Congestive Heart Failure

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Abstract
Left ventricular systolic dysfunction is associated with neurohormonal activation which contributes to progressive ventricular remodeling and worsening clinical heart failure. Renin-angiotensin-aldosterone and sympathetic nervous systems are activated, not only in patients with clinically overt heart failure, but also in patients with asymptomatic or minimally symptomatic left ventricular systolic dysfunction. Activation of the angiotensin and adrenergic systems produces deleterious effects on systemic and coronary hemodynamics, promotes myocyte hypertrophy and fibroblast growth, and myocyte necrosis and apoptosis. Thus, therapy of heart failure should consist of pharmacologic agents not only to relieve symptoms but also to prevent and attenuate ventricular remodeling and progressive heart failure, thereby improving prognosis. In patients who are symptomatic, ACE inhibitors along with digitalis and diuretics as initial therapy (triple therapy) have the greater potential to improve exercise tolerance and decrease the incidence of treatment failure compared with diuretics alone or a combination of diuretics and digitalis. Diuretics alone should not be considered for long-term therapy as plasma renin activity, angiotensin II, aldosterone, norepinephrine and vasopressin levels may increase. ACE inhibitors decrease mortality in patients with heart failure resulting from left ventricular systolic dysfunction. The results of presently available studies indicate that angiotensin II receptor blockers (ARBs) do not provide any advantage over ACE inhibitors regarding survival benefit but may be better tolerated. Long-term adrenergic inhibition with the use of ß-adrenoceptor antagonists added to ACE inhibitors is associated with attenuation of ventricular remodeling, improvement in ventricular function and clinical class and survival of patients with symptomatic systolic left ventricular failure. Thus, initial pharmacotherapy for systolic heart failure should consist of: (i) maximal tolerated dosages of ACE inhibitors; (ii) ARBs if ACE inhibitors are not tolerated because of intractable cough or angioedema; (iii) adequate dosages of hydralazine and isosorbide dinitrate if ACE inhibitors or ARBs are not tolerated; (iv) relatively low dosages of digoxin (serum concentrations of ≤ 1.0 ng/dl) if not contraindicated; and (v) diuretics to relieve congestive symptoms. Addition of spironolactone to ACE inhibitors can result in a significant reduction in the risk of sudden death in patients with symptomatic severe heart failure. Myocardial infarction resulting from ischemic heart disease is the most common cause of systolic left ventricular failure and the therapeutic modalities with potential to reduce the risks of myocardial infraction, such as risk factor modification, adequate control of diabetes and hypertension, antiplatelet agents and lipid-lowering agents, should also be included in the initial therapy.