Hammond H K, McKirnan M D
Veterans Affairs Medical Center-San Diego, California 92161.
J Am Coll Cardiol. 1994 Feb;23(2):475-82. doi: 10.1016/0735-1097(94)90436-7.
The present study was performed to determine the mechanisms for catecholamine-induced wall motion abnormalities and to compare the diagnostic efficacy of two catecholamines: arbutamine and dobutamine.
Catecholamine stress echocardiography is used to induce regional wall motion abnormalities for the detection of coronary artery disease, but the mechanism by which these abnormalities occur is unknown.
Ten pigs were instrumented with left circumflex coronary artery ameroid constrictors, sonomicrometers to measure transmural wall thickening in the left circumflex (ischemic) and left anterior descending (control) coronary artery beds and a pressure gauge to measure left ventricular pressure and its first derivative (dP/dt). Myocardial blood flow was measured by microspheres.
At 38 +/- 6 days (mean +/- SEM) after surgery, percent wall thickening was normal at rest in both beds but abnormal in the left circumflex coronary artery bed during atrial pacing. These findings were associated with reduced myocardial blood flow in the ischemic bed during atrial pacing. Dobutamine infusion increased percent wall thickening, with no differences between the two beds (p = 0.63). In contrast, arbutamine infusion increased percent wall thickening only in the nonischemic bed, with no effect on percent wall thickening in the ischemic bed (p = 0.03). Although the endocardial/epicardial blood flow ratio tended to be reduced in the left circumflex artery bed during catecholamine infusion (p = 0.07), both agents were similar in this effect. Despite differences in function between the beds, there was no difference in transmural myocardial blood flow between the two beds during catecholamine infusion. When examined at matched metabolic demands, arbutamine elicited greater differences in percent wall thickening than dobutamine between the two beds (p < 0.01).
Arbutamine was able to provoke regional differences in function in a manner superior to dobutamine. This occurred independently of altered transmural myocardial blood flow or differences in hemodynamic effects between the agents. Differences in their inotropic properties may be important in explaining their different effects on ischemic myocardium.
进行本研究以确定儿茶酚胺诱导室壁运动异常的机制，并比较两种儿茶酚胺（阿巴美明和多巴酚丁胺）的诊断效能。
儿茶酚胺负荷超声心动图用于诱导局部室壁运动异常以检测冠状动脉疾病，但这些异常发生的机制尚不清楚。
对10头猪植入左旋冠状动脉阿梅氏环缩窄器、用于测量左旋（缺血）和左前降支（对照）冠状动脉床透壁心肌增厚的超声微测仪以及用于测量左心室压力及其一阶导数（dP/dt）的压力计。通过微球测量心肌血流量。
术后38±6天（平均值±标准误），两个冠状动脉床静息时的心肌增厚百分比均正常，但在心房起搏期间左旋冠状动脉床异常。这些发现与心房起搏期间缺血床心肌血流量减少有关。输注多巴酚丁胺可增加心肌增厚百分比，两个冠状动脉床之间无差异（p = 0.63）。相比之下，输注阿巴美明仅增加非缺血床的心肌增厚百分比，对缺血床的心肌增厚百分比无影响（p = 0.03）。尽管在儿茶酚胺输注期间左旋冠状动脉床的心内膜/心外膜血流比值趋于降低（p = 0.07），但两种药物在这方面的作用相似。尽管两个冠状动脉床的功能存在差异，但在儿茶酚胺输注期间两个冠状动脉床的透壁心肌血流量无差异。在匹配的代谢需求下进行检查时，阿巴美明在两个冠状动脉床之间引起的心肌增厚百分比差异比多巴酚丁胺更大（p < 0.01）。
阿巴美明能够以优于多巴酚丁胺的方式引发功能上的局部差异。这一现象独立于透壁心肌血流量的改变或药物之间血流动力学效应的差异而发生。它们变力特性的差异可能对解释它们对缺血心肌的不同作用很重要。
