Guazzi M D, Agostoni P G, Doria E, Loaldi A, Pepi M, Polese A
Angiology. 1985 Dec;36(12):857-66. doi: 10.1177/000331978503601204.
The initial antifailure efficacy of beta-adrenergic agonists is generally lost during prolonged treatment. The reasons are not fully understood. In 11 patients with advanced cardiac decompensation due to dilated cardiomyopathy, prenalterol, a selective beta 1 adrenergic agonist, improved the left ventricular contractility after acute intravenous and during prolonged oral administration. However, after periods of treatment ranging from 2 to 18 weeks, blood pressure and systemic vascular resistance were raised in each patient. These changes resulted in an increase of the left ventricular afterload which was such as to overwhelm the effects of the enhanced contractility, and to extinguish the initial improvement of the cardiac function and of the clinical condition. Stimulation of the presynaptical beta-receptors facilitating norepinephrine release or of the renin secretion by this beta 1 agonist, may be the causes of the systemic vasoconstriction and of the loss of effectiveness in the long run.
β-肾上腺素能激动剂的初始抗衰竭疗效在长期治疗过程中通常会丧失。其原因尚未完全明确。在11例因扩张型心肌病导致晚期心脏代偿失调的患者中，选择性β1肾上腺素能激动剂普瑞特罗在急性静脉注射及长期口服给药期间可改善左心室收缩力。然而，在2至18周的治疗期后，每位患者的血压和全身血管阻力均升高。这些变化导致左心室后负荷增加，足以抵消收缩力增强的作用，并消除心脏功能和临床状况的初始改善。这种β1激动剂刺激突触前β受体促进去甲肾上腺素释放或刺激肾素分泌，可能是全身血管收缩及最终丧失疗效的原因。
