Heart Rhythm Analysis Using Nonlinear Oscillators with Duffing-Type Connections

Fonkou, Rodrigue F.; Savi, Marcelo A.

doi:10.3390/fractalfract7080592

Cited by 3 publications

(1 citation statement)

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“…Analysis of cardiac dynamics is important for understanding and interpreting physiological behaviour [1][2][3]. Previous work has shown that the heart can be modelled as a combination of nodes called the cardiac conduction system [4][5][6][7][8]. Figure 1 illustrates how the cardiac conduction system works.…”

Section: Introductionmentioning

confidence: 99%

On the heart rhythm analysis using a nonlinear dynamics perspective: analytical study and electronic simulation

Fonkou,

Kengne,

Wamba

et al. 2024

Phys. Scr.

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Biological systems are highly complex, so understanding them requires extensive analysis. Cardiac rhythms are one such analysis. These rhythms are linked to a complex dynamic system defined on the basis of the electrical activity of cardiac cells. This electrical activity is essential to human physiology, defining numerous behaviours that include normal or pathological rhythms, generally measured by the electrocardiogram (ECG). This article presents a mathematical model to describe the electrical activity of the heart, using a nonlinear dynamics perspective. The stability analysis of this model in its autonomous state, uni-directionally coupled, shows a very rich dynamical behaviour characterized by periodical regions of stability and unstability. The model studied makes it possible to construct synthetic ECGs. These ECGs demonstrate a variety of responses, including normal and pathological rhythms: ventricular flutter, ventricular fibrillation, ventricular tachycardia and ventricular extrasystole. A quantitative analysis of the model is also carried out using bifurcation diagrams and the corresponding maximum Lyapunov exponents. In addition, variations in sinus rhythm are described by a time-dependent frequency (a dynamic variable varying in a disordered manner or following a given law), representing transient disturbances. This type of situation can represent transitions between different pathological behaviours or between normal and pathological physiologies. In this respect, the perspective of nonlinear dynamics is used to describe cardiac rhythms, which makes it possible to represent normal or pathological behaviours. An electronic simulation performed with the OrCAD-Pspice software for a real implementation of the cardiac system is carried out. The results obtained are in agreement with those obtained numerically.

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Section: Introductionmentioning

confidence: 99%

On the heart rhythm analysis using a nonlinear dynamics perspective: analytical study and electronic simulation

Fonkou,

Kengne,

Wamba

et al. 2024

Phys. Scr.

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Sustainable, Wearable, and Eco‐Friendly Electronic Textiles

Dulal,

Modha,

Liu

et al. 2024

Energy & Environ Materials

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Wearable electronic textiles (e‐textiles) with embedded electronics offer promising solutions for unobtrusive, real‐time health monitoring, enhancing healthcare efficiency. However, their adoption is limited by performance and sustainability challenges in materials, manufacturing, and recycling. This study introduces a sustainable paradigm for the fabrication of fully inkjet‐printed Smart, Wearable, and Eco‐friendly Electronic Textiles (SWEET) with the first comprehensive assessments of the biodegradability and life cycle assessment (LCA). SWEET addresses existing limitations, enabling concurrent and continuous monitoring of human physiology, including skin surface temperature (at temperature coefficient of resistance, TCR value of ~−4.4% °C−1) and heart rate (~74 beats per minute, bpm) separately and simultaneously like the industry gold standard, using consistent, versatile, and highly efficient inkjet‐printed graphene and Poly (3,4‐ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS)‐based wearable e‐textiles. Demonstrations with a wearable garment on five human participants confirm the system's capability to monitor their electrocardiogram (ECG) signals and skin temperature. Such sustainable and biodegradable e‐textiles decompose by ~48% in weight and lost ~98% strength over 4 months. Life cycle assessment (LCA) reveals that the graphene‐based electrode has the lowest climate change impact of ~0.037 kg CO2 eq, 40 times lower than reference electrodes. This approach addresses material and manufacturing challenges, while aligning with environmental responsibility, marking a significant leap forward in sustainable e‐textile technology for personalized healthcare management.

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Adaptive control of cardiac rhythms

da Silva Lima,

Amorim Savi,

Moreira Bessa

2024

Sci Rep

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Cardiac rhythms are related to heart electrical activity, being the essential aspect of the cardiovascular physiology. Usually, these rhythms are represented by electrocardiograms (ECGs) that are useful to detect cardiac pathologies. Essentially, the heart activity starts in the sinoatrial node (SA) node, the natural pacemaker, propagating to the atrioventricular node (AV), and finally reaching the His-Purkinje complex (HP). This paper investigates the control of cardiac rhythms in order to induce normal rhythms from pathological responses. A mathematical model that presents close agreement with experimental measurements is employed to represent the heart functioning. The adopted model comprises a network of three nonlinear oscillators that represent each one of the cardiac nodes, connected by delayed couplings. The pathological behavior is induced by an external stimulus in the SA node. An adaptive controller is proposed acting in the SA node considering an strategy based on the signal obtained by the natural pacemaker and its regularization. The incorporation of adaptive compensation in a Lyapunov-based control scheme allows the compensation for the unknown dynamics. The controller ability to deal with interpatient variability is evaluated by assuming that the heart model is not available to the controller design, being used only in the simulator to assess the control performance. Results show that the adaptive term can reduce the control effort by around 3% while reducing the tracking error by 20%, when compared to the conventional feedback approach. Additionally, the controller can avoid abnormal rhythms, turning the ECG closer to the expected normal behavior and preventing critical cardiac responses. Therefore, this work demonstrates that an adaptive controller can be used to regulate the ECG signal without prior information about the system and disregarding inter- and intrapatient variability.

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Heart Rhythm Analysis Using Nonlinear Oscillators with Duffing-Type Connections

Cited by 3 publications

References 59 publications

On the heart rhythm analysis using a nonlinear dynamics perspective: analytical study and electronic simulation

On the heart rhythm analysis using a nonlinear dynamics perspective: analytical study and electronic simulation

Sustainable, Wearable, and Eco‐Friendly Electronic Textiles

Adaptive control of cardiac rhythms

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