and nitrate preparations an effective venodilation with preload reduction can safely be achieved. At higher doses, arteriolar also dilatation can be induced. Although tolerance may be a problem with chronic application, this can be avoided with prudent dosing. The strong venodilating property makes these drugs together with their rapid onset of action ideally suited for the treatment of acute heart failure with pulmonary congestion.(ABSTRACT TRUNCATED AT 250 WORDS)