心声频谱的诊断学价值1、冠心病与正常心声频谱的线性预测分析

本文用频率响应不同的三种传声器自６９名冠心病人、３４名隐匿型冠心病人、４０名正常人引导心声信号，用线性预测法脱机分析３２６个心动周期，共提取出１５８８５０个表征心声图象的原始数据，从中经ｔ检验筛选出了在正常与隐匿型冠心病之间，及隐匿型冠心病与冠心病之间有显著差异的特征量。发现用频响低限为０．０１Ｈｚ的传声器自两组患者胸骨左缘第４肋间导出的心声，其第一心音之末至第二心音之始，以及第三心音之始至下一周期第一心音之始的两个心声段中，０－１０Ｈｚ频率区间的能量比例显著减少、２５－５００Ｈｚ频率区间的能量比例显著增多、心声频谱的最大谱峰位置与波谱形心位置基本位于可听阈以下的次声带范围内，但均显著向高频方向移动。这些规律可望用于冠心病早期诊断。

DIAGNOSTIC VALUE OF HEART SOUND SPECTRUM:1. LINEAR PREDICTION ANALYSIS OF CORONARY HEARTDISEASE AND NORMAL HEART SOUND

Three microphones with different frequency response were used in thisexperiment to lead heart sound signals from 69 cases of coronary heartdisease, 34 cases of latent coronary heart disease , and 40 normal indi-viduals. 158850 original data expressing the phonocardiogram were extra-cted off-line from 326 cardiac cycles with linear prediction analysismethod. Characteristic parameters of significant difference between gro-ups of normal and latent coronary disease, and those between groups oflatent coronary disease and coronary disease were selected by t-testfrom the original data. It was found that when the heart sounds wereled from the left sternal border in the fourth intercostal space of thetwo groups of patienst by the microphone with a lower limit offrequencyresponsc heart at 0.01 Hz, the following variations happened in the twosound segments (from the end of the first heart sound to the beginningof the second heart sound, and from the beginning of the cycle) i thethird heart sound to the beginning of the first heart sound of the nextenergy ratio of frequency between 0-10 Hz was decreased significantly,the energy ratio of frequency between 25-500Hz was increased significa-ntly, both the maximal spectral peak position and spectral centroid pos-ition moving toward the higher frequency direction, though they remai-ned basically in the subsonic area below the audiblc threshold. Thesepattcrns might be nsed in early diagnosis of coronary disease.