Hinds J E, Hawthorne E W
Am J Cardiol. 1975 Dec;36(7):894-901. doi: 10.1016/0002-9149(75)90079-x.
The cardiac dynamic consequences were evaluated of constant infusions of dobutamine and isoproterenol at graded dose levels into conscious, healthy instrumented dogs. Measurements were made of simultaneous changes in left ventricular internal diameter, pressure, aortic pressure and rate of rise of left ventricular pressure(dP/dt), as well as the left ventricular electrogram. From these primary variables, derived variables were computed using programs in a minicomputer system. The data showed that, with increasing doses of dobutamine there were significant linear increases in all measured indexes of myocardial contractility, such as the rate of rise of left ventricular pressure at a developed isovolumic pressure of 40 mm Hg (dP/dt/P40), mean velocity of left ventricular fiber shortening, ejection fraction and stroke work. These changes in myocardial contractility occurred without changes in end-diastolic volume, mean aortic pressure or heart rate when dobutamine was infused in doses of 5 to 20 mug/kg per min. Isoproterenol also produced linear changes in indexes of myocardial contractility but in doses of 0.02 to 0.10 mug/kg per min, it produced a significantly higher heart rate at any given level of contractility than that produced by dobutamine. Cardiac minute work (heart rate X stroke work) was increased by both drugs. However, with infusions of isoproterenol the amount of cardiac minute work was significantly limited because of the changes in heart rate, whereas with dobutamine cardiac minute work could be increased to a higher level as a function of changes in myocardial contractility alone without changes in heart rate. These data suggest that dobutamine selectively increases myocardial contractility.
在清醒、健康且装有仪器的犬类中，以分级剂量水平持续输注多巴酚丁胺和异丙肾上腺素，评估其对心脏动力学的影响。同时测量左心室内径、压力、主动脉压力和左心室压力上升速率（dP/dt）以及左心室电图的变化。根据这些主要变量，使用小型计算机系统中的程序计算得出派生变量。数据显示，随着多巴酚丁胺剂量的增加，所有测量的心肌收缩性指标均呈显著线性增加，例如在40 mmHg的等容收缩压下左心室压力上升速率（dP/dt/P40）、左心室纤维缩短平均速度、射血分数和每搏功。当以5至20 μg/kg每分钟的剂量输注多巴酚丁胺时，心肌收缩性的这些变化发生时，舒张末期容积、平均主动脉压力或心率均无变化。异丙肾上腺素也使心肌收缩性指标呈线性变化，但在0.02至0.10 μg/kg每分钟的剂量下，在任何给定的收缩性水平下，它产生的心率均显著高于多巴酚丁胺。两种药物均增加了心脏每分钟功（心率×每搏功）。然而，输注异丙肾上腺素时，由于心率变化，心脏每分钟功的增加量受到显著限制，而输注多巴酚丁胺时，心脏每分钟功可仅作为心肌收缩性变化的函数增加到更高水平，而心率无变化。这些数据表明，多巴酚丁胺可选择性地增加心肌收缩性。
