Hydralazine is a smooth muscle relaxant and a potent arteriolar dilator. The major hemodynamic effect of hydralazine in patients with heart failure are increased cardiac output and stroke volume, and decreased vascular resistance without any significant change in pulmonary and systemic venous pressure. Hydralazine also produces beneficial hemodynamic effects in patients with mitral and aortic regurgitation and in some patients with large ventricular septal effect with reduced systemic output. However, the role of long-term hydralazine therapy in these patients remains uncertain. In many patients with chronic heart failure with low cardiac output, hydralazine produces sustained beneficial hemodynamic and clinical effects. The long-term prognosis of patients with chronic heart failure, however, remains unchanged, although certain subsets of patients appear to have better prognoses than others during long-term hydralazine therapy.
肼屈嗪是一种平滑肌松弛剂和强效小动脉扩张剂。肼屈嗪对心力衰竭患者的主要血流动力学作用是心输出量和每搏输出量增加，血管阻力降低，而肺和体循环静脉压力无明显变化。肼屈嗪对二尖瓣和主动脉反流患者以及一些心室间隔缺损较大且心输出量降低的患者也产生有益的血流动力学作用。然而，长期使用肼屈嗪治疗在这些患者中的作用仍不确定。在许多心输出量低的慢性心力衰竭患者中，肼屈嗪产生持续有益的血流动力学和临床效果。然而，慢性心力衰竭患者的长期预后并未改变，尽管某些亚组患者在长期使用肼屈嗪治疗期间似乎比其他患者有更好的预后。
