[Conversion enzyme inhibitors in the treatment of chronic congestive cardiac failure. Physiopathologic bases of their use].

The treatment of chronic congestive heart failure relies on positive inotropic, diuretic, venous and arterial vasodilating drugs. Several factors are involved in the physiopathology of chronic congestive heart failure such as venous and arterial vasoconstriction mediated by the adrenergic system and/or the renin-angiotensin system which increases concomitantly the extracellular volume. These factors are initially compensatory of the low-cardiac output, but aggravate the heart failure on a long-term and are the basis for the use of vasodilating drugs and diuretics. Among vasodilating drugs the converting enzyme inhibitors are of special interest since they inhibit the renin-angiotensin system which is directly involved in the physiopathology of heart failure. On the other hand, they act both as venous and as arterial vasodilators and are generally better tolerated than pure venous or pure arterial vasodilating drugs. They are also better tolerated than the oral inotropic drugs commonly used (mainly digitalis) whose efficacy is controversial in patients being in sinus rhythm. The use of converting enzyme inhibitors, which is now restricted to the more severe cases of chronic heart failure, may be enlarged in the future to the first steps of heart failure, especially if a beneficial effect of these drugs on the long term survey may be proved.