Kondo H, Masuyama T, Ishihara K, Mano T, Yamamoto K, Naito J, Nagano R, Kishimoto S, Tanouchi J, Hori M
First Department of Medicine, Osaka University School of Medicine, Suita, Japan.
Circulation. 1995 Jan 15;91(2):304-12. doi: 10.1161/01.cir.91.2.304.
Because left ventricular (LV) diastolic function is impaired before systolic function in patients with ischemic heart disease and because ischemic heart disease is constituted of regional rather than global abnormalities of the left ventricle, measures of LV regional diastolic dysfunction, if possible, should provide the most sensitive assessment of the coronary involved region. The objectives of this study are to clarify whether high-frame-rate two-dimensional echocardiography, combined with digital subtraction image processing, may be used to visualize regional LV relaxation abnormalities in patients with ischemic heart disease and to clarify whether this technique provides a measure for the noninvasive assessment of the coronary involved region.
In 30 normal subjects and 59 patients with ischemic heart disease, two-dimensional echocardiograms obtained at a rate of 60 frames per second were provided on line for digital subtraction analysis, with which digitized images were continuously subtracted on a frame-by-frame basis. The subtracted images were analyzed to determine the onset of the segmental outward motion of the LV wall in early diastole in each of 16 segments per subject. Regional relaxation index, defined as the interval from the second heart sound to the onset of outward wall motion, was significantly prolonged in the coronary involved segments compared with the normal segments (36.3 +/- 18.0 versus 101.2 +/- 34.0 ms, P < .01). The prolongation in the regional relaxation index was observed even in the coronary involved segments without reduction in systolic wall motion. When a cutoff level of 50.0 ms was used, coronary involved segments could be distinguished from normal or border segments with a sensitivity of 92% and a specificity of 81%.
Digital subtraction high-frame-rate echocardiography may be used to visualize regional LV relaxation abnormalities in patients with ischemic heart disease. The time interval from the second heart sound to the onset of the segmental outward motion of the LV wall (regional relaxation index) obtained with this technique provides a noninvasive and accurate measure for assessing coronary involved regions.
由于在缺血性心脏病患者中，左心室（LV）舒张功能在收缩功能受损之前就已受到影响，并且由于缺血性心脏病是由左心室的局部而非整体异常构成，因此，如果可能的话，左心室局部舒张功能障碍的测量方法应能对冠状动脉受累区域提供最敏感的评估。本研究的目的是阐明高帧率二维超声心动图结合数字减法图像处理是否可用于观察缺血性心脏病患者左心室局部舒张异常，以及阐明该技术是否为冠状动脉受累区域的无创评估提供一种方法。
对30名正常受试者和59名缺血性心脏病患者，以每秒60帧的速率获取二维超声心动图并进行在线数字减法分析，在此基础上逐帧连续减去数字化图像。对减去后的图像进行分析，以确定每个受试者16个节段中左心室壁在舒张早期节段向外运动的起始点。区域舒张指数定义为从第二心音到壁向外运动起始点的时间间隔，与正常节段相比，冠状动脉受累节段的该指数显著延长（36.3±18.0对101.2±34.0毫秒，P<.01）。即使在冠状动脉受累节段中未出现收缩期壁运动减弱的情况下，也观察到了区域舒张指数的延长。当使用50.0毫秒的截断值时，冠状动脉受累节段与正常或边界节段的区分敏感度为92%，特异度为81%。
数字减法高帧率超声心动图可用于观察缺血性心脏病患者左心室局部舒张异常。用该技术获得的从第二心音到左心室壁节段向外运动起始点的时间间隔（区域舒张指数）为评估冠状动脉受累区域提供了一种无创且准确的方法。
