一、血管扩张药治疗心力衰竭的作用原理 1.减轻心脏后负荷及前负荷: 泵衰竭时,交感神经——肾上腺素系统兴奋,致外围血管特别是小动脉收缩,加重心室的射血阻力,使衰竭的心脏的排血量进一步减少。血管扩张药可使小动脉扩张,从而外围阻力降低,后负荷减轻,左心室的排血量增加;同时,血管扩张药也可扩张静脉,使静脉血管床容量增加,静脉回流量减少,因而心脏前负荷减轻,肺循环瘀血现象好转,故血管扩张药既可解除前向性衰竭,又 First, the role of vasodilator treatment of heart failure Principle 1. To reduce the post-cardiac load and the pre-load: pump failure, the sympathetic - adrenaline system excitability, caused by peripheral blood vessels, especially the contraction of arterioles, increased ventricular ejection resistance, So that the exhaustion of the heart to further reduce the amount of bleeding. Vasodilator drugs can dilate the arterioles, resulting in peripheral resistance decreased, after the load reduction, increased left ventricular blood output; the same time, vasodilators can also dilate the venous, the venous bed volume increased, reduced venous return, and thus the heart Preload reduced, the phenomenon of pulmonary circulation bleeding improved, so the vasodilator can lift the anterior failure, and