de Simone G, Devereux R B, Ganau A, Hahn R T, Saba P S, Mureddu G F, Roman M J, Howard B V
Division of Cardiology, The New York Hospital-Cornell Medical Center, New York, New York, USA.
Am J Cardiol. 1996 Oct 1;78(7):801-7. doi: 10.1016/s0002-9149(96)00425-0.
This study has been designed to improve estimation of stroke volume from linear left ventricular (LV) dimensions measured by M-mode echocardiography, in symmetrically contracting ventricles. In experimental studies, the ratio of LV epicardial long/short axes "Z" is about 1.3. We measured systolic and diastolic epicardial long and short axes by 2-dimensional echocardiography in 115 adults with widely varying LV short-axis dimensions (LV end-diastolic dimension = 3.95 to 8.3 cm). In a learning series of 23 normotensive and 27 hypertensive subjects, Z(diastole) was 1.3 +/- 0.1 and Z(systole) = 1.2 +/- 0.1, similar to findings in experimental animals. Regression equations were developed by comparing LV volumes by M-mode and 2-dimensional echocardiography. In a test series (65 subjects), LV volumes were calculated using separate regression equations for end-diastolic volume ([LV end-diastolic dimension] 4.765 - 0.288 x posterior wall thickness]) and for end-systolic volume ([LV end-systolic dimension] [4.136 - 0.288 x posterior wall thickness]). Because the term 0.288 x wall thickness was only about 8% of the first term between brackets, the average wall thickness in the learning series was substituted in the Z-volume formulas applied to the test series: end-diastolic volume = (4.5 x [LV end-diastolic dimensions]2) and end-systolic volume = (3.72 x [LV end-diastolic dimension]2). The mean relative error produced with this simplified method was 0.9%. in diastole and 1.4% in systole. Compared with Teichholz' M-mode volume method, Z-derived end-diastolic volume in the test series was equally well related to 2-dimensional volumes (both r = 0.88), with a better intercept (1.5 vs -23 ml, p <0.001) and a slope closer to the identity line (1.1 vs 1.4). Similar results were found for systolic volumes. In a second test series of 1,721 American Indian participants in the Strong Heart Study without mitral regurgitation or segmental LV wall motion abnormalities, Doppler-derived LV stroke volume (70 +/- 14 ml/beat) was similarly predicted by the Z-derived method (r = 0.65, 70 +/- 11 ml/beat) and Teichholz formulas (r = 0.64, 72 +/- 13 ml/beat), but Z-derived volumes had a regression line significantly closer to the identity line (p <0.005). Thus, LV chamber and stroke volumes can be determined from M-mode LV diameters over a wide range of LV sizes and in epidemiologic as well as clinical populations. The performance of this new method appears better than that obtained using the Teichholz formula, with a formula that is easy to handle and makes calculation of LV volumes by pocket calculator possible, even from limited echocardiographic studies.
本研究旨在改进通过M型超声心动图测量的线性左心室（LV）尺寸来估算对称收缩心室的每搏输出量。在实验研究中，左心室心外膜长轴与短轴之比“Z”约为1.3。我们通过二维超声心动图测量了115名左心室短轴尺寸差异很大（左心室舒张末期内径 = 3.95至8.3厘米）的成年人的收缩期和舒张期心外膜长轴和短轴。在一个由23名血压正常者和27名高血压患者组成的学习系列中，舒张期Z值为1.3±0.1，收缩期Z值 = 1.2±0.1，与实验动物的结果相似。通过比较M型和二维超声心动图测得的左心室容积，建立了回归方程。在一个测试系列（65名受试者）中，使用单独的回归方程计算左心室舒张末期容积（[左心室舒张末期内径]4.765 - 0.288×后壁厚度）和收缩末期容积（[左心室收缩末期内径][4.136 - 0.288×后壁厚度]）。由于0.288×壁厚项仅约为括号内第一项的8%，因此将学习系列中的平均壁厚代入应用于测试系列的Z容积公式中：舒张末期容积 = （4.5×[左心室舒张末期内径]²），收缩末期容积 = （3.72×[左心室舒张末期内径]²）。这种简化方法产生的平均相对误差在舒张期为0.9%，在收缩期为1.4%。与Teichholz的M型容积法相比，测试系列中Z衍生的舒张末期容积与二维容积的相关性同样良好（两者r = 0.88），截距更好（1.5对 -23毫升，p <0.001），斜率更接近恒等线（1.1对1.4）。收缩期容积也得到了类似结果。在第二项针对1721名无二尖瓣反流或左心室节段性壁运动异常的美国印第安人参加的强心研究测试系列中，Z衍生法（r = 0.65，70±11毫升/搏）和Teichholz公式（r = 0.64，72±13毫升/搏）对多普勒衍生的左心室每搏输出量（70±14毫升/搏）的预测相似，但Z衍生容积的回归线明显更接近恒等线（p <0.005）。因此，在广泛的左心室大小范围内，以及在流行病学和临床人群中，可根据M型左心室直径确定左心室腔容积和每搏输出量。这种新方法的性能似乎优于使用Teichholz公式获得的性能，其公式易于操作，即使通过有限的超声心动图研究，也可以使用袖珍计算器计算左心室容积。
