血管扩张药是最近用于治疗充血性心力衰竭的又一类药物。心衰的特征是心排出量减少和体循环血管阻力增加,后者又使左心室射血阻抗增加,进一步减少心排出量。血管扩张药通过扩张外周血管降低左心室的射血阻抗来打破这一恶性循环。虽然多数血管 Vasodilators are another recent class of drugs used to treat congestive heart failure. Heart failure is characterized by a decrease in cardiac output and an increase in systemic vascular resistance, which in turn increases left ventricular ejection resistance and further decreases cardiac output. Vasodilators break this vicious cycle by dilating peripheral blood vessels and lowering the ejection resistance of the left ventricle. Although most blood vessels