Weissman N J, Nidorf S M, Guerrero J L, Weyman A E, Picard M H
Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston 02114.
J Am Coll Cardiol. 1995 Mar 1;25(3):605-9. doi: 10.1016/0735-1097(94)00450-5.
This study attempted to determine the benefit of a 5-min dobutamine stress echocardiographic stage versus a 3-min stage in a canine model.
Dobutamine stress echocardiography, as currently performed, uses a variety of different protocols. Among the many aspects of dobutamine stress echocardiographic protocols that vary is stage duration. Because dobutamine has specific pharmacodynamics, it is possible that stages of different durations may have different cardiovascular effects.
Paired dobutamine stress echocardiograms were obtained in 10 open chest instrumented dogs. The stage duration for the initial dobutamine stress echocardiogram was randomly allocated to either 3 or 5 min, and all hemodynamic and echocardiographic variables were allowed to return to baseline before the second dobutamine stress echocardiogram was obtained using the alternative stage duration. At each stage, heart rate, systolic blood pressure, coronary flow, myocardial wall thickness and left ventricular cavity area were recorded. Cavity obliteration, hypotension, ventricular tachycardia or a maximal dose of 40 micrograms/kg body weight per min served as the dobutamine stress echocardiographic end point.
At baseline, no difference was detected between the 3- or 5-min protocols for heart rate, systolic blood pressure, rate-pressure product, coronary blood flow, wall thickness or percent area change. Heart rate, systolic blood pressure and coronary flow increased more by the 10-micrograms/kg per min dose with the 5-min protocol than with the 3-min protocol. The dobutamine stress echocardiographic end points were achieved at a lower dobutamine dose (15.0 +/- 4.1 vs. 11.0 +/- 2.1 micrograms/kg per min [mean +/- SD], p = 0.01) with the longer stage duration.
In this canine model, a longer stage produced a greater hemodynamic effect at a lower peak dose. Thus, extending stage duration in clinical dobutamine stress echocardiography may achieve equivalent physiologic stress at lower doses and contribute to the optimization of dobutamine stress echocardiographic protocols.
本研究试图在犬类模型中确定5分钟多巴酚丁胺负荷超声心动图阶段与3分钟阶段相比的益处。
目前进行的多巴酚丁胺负荷超声心动图使用多种不同的方案。多巴酚丁胺负荷超声心动图方案的许多不同方面中，阶段持续时间是其中之一。由于多巴酚丁胺具有特定的药效学，不同持续时间的阶段可能具有不同的心血管效应。
对10只开胸插管犬进行配对多巴酚丁胺负荷超声心动图检查。初始多巴酚丁胺负荷超声心动图的阶段持续时间随机分配为3分钟或5分钟，在使用另一种阶段持续时间获得第二次多巴酚丁胺负荷超声心动图之前，所有血流动力学和超声心动图变量均恢复至基线。在每个阶段，记录心率、收缩压、冠状动脉血流、心肌壁厚度和左心室腔面积。腔室消失、低血压、室性心动过速或每分钟40微克/千克体重的最大剂量作为多巴酚丁胺负荷超声心动图终点。
在基线时，3分钟或5分钟方案在心率、收缩压、心率-血压乘积、冠状动脉血流、壁厚度或面积变化百分比方面未检测到差异。与3分钟方案相比，5分钟方案中每分钟10微克/千克剂量使心率、收缩压和冠状动脉血流增加更多。使用较长的阶段持续时间时，多巴酚丁胺负荷超声心动图终点在较低的多巴酚丁胺剂量下达到（15.0±4.1与11.0±2.1微克/千克每分钟[平均值±标准差]，p = 0.01）。
在该犬类模型中，较长的阶段在较低的峰值剂量下产生更大的血流动力学效应。因此，在临床多巴酚丁胺负荷超声心动图中延长阶段持续时间可能在较低剂量下实现等效的生理应激，并有助于优化多巴酚丁胺负荷超声心动图方案。
