Ishizaka S, Asanoi H, Kameyama T, Sasayama S
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Int J Cardiol. 1991 Apr;31(1):51-8. doi: 10.1016/0167-5273(91)90267-s.
To evaluate the effects of inotropic stimulation on ventriculo-arterial coupling, we determined both the slope of the end-systolic pressure-volume relationship (ventricular elastance) and the slope of end-systolic pressure-stroke volume relationship (arterial elastance) at rest and during dobutamine infusion (5 micrograms/kg/min). We also determined stroke work, end-systolic potential energy and the ventricular work efficiency defined as stroke work per pressure volume area (stroke work + potential energy). In the resting state, ventricular elastance was lower than arterial elastance and work efficiency was about 59.7 +/- 9.3% (mean +/- SD). This condition is remote from the point where stroke work or mechanical efficiency is optimal. Enhanced ventricular elastance by 41% with dobutamine resulted in a significant reduction in both left ventricular end-diastolic and end-systolic volumes and was accompanied by the reduction in arterial elastance by 23%. Consequently, the ratio of arterial elastance to ventricular elastance decreased from 1.43 +/- 0.57 to 0.82 +/- 0.47, which resulted in an increase in stroke work, a decrease in potential energy and hence a marked increase in work efficiency. Thus, inotropic stimulation of depressed hearts could modulate ventriculo-arterial coupling towards optimization of either stroke work or mechanical efficiency.
为评估变力性刺激对心室-动脉耦联的影响，我们测定了静息状态以及静脉输注多巴酚丁胺（5微克/千克/分钟）期间的收缩末期压力-容积关系斜率（心室弹性）和收缩末期压力-每搏量关系斜率（动脉弹性）。我们还测定了每搏功、收缩末期势能以及定义为每压力容积面积每搏功（每搏功+势能）的心室作功效率。在静息状态下，心室弹性低于动脉弹性，作功效率约为59.7±9.3%（平均值±标准差）。这种情况远离每搏功或机械效率最佳的点。多巴酚丁胺使心室弹性增强41%，导致左心室舒张末期和收缩末期容积显著减小，并伴有动脉弹性降低23%。因此，动脉弹性与心室弹性之比从1.43±0.57降至0.82±0.47，这导致每搏功增加、势能降低，从而使作功效率显著提高。因此，对功能减退心脏的变力性刺激可调节心室-动脉耦联，以优化每搏功或机械效率。
