Platiša Mirjana M, Bojić Tijana, Pavlović Siniša U, Radovanović Nikola N, Kalauzi Aleksandar
Faculty of Medicine, Institute of Biophysics, University of Belgrade Belgrade, Serbia.
Laboratory of Radiobiology and Molecular Genetics, Institute of Nuclear Sciences "Vinča," University of Belgrade Belgrade, Serbia.
Front Neurosci. 2016 Feb 16;10:38. doi: 10.3389/fnins.2016.00038. eCollection 2016.
Classical Poincaré plot is a standard way to measure nonlinear regulation of cardiovascular control. In our work we propose a generalized form of Poincaré plot where we track correlation between the duration of j preceding and k next RR intervals. The investigation was done in healthy subjects and patients with atrial fibrillation, by varying j,k ≤ 100. In cases where j = k, in healthy subjects the typical pattern was observed by "paths" that were substituting scatterplots and that were initiated and ended by loops of Poincaré plot points. This was not the case for atrial fibrillation patients where Poincaré plot had a simple scattered form. More, a typical matrix of Pearson's correlation coefficients, r(j,k), showed different positions of local maxima, depending on the subject's health condition. In both groups, local maxima were grouped into four clusters which probably determined specific regulatory mechanisms according to correlations between the duration of symmetric and asymmetric observed RR intervals. We quantified matrices' degrees of asymmetry and found that they were significantly different: distributed around zero in healthy, while being negative in atrial fibrillation. Also, Pearson's coefficients were higher in healthy than in atrial fibrillation or in signals with reshuffled intervals. Our hypothesis is that by this novel method we can observe heart rate regimes typical for baseline conditions and "defense reaction" in healthy subjects. These data indicate that neural control mechanisms of heart rate are operating in healthy subjects in contrast with atrial fibrillation, identifying it as the state of risk for stress-dependent pathologies. Regulatory regimes of heart rate can be further quantified and explored by the proposed novel method.
经典庞加莱图是测量心血管控制非线性调节的标准方法。在我们的研究中，我们提出了一种广义形式的庞加莱图，其中我们追踪前j个和后k个RR间期持续时间之间的相关性。通过改变j、k≤100，对健康受试者和房颤患者进行了研究。在j = k的情况下，在健康受试者中观察到典型模式，即由庞加莱图点的环路起始和结束的“路径”取代了散点图。房颤患者的情况并非如此，其庞加莱图具有简单的分散形式。此外，典型的皮尔逊相关系数矩阵r(j,k)显示出局部最大值的不同位置，这取决于受试者的健康状况。在两组中，局部最大值被分为四个簇，这可能根据观察到的对称和不对称RR间期持续时间之间的相关性确定了特定的调节机制。我们对矩阵的不对称程度进行了量化，发现它们有显著差异：在健康受试者中围绕零分布，而在房颤患者中为负。此外，健康受试者的皮尔逊系数高于房颤患者或间期重新排列的信号。我们的假设是，通过这种新方法，我们可以观察到健康受试者基线条件下典型的心率状态和“防御反应”。这些数据表明，与房颤相比，健康受试者的心率神经控制机制在起作用，将房颤识别为应激相关疾病的风险状态。心率调节机制可以通过所提出的新方法进一步量化和探索。
