Development of the method quantitatively to assess regional left ventricular function using high-frame-rate echocardiography.

由于许多心脏病都是局部的而非全局性的左心室异常，而且心脏病患者的左室舒张功能先于收缩功能受损，因此，如果可能的话，左心局部功能不全的测量方法应该对受累区域提供最敏感的评估。我们将高帧频二维超声心动图与数字减影图像处理相结合，制作了一种新的系统，用于显示左心室局部异常，并探讨该技术是否为缺血性心脏病患者冠状动脉病变区域的无创性评估提供了一种手段。在线提供以60帧/秒的速率获得的二维超声心动图用于数字减影分析，利用该减影分析在逐帧的基础上连续减去数字化图像。对减影图像进行分析，以确定每个受试者16个节段在舒张期早期的室壁节段向外运动的起始时间。冠脉病变节段的松弛指数(第二心音至各节段室壁运动开始的时间间隔)较正常节段显著延长(P&lt；0.01)。松弛指数延长与脑室造影局部松弛指数呈正相关(r=0.61，P<0.01)。因此，数字减影高帧频超声心动图可用于半定量评价患者左室舒张功能的局部异常。用该技术得到的从第二心音到左室壁节段性外向运动开始的时间间隔(松弛指数)，为评价冠状动脉受累区域提供了一种无创性、准确的测量方法。

Because many heart diseases are constituted regional rather than global abnormalities of the left ventricle and because left ventricular diastolic function is impaired prior to systolic function in patients with heart diseases, measures of regional left ventricular dysfunction, if possible, should provide most sensitive assessment of the involved region. We made a new system by combining high frame rate two-dimensional echocardiography with a digital subtraction image processing to visualize regional abnormalities of the left ventricle and examined whether this technique provides a measure for the noninvasive assessment of coronary involved region in patients with ischemic heart disease. Two-dimensional echocardiograms obtained at a rate of 60 frames/sec were provided on line for digital subtraction analysis with which digitized images were continuously subtracted on the frame-by-frame basis. The subtracted images were analyzed to determine the onset of the segmental outward motion of the left ventricular wall in early diastole in each of 16 segments per subject. Relaxation index, which was defined as the interval from the second heart sound to the onset of outward wall motion in each segment, was significantly prolonged in the coronary involved segments as compared to the normal segments (P<0.01). The prolongation in the relaxation index was associated with ventriculographic index of regional relaxation (r=0.61, P<0.01). Thus, digital subtraction high frame rate echocardiography may be used semi-quantitatively to assess regional abnormalities of left ventricular relaxation in patients. Time interval from the second heart sound to the onset of the segmental outward motion of the left ventricular wall (relaxation index), obtained with this technique, provides a noninvasive and accurate measure for assessing coronary involved regions.