Correlation dimension of heartbeat intervals is reduced in conscious pigs by myocardial ischemia.
Correlation dimension of heartbeat intervals is reduced in conscious pigs by myocardial ischemia.
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DOI：
10.1161/01.res.68.4.966
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发表时间：
1991-04
影响因子：
20.1
通讯作者：
J. E. Skinner;C. Carpeggiani;C. E. Landisman;K. Fulton
中科院分区：
文献类型：
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作者：
J. E. Skinner;C. Carpeggiani;C. E. Landisman;K. Fulton
RR间期标准差（SDRR）的降低预示心肌梗死幸存者组的死亡率增加。与SDRR类似，关联维数（D2）描述了采样时间序列内的变化，但它唯一地揭示了1）历元的几何结构和2）生成器的自由度。这些独特的特征可能是比SDRR更敏感的死亡率预测因子。我们开发了一种用于估计D2的新算法（即，“point-D2”），用已知数据对其进行测试，发现它对有限数据的准确性比其他已发表的算法更高。对8只清醒的猪进行冠状动脉左前降支急性闭塞的RR间期分析显示，在缺血的第一分钟内，D2点从对照平均值和标准差2.50 +/- 0.81下降到1.58 +/- 0.64（p小于0.01），在室颤前最后一分钟降至1.07 +/- 0.18（p小于0.01）。部分闭塞（冠状动脉血流减少50-90%）引起的点D2减少仅为对照组的25-30%（p <0.01）。点D2平均值与猪呼吸性窦性心律失常的幅度相关（p <0.01），但在缺血期间，这种相关性被点D2 s和SDRR的标准差之间的相关性所取代。因为在每种情况下，平均点-D2及其标准差同时降低至1.07 +/- 0.18，这是心室颤动前几分钟独有的，并且在其他情况下从未达到这些低值，我们得出结论，点-D2可能是个体受试者死亡率的准确前瞻性预测因子。
A reduced standard deviation of RR intervals (SDRR) predicts increased mortality in groups of survivors of myocardial infarction. Like SDRR, the correlation dimension (D2) describes variation within a sampled time series, but uniquely it reveals 1) the epoch's geometric structure and 2) the degrees of freedom of the generator. These unique features may be more sensitive predictors of mortality than SDRR. We developed a new algorithm for estimating D2 (i.e., the "point-D2"), tested it with known data, and found that it had greater accuracy for finite data than other published algorithms. Analysis of RR intervals from eight conscious pigs undergoing acute occlusion of the left anterior descending coronary artery revealed a drop in the point-D2 from a control mean and standard deviation of 2.50 +/- 0.81 to 1.58 +/- 0.64 during the first minute of ischemia (p less than 0.01) and to 1.07 +/- 0.18 during the last minute preceding ventricular fibrillation (p less than 0.01). Partial occlusions (50-90% reduction of coronary blood flow) evoked point-D2 reductions only 25-30% of control (p less than 0.01). The point-D2 means were correlated between pigs with the magnitude of the respiratory sinus arrhythmia (p less than 0.01), but during ischemia this correlation was replaced by one between the standard deviation of the point-D2s and SDRRs. Because the simultaneous reduction in the mean point-D2 and its standard deviation to 1.07 +/- 0.18 occurred in every case, was unique to the few minutes preceding ventricular fibrillation, and never reached these low values during other conditions in which it was reduced, we conclude that the point-D2 may be an accurate prospective predictor of mortality within the individual subject.