Enhancement of regional myocardial efficiency and persistence of perfusion, oxidative, and functional reserve with paired pacing of stunned myocardium.
Enhancement of regional myocardial efficiency and persistence of perfusion, oxidative, and functional reserve with paired pacing of stunned myocardium.
复制标题
通过对顿顿心肌进行配对起搏，可提高局部心肌效率以及灌注、氧化和功能储备的持续性。
DOI：
10.1161/01.cir.89.5.2290
复制
发表时间：
1994
期刊：
影响因子：
37.8
通讯作者：
Perez,JE
中科院分区：
文献类型：
--
作者：
Bergmann,SR;Weinheimer,CJ;Brown,MA;Perez,JE
心肌顿抑反映了心肌再灌注后的功能障碍，最终注定要完全恢复。大多数研究者将再灌注后休克归因于兴奋-收缩偶联的主要缺陷或肌丝对钙的敏感性改变。本研究的目的是评价心肌灌注、氧化代谢和功能之间的相互关系，以更好地描述心肌顿抑现象，定义顿抑心肌的局部效率，并描述其储备能力。（用放射性标记微球测量）、心肌耗氧量（MVO 2）（使用1- 11 C-乙酸盐进行正电子发射断层扫描定量）和心肌功能（用二维超声心动图评估）在12只麻醉的闭胸犬中进行了评价，所述犬经受15分钟的左前降支冠状动脉闭塞，随后再灌注。为了在再灌注后1小时获得测量值后评价血流、氧化和功能储备，对犬进行配对起搏（一种不改变全身血流动力学的正性肌力刺激），并重复测量。再灌注后一小时，顿抑心肌的特征是心肌灌注接近正常水平（每分钟0.57 +/- 0.13毫升/克，是偏远正常区域的81 +/- 13%），但严重运动障碍（回声评分，2.6 +/- 0.7;壁厚百分比，14 +/- 20%）。尽管收缩功能水平较低，但MVO 2平均为1.72 +/- 0.7 mumol/g/min，为远端心肌中观察到的71 +/- 27%。局部心肌效率（收缩期室壁增厚除以MVO 2）显著降低。配对起搏时，心肌灌注与远端心肌成比例增加，收缩功能改善（回声评分，1.4 ± 0.7;壁增厚百分比，30 ± 15%），局部MVO 2几乎加倍（至3.41 ± 1.82 mumol/g/min，每对测量P <0.05）。重要的是，配对起搏，局部心肌效率接近正常化，在reperfusionmyocardial.CONCLUSIONSStunned心肌的特点是近正常水平的灌注和氧消耗，尽管显着的运动障碍。心肌效率低。通过正性肌力刺激（在本研究中，成对起搏），再灌注心肌表现出相当大的灌注、氧化和功能储备，心肌效率显著改善。这些结果可能对再灌注后泵衰竭的治疗有意义。
BACKGROUNDStunned myocardium reflects postreperfusion dysfunction in myocardium that is destined to ultimately fully recover. Most investigators attribute postreperfusion stunning to a primary defect in excitation-contraction coupling or to an altered sensitivity of the myofilaments to calcium. The aim of the present study was to evaluate the interrelation between myocardial perfusion, oxidative metabolism, and function in an effort to better characterize the phenomenon of myocardial stunning, to define the regional efficiency of stunned myocardium, and to characterize its reserve capacity.METHODS AND RESULTSRegional myocardial perfusion (measured with radiolabeled microspheres), myocardial oxygen consumption (MVO2) (quantified with positron emission tomography using 1-11C-acetate), and myocardial function (assessed with two-dimensional echocardiography) were evaluated in 12 anesthetized, closed-chest dogs subjected to 15 minutes of left anterior descending coronary artery occlusion followed by reperfusion. To evaluate flow, oxidative, and functional reserve after measurements were obtained 1 hour after reperfusion, dogs were subjected to paired pacing (an inotropic stimulus that does not alter systemic hemodynamics), and measurements were repeated. One hour after reperfusion, stunned myocardium was characterized by near-normal levels of myocardial perfusion (0.57 +/- 0.13 mL/g per minute, 81 +/- 13% of that in remote, normal regions) but severe dyskinesis (echo score, 2.6 +/- 0.7; percent wall thickening, 14 +/- 20%). Despite the low level of contractile function, MVO2 averaged 1.72 +/- 0.7 mumol/g per minute, 71 +/- 27% of that observed in remote myocardium. Regional myocardial efficiency (systolic wall thickening divided by MVO2) was markedly diminished. With paired pacing, myocardial perfusion increased proportional to that in remote myocardium, systolic function improved (echo score, 1.4 +/- 0.7; percent wall thickening, 30 +/- 15%), and regional MVO2 nearly doubled (to 3.41 +/- 1.82 mumol/g per minute, P < .05 for each paired measurement). Importantly, with paired pacing, regional myocardial efficiency nearly normalized in reperfused myocardium.CONCLUSIONSStunned myocardium is characterized by near-normal levels of perfusion and oxygen consumption despite marked dyskinesis. Myocardial efficiency is poor. With inotropic stimulation (in the present study, paired pacing), reperfused myocardium demonstrated considerable perfusion, oxidative, and functional reserve and a dramatic improvement in myocardial efficiency. These results may have implications for the treatment of postreperfusion pump failure.