McClements B M, Weyman A E, Newell J B, Picard M H
Cardiac Ultrasound Laboratory, Cardiology Division, Massachusetts General Hospital, Department of Medicine, Harvard Medical School, Boston 02114, USA.
Am Heart J. 2000 Aug;140(2):284-9. doi: 10.1067/mhj.2000.107543.
This study was performed to determine if factors other than the size of regional dysfunction influence the global left ventricular ejection fraction after acute myocardial infarction.
Left ventricular ejection fraction is an important prognostic variable after acute myocardial infarction. Although infarct size is known to affect the subsequent global left ventricular ejection fraction, it remains unclear whether other factors such as site or severity of the wall motion abnormality influence the ejection fraction after acute myocardial infarction.
Sixty-nine consecutive patients (mean age 61 +/- 14 years, 46 [67%] male) who did not receive thrombolytic therapy or undergo early revascularization were studied by echocardiography 1 week after Q-wave myocardial infarction. The absolute size of the region of abnormal wall motion (AWM) and the percentage of the endocardium involved (%AWM) were quantitated along with the wall motion score. A severity index was then derived as the mean wall motion score within the region of AWM. Site of myocardial infarction was classified as either anterior or inferior from the endocardial map. Left ventricular ejection fraction was measured by Simpson's method with 2 apical views.
Twenty-nine (42%) patients had anterior and 40 had inferior myocardial infarction. The mean left ventricular ejection fraction was significantly lower in anterior than in inferior myocardial infarction (44.8% +/- 11.5% vs 53% +/- 8.6%; P =. 001). The mean %AWM was greater in anterior than in inferior myocardial infarction (32.1 +/- 15.5 vs 22.4 +/- 14.1; P =.01). The mean wall motion score was greater in anterior than in inferior myocardial infarction (9.8 +/- 6.4 vs 6.4 +/- 4.4; P =.01). The mean severity index did not differ by site. Multiple regression analysis demonstrated that, in descending order of importance, %AWM, extent of apical involvement, and site of myocardial infarction were independent determinants of global left ventricular ejection fraction.
For myocardial infarctions of similar size, left ventricular ejection fraction is lower when apical involvement is extensive and the site of infarction is anterior. This site-dependent difference may be related to characteristics specific to the apex.
本研究旨在确定除局部功能障碍大小之外的因素是否会影响急性心肌梗死后的左心室整体射血分数。
左心室射血分数是急性心肌梗死后一个重要的预后变量。虽然已知梗死面积会影响随后的左心室整体射血分数，但壁运动异常的部位或严重程度等其他因素是否会影响急性心肌梗死后的射血分数仍不清楚。
对69例连续的患者（平均年龄61±14岁，46例[67%]为男性）进行研究，这些患者未接受溶栓治疗或早期血运重建，在Q波心肌梗死后1周通过超声心动图进行检查。对壁运动异常（AWM）区域的绝对大小和受累心内膜的百分比（%AWM）以及壁运动评分进行定量分析。然后得出一个严重程度指数，即AWM区域内的平均壁运动评分。根据心内膜图将心肌梗死部位分为前壁或下壁。采用双平面Simpson法测量左心室射血分数。
29例（42%）患者为前壁心肌梗死，40例为下壁心肌梗死。前壁心肌梗死患者的平均左心室射血分数显著低于下壁心肌梗死患者（44.8%±11.5%对53%±8.6%；P = 0.001）。前壁心肌梗死患者的平均%AWM高于下壁心肌梗死患者（32.1±15.5对22.4±14.1；P = 0.01）。前壁心肌梗死患者的平均壁运动评分高于下壁心肌梗死患者（9.8±6.4对6.4±4.4；P = 0.01）。平均严重程度指数在不同部位之间无差异。多元回归分析表明，按重要性降序排列，%AWM、心尖受累程度和心肌梗死部位是左心室整体射血分数的独立决定因素。
对于大小相似的心肌梗死，当心尖受累广泛且梗死部位为前壁时，左心室射血分数较低。这种部位依赖性差异可能与心尖的特定特征有关。
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