A Neurohormonal Modulator in Heart Failure?
نویسنده
چکیده
Clinical Use of Digitalis Glycosides The potential benefit of digoxin therapy in heart failure patients is thought to be related to its positive inotropic effect that increases cardiac output and thereby decreases ventricular filling pressures.2 Although digoxin is undoubtedly an inotropic agent in tissue preparations,3 this effect, in contrast to other inotropic agents, is not consistently translated into improved hemodynamics in the intact animal or in humans.4 For example, in normal volunteers5 or in patients with left ventricular dysfunction and normal6 or normalized hemodynamics with other therapies,7 no significant increase and even a decrease8 in cardiac output may occur. This paradox was initially attributed to peripheral vasoconstrictor9,10 effects of digitalis compounds that increase afterload and thereby attenuate or mask its inotropic effect. However, peripheral vasoconstriction is transient1' and is manifested only after rapid intravenous administration of digitalis preparations and does not fully explain the failure to augment cardiac function in patients with normal hemodynamics. In contrast, when digoxin is given acutely to patients with left ventricular systolic dysfunction and abnormal central hemodynamics,12-14 there is a significant increase in cardiac output and a decrease in pulmonary capillary wedge pressure and systemic vascular resistance. It appears, therefore, that the acute hemodynamic response to digoxin is inversely proportional to the degree of underlying hemodynamic impairment.7 Several studies have shown that long-term digoxin therapy improves left ventricular function and is clini-
منابع مشابه
Digitalis Glycosides Diuretic Therapy for Heart Failure Vasodilator Therapy Aldosterone Receptor Antagonists Beta-adrenergic Receptor Blockers Anticoagulation Statins Medications
Heart failure due to a decline in cardiac performance initiates compensatory neurohormonal mechanisms in an effort to maintain systemic perfusion. Ongoing neurohormonal activation may have deleterious consequences for cardiac performance, ventricular remodeling, myocardial function, and heart failure progression. The fundamental objective of modern medical therapy for heart failure is to reliev...
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