Cairo Beatrice, Pernice Riccardo, Radovanović Nikola N, Faes Luca, Porta Alberto, Platiša Mirjana M
Department of Biomedical Sciences for Health, University of Milan, 20133 Milan, Italy.
Department of Engineering, University of Palermo, Viale delle Scienze, 90128 Palermo, Italy.
Entropy (Basel). 2025 Jul 20;27(7):770. doi: 10.3390/e27070770.
The complex interplay between the cardiac and the respiratory systems, termed cardiorespiratory coupling (CRC), is a bidirectional phenomenon that can be affected by pathologies such as heart failure (HF). In the present work, the potential changes in strength of directional CRC were assessed in HF patients classified according to their cardiac rhythm via two measures of coupling based on k-nearest neighbor (KNN) estimation approaches, cross-entropy (CrossEn) and state space correspondence (SSC), applied on the heart period (HP) and respiratory (RESP) variability series, while also accounting for the complexity of the cardiac and respiratory rhythms. We tested the measures on 25 HF patients with sinus rhythm (SR, age: 58.9 ± 9.7 years; 23 males) and 41 HF patients with ventricular arrhythmia (VA, age 62.2 ± 11.0 years; 30 males). A predominant directionality of interaction from the cardiac to the respiratory rhythm was observed in both cohorts and using both methodologies, with similar statistical power, while a lower complexity for the RESP series compared to HP series was observed in the SR cohort. We conclude that CrossEn and SSC can be considered strictly related to each other when using a KNN technique for the estimation of the cross-predictability markers.
心脏与呼吸系统之间的复杂相互作用，称为心肺耦合（CRC），是一种双向现象，可能会受到心力衰竭（HF）等病理状况的影响。在本研究中，通过基于k近邻（KNN）估计方法的两种耦合度量，即交叉熵（CrossEn）和状态空间对应（SSC），应用于心动周期（HP）和呼吸（RESP）变异性序列，同时考虑心脏和呼吸节律的复杂性，评估了根据心律分类的HF患者中定向CRC强度的潜在变化。我们对25例窦性心律（SR，年龄：58.9±9.7岁；23例男性）HF患者和41例室性心律失常（VA，年龄62.2±11.0岁；30例男性）HF患者进行了这些度量测试。在两个队列中使用两种方法均观察到从心脏节律到呼吸节律的主要相互作用方向性，具有相似的统计效力，而在SR队列中观察到RESP序列的复杂性低于HP序列。我们得出结论，当使用KNN技术估计交叉可预测性标记时，CrossEn和SSC可被视为彼此密切相关。
