Nakai K, Syobuzawa M, Ito C, Miyakawa T, Kato M, Kasanuki H
Department of Clinical Pathology, Iwate Medical University.
J Cardiol. 1988 Dec;18(4):1139-48.
We developed the system of high-frequency analysis of the signal-averaged body surface ECG to detect low amplitude signals in the terminal portion of the QRS. Thirty-five patients four or more weeks after transmural myocardial infarction (MI) and 30 normal volunteers were studied. All patients were in normal sinus rhythm and did not have bundle branch block. Body surface ECG recording using bipolar X, Y, and Z leads was performed in a shielded room. One lead served as the reference. The three-channel amplifier was a commercially-available ECG system. The common mode rejection ratio was 120 dB. The signal from each lead was amplified and passed through an analogue filter (NF FV 624) with a low-cut frequency of 100 Hz and a high-cut frequency of 300 Hz. Then AD conversion was performed with 12-bit accuracy, 1024 samples/sec. The filtered signals for the three leads were displayed separately for each channel and were combined into a vector magnitude, square root of X2+Y2+Z2. The percent ratio of the root mean square voltage in the last 40 msec of the QRS complex to that of the total filtered QRS (%RMS40) and the duration of the filtered QRS were automatically calculated. These parameters obtained from the three groups were compared. Signal-averaged, non-filtered and filtered body surface ECGs were recorded using 25 (5 x 5 array) anterior chest unipolar leads in 20 normal volunteers and in patients with late potential. The departure index was calculated as the voltage differences between the mean value (M) in normal persons and the value in patients (Xi) with MI using the formula (Xi-M/SDi) at intervals every four msec. The departure maps, capable of identifying the location of the MI, were made from the departure index at four msec intervals; then the late potential (LP) area maps were superimposed on the departure maps. To determine the late potential, we used the filtered ECG of X, Y, and Z leads and quantitative values (%RMS 40) obtained from a vector magnitude incorporated in these three leads. Six MI patients, four anterior and two inferior, with the late potential had low amplitude signals at the end of the filtered QRS complex. The %RMS 40 was 6.8 +/- 2.9% (p less than 0.001) in MI patients with the late potential, 2.8 +/- 8.5% (p less than 0.01) in MI patients without the late potential, and 37 +/- 11% in normal subjects.(ABSTRACT TRUNCATED AT 400 WORDS)
我们开发了信号平均体表心电图高频分析系统，以检测QRS波终末部分的低振幅信号。对35例透壁性心肌梗死（MI）四周或更长时间后的患者及30名正常志愿者进行了研究。所有患者均为正常窦性心律，且无束支传导阻滞。在屏蔽室内使用双极X、Y和Z导联进行体表心电图记录。以一导联作为参考。三通道放大器为市售心电图系统。共模抑制比为120dB。来自各导联的信号经放大后通过一个模拟滤波器（NF FV 624），其低截止频率为100Hz，高截止频率为300Hz。然后以12位精度、1024样本/秒进行模数转换。三个导联的滤波信号分别在每个通道显示，并合并为矢量大小，即X2 + Y2 + Z2的平方根。自动计算QRS波群最后40毫秒内均方根电压与整个滤波QRS波群均方根电压的百分比（%RMS40）以及滤波QRS波群的持续时间。比较了三组获得的这些参数。在20名正常志愿者和有晚电位的患者中，使用25个（5×5阵列）前胸单极导联记录了信号平均、未滤波和滤波后的体表心电图。偏离指数通过公式（Xi - M/SDi）计算，即心肌梗死患者（Xi）与正常人平均值（M）每4毫秒间隔的电压差。每隔4毫秒根据偏离指数绘制能够识别心肌梗死位置的偏离图；然后将晚电位（LP）区域图叠加在偏离图上。为了确定晚电位，我们使用了X、Y和Z导联的滤波心电图以及从这三个导联合并的矢量大小获得的定量值（%RMS 40）。6例有晚电位的心肌梗死患者，4例前壁心肌梗死，2例下壁心肌梗死，在滤波后的QRS波群终末有低振幅信号。有晚电位的心肌梗死患者%RMS 40为6.8±2.9%（p＜0.001），无晚电位的心肌梗死患者为2.8±8.5%（p＜0.01），正常受试者为37±11%。（摘要截断于400字）
