Krams R, Soei L K, McFalls E O, Winkler Prins E A, Sassen L M, Verdouw P D
Thoraxcenter, Erasmus University Rotterdam, The Netherlands.
Am J Physiol. 1993 Dec;265(6 Pt 2):H2099-109. doi: 10.1152/ajpheart.1993.265.6.H2099.
Regional end-systolic pressure-segment length relationships (ESPSLR) were used to compare the degree of right and left ventricular stunning induced by a 10-min occlusion of the left anterior descending coronary artery and the response to subsequent atrial pacing (50 beats/min above intrinsic heart rate) without and with dobutamine (2 micrograms.kg-1.min-1) in nine anesthetized open-chest pigs. From the ESPSLR, the slope (Ees) (at 100 mmHg for the left and 25 mmHg for the right ventricle) and the total area of the pressure-length relationship (PLA) were determined. From the latter, the distribution into external work (EW) and potential energy (PE) as well as the efficiency of energy transfer (EET = EW/PLA) were calculated. In both the stunned left and right ventricular myocardium Ees and EW were reduced according to the same linear regression equations (delta Ees = 0.7 Ees,baseline - 11.4, r2 = 0.86 and delta EW = 0.4 EWbaseline + 2.3, r2 = 0.67), where Ees,baseline and EWbaseline are Ees and EW at baseline, respectively. EET of the stunned left and right ventricular segments decreased as PLA remained unchanged, due to an increase in PE. EET decreased from 0.84 +/- 0.02 to 0.71 +/- 0.03 (P < 0.05) in the stunned right ventricular segment and from 0.71 +/- 0.02 to 0.44 +/- 0.03 (P < 0.05) in the stunned left ventricular segment. Atrial pacing did not affect EET with respect to stunning levels, whereas the additional infusion of dobutamine restored Ees, EW, and PE and consequently EET to baseline values. In conclusion, the right ventricle is susceptible to stunning. During atrial pacing the EET was lower than expected from the Ees, which could, in agreement with the time-varying elastance concept, be explained by an increase in afterload (a consequence of the decrease in stroke volume). Dobutamine not only increased Ees, EW, and EET but also restored the relationship between Ees and EET in both ventricular stunned segments.
采用局部收缩末期压力-节段长度关系（ESPSLR），比较9只麻醉开胸猪在左前降支冠状动脉闭塞10分钟后左、右心室顿抑的程度，以及在无多巴酚丁胺和有多巴酚丁胺（2微克·千克⁻¹·分钟⁻¹）情况下，后续心房起搏（高于固有心率50次/分钟）时的反应。根据ESPSLR确定斜率（Ees）（左心室为100 mmHg时，右心室为25 mmHg时）以及压力-长度关系（PLA）的总面积。根据后者，计算出转化为外部功（EW）和势能（PE）的分布情况以及能量转移效率（EET = EW/PLA）。在顿抑的左、右心室心肌中，Ees和EW均按照相同的线性回归方程降低（ΔEes = 0.7Ees,基线 - 11.4，r² = 0.86；ΔEW = 0.4EW基线 + 2.3，r² = 0.67），其中Ees,基线和EW基线分别为基线时的Ees和EW。由于PE增加，PLA保持不变，顿抑的左、右心室节段的EET降低。顿抑的右心室节段的EET从0.84±0.02降至0.71±0.03（P < 0.05），顿抑的左心室节段的EET从0.71±0.02降至0.44±0.03（P < 0.05）。心房起搏对顿抑水平的EET没有影响，而额外输注多巴酚丁胺可使Ees、EW和PE恢复，从而使EET恢复至基线值。总之，右心室易发生顿抑。在心房起搏期间，EET低于根据Ees预期的值，这与时变弹性概念一致，可通过后负荷增加（每搏量减少的结果）来解释。多巴酚丁胺不仅增加了Ees、EW和EET，还恢复了两个心室顿抑节段中Ees和EET之间的关系。
