Evans A K, Lux R L, Burgess M J, Wyatt R F, Abildskov J A
Circ Res. 1981 Jul;49(1):197-203. doi: 10.1161/01.res.49.1.197.
This paper describes use of the Karhunen-Loeve expansion to identify and reduce temporal redundancy in electrocardiographic body surface potential maps (192 body surface leads recorded simultaneously at 1 kHz/channel for approximately 600 msec). Temporal data compression of about 20 to 1 was obtained with accurate representation of the original data. Use of separate sets of orthonormal basis functions for QRS and ST-T provided a more accurate representation than the basis derived from QRST. Combined with the spatial compression described in the preceding paper, overall map data compression of about 320 to 1 was obtained without significant loss of accuracy of representation or map appearance. With both spatial and temporal compression the 100,000 numbers which typically comprise a single cardiac complex were accurately represented by 216 coefficients. Using basis functions derived from a single cardiac complex were accurately represented by 216 coefficients. Using basis functions derived from a training set of 221 maps, the estimated average rms error of representation was 60 microV during the ST-T. For 34 test maps which were not part of the training set, measured average errors were 64 microV during the QRS and 23 microV during the ST-T. This technique provides a basis for quantification of the diagnostic content of maps and automated classification of maps.
本文描述了使用卡尔胡宁-洛伊夫展开来识别和减少体表心电图电位图中的时间冗余（以1kHz/通道的采样率同时记录192个体表导联约600毫秒的数据）。在精确表示原始数据的情况下，实现了约20比1的时间数据压缩。对QRS波群和ST-T段使用单独的正交基函数集，比从QRST导出的基函数能提供更精确的表示。结合前文所述的空间压缩，在不显著损失表示精度或图外观的情况下，获得了约320比1的总图数据压缩。通过空间和时间压缩，通常构成单个心动周期的100,000个数字可以由216个系数精确表示。使用从单个心动周期导出的基函数，由216个系数精确表示。使用从221幅图的训练集导出的基函数，在ST-T段期间表示的估计均方根误差平均为60微伏。对于不属于训练集的34幅测试图，在QRS波群期间测量的平均误差为64微伏，在ST-T段期间为23微伏。该技术为心电图电位图诊断内容的量化和图的自动分类提供了基础。
