Analysis of the ST-T complex of the electrocardiogram using the Karhunen-Loeve transform:: adaptive monitoring and alternans detection
Analysis of the ST-T complex of the electrocardiogram using the Karhunen-Loeve transform:: adaptive monitoring and alternans detection
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DOI：
10.1007/bf02513285
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发表时间：
1999-03-01
影响因子：
3.2
通讯作者：
Mark, RG
中科院分区：
文献类型：
--
作者：
Laguna, P;Moody, GB;Mark, RG
Karhunen-Loeve变换（KLT）被应用于研究心室复极周期反映在ST-T复合的表面心电图。KLT系数提供了定量ST-T形状的灵敏手段。使用ST-T复合体的训练集来导出允许使用四个KLT系数表示90%的信号能量的KLT基向量集。由于截断的KLT展开倾向于支持信号的表示而不是任何加性噪声，因此从连续ST-T复合波获得的KLT系数的时间序列比离散参数（例如ST水平或其他局部指数）更适合于表示中期变化（例如缺血性变化）和短期变化（例如ST-T交替）。对于缺血性变化的分析，描述了可用于估计KLT系数的自适应滤波器，其产生10 dB（u = 0.1）的信噪比增加，收敛时间约为三拍。未滤波的KLT系数序列的拍频谱用于检测ST-T交替。这些方法都说明了从欧洲ST-T数据库的例子。约20%的记录显示缺血性ST-T改变的准周期性发作，另外20%的记录显示重复的但不明显的ST-T改变的周期性发作模式。约5%的缺血发作与ST-T交替有关。
The Karhunen-Loeve transform (KLT) is applied to study the ventricular repolarisation period as reflected in the ST-T complex of the surface ECG. The KLT coefficients provide a sensitive means of quantitating ST-T shapes. A training set of ST-T complexes is used to derive a set of KLT basis vectors that permits representation of 90% of the signal energy using four KLT coefficients. As a truncated KLT expansion tends to favor representation of the signal over any additive noise, a time series of KLT coefficients obtained from successive ST-T complexes is better suited for representation of both medium-term variations (such as ischemic changes) and short-term variations (such as ST-T alternans) than discrete parameters such as the ST level or other local indices. For analysis of ischemic changes, an adaptive filter is described that can be used to estimate the KLT coefficient, yielding an increase in the signal-to-noise ratio of 10 dB (u = 0.1), with a convergence time of about three beats. A beat spectrum of the unfiltered KLT coefficient series is used for detection of ST-T alterans. These methods are illustrated with examples from the European ST-T Database. About 20% of records revealed quasi-periodic salves of ischemic ST-T change episodes and another 20% exhibit repetitive, but not clearly periodic patterns of ST-T change episodes. About 5% of ischemic episodes were associated with ST-T alternans.