 The RALES study has shown that spironolactone reduces the risk of morbidity and mortality both from progressive heart failure and sudden death, in patients with NYHA III or IV heart failure. This favourable effect was clearly independent from a diuretic effect. Antialdosterone drugs may be effective because they opposes the effects of aldosterone on sodium retention, loss of magnesium and potassium, sympathetic activation, baroreceptor function and vascular compliance. Antialdosterone treatment may also antagonize the effect of aldosterone in promoting cardiac fibrosis. In a RALES substudy baseline serum PIIINP, a marker of cardiac fibrosis synthesis showed an independent negative correlation with survival and CHF hospitalizations in the placebo group. Therefore it seems interesting to evaluate the effect of an Aldosterone receptor blocker on progression of left ventricular dysfunction in patients with mild heart failure assuming standard therapy. 