ALDOSTERONE METABOLISM IN CARDIAC FAILURE

SUMMARY The place of aldosterone in the pathogenesis of cardiac failure remains controversial. In order to clarify this problem, aldosterone metabolism has been studied before and after therapy in 11 cases of untreated cardiac failure, and repeatedly during therapy in seven others. The studies, which have included measurement of the aldosterone secretion rate, plasma metabolic clearance rate, ratio of the urinary metabolites and calculation of the plasma aldosterone content, have been correlated with sodium and potassium balance measurements. The aldosterone secretion rate and plasma aldosterone levels are normal in untreated cardiac failure, but are abnormally elevated during successful therapy. Digitalis may not cause a significant change in these levels, but diuretic therapy causes a marked rise. The metabolic clearance rate of aldosterone is impaired in cardiac failure, and this may contribute to a raised plasma level. The secretion rate and plasma levels are particularly related to sodium status. These observations suggest that aldosterone plays little part in the renal conservation of sodium in cardiac failure, and that hyperaldosteronism, when present, is secondary to therapy.