心室晚电位体表非创伤性检测系统

Noninvasive detecting system of ventricular late potential on bodysurface

目的：研制心室晚电位体表非创伤性检测系统．方法：采用ＸＹＺ正交导联，设计了高性能的三通道模拟信号处理器，其增益６０～８０ｄＢ，输入阻抗＞５ＭΩ，漏电流＜０．１μＡ，共模抑制比＞１２０ｄＢ，等效输入噪声＜１μＶ，频率响应０．０５～３００Ｈｚ，运用信号迭加平均技术及双线性变换（ＢＬＴ）法所设计的四阶Ｂｕｔ－ｔｅｒｗｏｒｔｈ高通滤波器分离了心室晚电位信号并克服了“振铃效应”．结果：７４例心脏病及３２例冠状动脉造影患者的检测结果表明，系统灵敏度为３７．５％，特异性为８７．５％，总符合率为７５％。结论：该系统可作为识别高危心脏病患者的辅助诊断手段．

Objective: To develop noninvasive detecting system of ventricular late potential(VLP)on bodysurface. Methods : For measuring the VLP from body surface, the authors used an XYZ lead system formedby three orthogonal bipolar electrode combinations. For VLP signal was of high frequency and low ampli-tude, we designed a high performance three-channel analog signal processor. The gain was 60～80 dB, inputimpedance>5 MΩ,leakage current<0.1 μA,CMRR>120 dB,equivalent noise<1 μV and frequency re-sponse was 0.05～300 Hz. The 300 beats in ECG signal were averaged after passing through a templaterecognition program to reject ectopic beats and grossly noisy signals.A bidirectional digital filter was devel-oped to eliminate ring effect of the fiIter. This filter was of four-order highpass butterworth design obtainedby bilinear transform(BLT) with frequency prewarping. The filtered signal for the three leads was combinedin spitial vector module,which allowed detection of VLP. Results: The results of the exami-nation in 106 patients(include 32 examined by coronary arteriography)with coronary disease showed that thesentivity, specificity and total coincident rate of this system were 37.5%, 87.5%and 75%respectivity.Con-clusions :This findings indicate that the VLP detection and analysis is an assistant, noninvasive method for i-dentifying high risk cardiac patients.