[Neurohormonal factors in heart failure (and III)]

Heart failure is a physiopathological condition, with an increasing incidence and prevalence, involving the action of a series of mechanisms known as "compensators", which are phylogenetically ready to normalize minute volume and blood pressure. These mechanisms include the activation of a series of neurohormonal systems: the sympathetic nervous system, the aldosterone renin-angiotensin system, vasopressin arginine, endothelin, which are basically vasoconstrictors, with the counterpoint of other vasodilator systems, such as the endothelial relaxation factor, certain prostaglandins and the bradykinin-kallikrein system, which modulate global response. The authors review the physiopathology of each of these system, as well as their significance in the diagnosis and prognostic evaluation of heart failure. We analyze the possible deleterious effects of neurohormonal activation, anatomically and at cardiovascular function level, and try to determine if they are capable of explaining the evolution and progression of heart failure, in a truly vicious circle, up until the irreversible heart failure phase. We review the current importance of the inhibition of the aldosterone renin-angiotensin system in the prophylaxis and treatment of heart failure. Furthermore, we describe the present-day value of the inhibition of the sympathetic nervous system in some forms of heart failure. We also analyze the different pharmacological treatments for heart failure: diuretics, inotropic agents, vasodilators (in their different pharmacological types), paying particular attention to their action on neurohormonal systems and their implications in the prognosis and evolution of heart failure.