The importance of defining left ventricular area at risk in vivo during acute myocardial infarction: an experimental evaluation with myocardial contrast two-dimensional echocardiography.
The importance of defining left ventricular area at risk in vivo during acute myocardial infarction: an experimental evaluation with myocardial contrast two-dimensional echocardiography.
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DOI：
10.1161/01.cir.75.6.1249
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发表时间：
1987-06
期刊：
影响因子：
37.8
通讯作者：
Sanjiv Kaul;W. Glasheen;T. D. Ruddy;N. Pandian;A. Weyman;Robert D. Okada
中科院分区：
文献类型：
--
作者：
Sanjiv Kaul;W. Glasheen;T. D. Ruddy;N. Pandian;A. Weyman;Robert D. Okada
由于左心室“危险面积”是最终梗死面积的最重要决定因素，因此了解急性心肌梗死期间危险面积的大小将有助于制定治疗决策。因此，我们对四组狗进行了一系列的实验。在第一组狗（n = 15）中，我们试图确定当前评估急性心肌梗死期间左心室功能的方法是否反映了危险区域的真实大小。在2到5个连续阶段的每一个阶段，进行更近端的冠状动脉闭塞以产生更大的危险区域，直到心血管衰竭发生。在每个阶段，测量危险面积（通过心肌超声造影测量）、血流动力学变量和左心室射血分数（LVEF）。当危险区域较大（占左心室的25%至40%）时，血流动力学变量出现异常，而当危险区域中等大小（占18%）时，LVEF出现异常。当心输出量和LVEF归一化为基线值时，注意到这些变量与危险区域之间存在密切的负相关关系。相比之下，标准化平均动脉压与危险面积之间的关系较差（r = 0.42）。II组犬（n = 9）在冠状动脉闭塞后6小时内连续测量危险区域。无论最终梗死的跨壁程度如何，危险区域的大小保持不变。在9只发生梗死的狗中，有8只的危险区域的周向心内膜范围密切预测了6小时时梗死的周向心内膜范围。III组犬（n = 7）采用与II组犬相同的方案，但阻断时间为3小时。危险区域的周向心内膜范围与梗死的周向心内膜范围密切相关。IV组（n = 5）行冠状动脉次全闭塞。虽然在本组中发现了局部壁运动异常，但没有确定危险区域。我们得出结论，尽管标准化心输出量与危险面积之间存在密切的反比关系，但只有当危险面积较大（25%至40%）时，心输出量的绝对值和其他血流动力学变量才会出现异常；与血流动力学变量相比，LVEF测量可以更好地评估危险区域的大小。（摘要删节为400字）
Because the left ventricular "area at risk" is the most important determinant of ultimate infarct size, it would be useful to know the size of the area at risk during acute myocardial infarction to make therapeutic decisions. We therefore performed a series of experiments in four groups of dogs. In group I dogs (n = 15) we attempted to determine whether current methods of assessing left ventricular function during acute myocardial infarction reflect the true size of the area at risk. At each of two to five sequential stages, a more proximal coronary occlusion was performed to produce a larger area at risk until cardiovascular collapse occurred. At each stage, the area at risk (measured by myocardial contrast echocardiography), hemodynamic variables, and left ventricular ejection fraction (LVEF) were measured. Hemodynamic variables became abnormal when the area at risk was large (25% to 40% of the left ventricle), whereas LVEF became abnormal when the area at risk was of moderate size (18%). When cardiac output and LVEF were normalized to baseline values, a close inverse relationship was noted between these variables and area at risk. In contrast, there was a poor relationship between normalized mean arterial pressure and area at risk (r = .42). In group II dogs (n = 9) the area at risk was measured serially over 6 hr after coronary occlusion. The size of the area at risk remained unchanged regardless of the transmural extent of the ultimate infarct. The circumferential endocardial extent of the area at risk closely predicted the circumferential endocardial extent of the infarct at 6 hr in eight of nine dogs that developed an infarct. Group III dogs (n = 7) underwent the same protocol as group II dogs, but the duration of occlusion was 3 hr. The circumferential endocardial extent of the area at risk closely predicted the circumferential endocardial extent of the infarct. Group IV dogs (n = 5) underwent subtotal coronary occlusion. Although regional wall motion abnormalities were noted in this group, no area at risk could be defined. We conclude that although a close inverse relationship is noted between normalized cardiac output and area at risk, the absolute values for cardiac output and other hemodynamic variables become abnormal only when the area at risk is large (25% to 40%); measurement of LVEF may provide a better assessment of the size of the area at risk than hemodynamic variables.(ABSTRACT TRUNCATED AT 400 WORDS)