Complex dynamics underlying the human electrocardiogram

Ravelli, Flavia; Antolini, R.

doi:10.1007/bf00201802

Cited by 71 publications

(28 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This suggests that the nonlinear method can provide additional informative data for detecting epileptogenic foci. Moreover, the concordance of results between the nonlinear method and SPECT confirms the hypothesis that a loss of complexity appears when biological systems become functionally impaired [35]. …”

Section: Discussionsupporting

confidence: 56%

“…(2) EEG recorded during epileptic seizures showed nonlinear characteristics [15, 26, 33, 34]. (3) Some studies revealed that loss of complexity was related to functional impairment of the brain system [35, 36, 37], and decreased dimensional complexities of interictal EEG were observed in epileptic patients [27, 38, 39]. (4) Dimensional complexities of interictal EEG signals were higher than those of ictal EEG but lower than those of normal EEG [27].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Relationship of Nonlinear Analysis, MRI and SPECT in the Lateralization of Temporal Lobe Epilepsy

Jing

Takigawa²,

Benasich³

2002

Eur Neurol

View full text Add to dashboard Cite

Objectives: The purpose of this study was to investigate the correlation of lateralization by nonlinear analysis, magnetic resonance imaging (MRI) and interictal single-photon emission computed tomography (SPECT) in patients with temporal lobe epilepsy. Methods: Twenty-three patients (7 males, 16 females) were examined by MRI, interictal SPECT and EEG. Nonlinear dynamic properties of neuronal networks were estimated by calculating correlation dimensions on interictal EEG signals and corresponding surrogate data. Lateralization was detected based on the criteria introduced in this study. Concordance rates of the results among the three methods were compared. Results: Epileptogenic foci were shown in the temporal areas in 21 patients using the nonlinear method (8 left, 2 right, 11 both), while 20 patients showed abnormalities in temporal lobes on MR images (13 left, 5 right, 2 both). Low cerebral blood flows of the temporal lobes were detected in all patients (11 left, 8 right, 4 both). Completely concordant lateralization was observed in 8 patients (35%) for the nonlinear method and MRI, in 9 patients (39%) for the nonlinear method and SPECT, and in 10 patients (43%) for MRI and SPECT. There were no significant differences among the concordance rates for these different methods. Conclusions: Our results revealed that correlation dimension is useful for differentiating dynamic properties of neuronal networks in the interictal state, and can provide informative data for localizing epileptogenic foci in epileptic patients. Therefore, the present nonlinear method is recommended for use with patients during presurgical evaluation.

show abstract

Section: Discussionsupporting

confidence: 56%

Section: Methodsmentioning

confidence: 99%

Relationship of Nonlinear Analysis, MRI and SPECT in the Lateralization of Temporal Lobe Epilepsy

Jing

Takigawa²,

Benasich³

2002

Eur Neurol

View full text Add to dashboard Cite

show abstract

“…The provocative cardiac chaos-control study by Garfinkel et al (15), combined with data suggesting that fibrillation is chaotic (43,44), sparked interest in nonlinear-dynamical control of fibrillation. However, other work has questioned the chaotic fibrillation hypothesis (45,46).…”

Section: Discussionmentioning

confidence: 99%

Nonlinear-dynamical arrhythmia control in humans

Christini

Steín²,

Markowitz³

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

114

View full text Add to dashboard Cite

Nonlinear-dynamical control techniques, also known as chaos control, have been used with great success to control a wide range of physical systems. Such techniques have been used to control the behavior of in vitro excitable biological tissue, suggesting their potential for clinical utility. However, the feasibility of using such techniques to control physiological processes has not been demonstrated in humans. Here we show that nonlinear-dynamical control can modulate human cardiac electrophysiological dynamics by rapidly stabilizing an unstable target rhythm. Specifically, in 52͞54 control attempts in five patients, we successfully terminated pacing-induced period-2 atrioventricular-nodal conduction alternans by stabilizing the underlying unstable steady-state conduction. This proof-of-concept demonstration shows that nonlinear-dynamical control techniques are clinically feasible and provides a foundation for developing such techniques for more complex forms of clinical arrhythmia.I ncreasingly, it is recognized that many cardiac arrhythmias can be characterized on the basis of the physical principles of nonlinear dynamics (1, 2). A nonlinear-dynamical system is one that changes with time and cannot be broken down into a linear sum of its individual components. For certain nonlinear systems, known as chaotic systems, behavior is aperiodic and long-term prediction is impossible, even though the dynamics are entirely deterministic (i.e., the dynamics of the system are completely determined from known inputs and the previous state of the system, with no influence from random inputs). Importantly, such determinism actually can be exploited to control the dynamics of a chaotic system. To this end, a variety of nonlineardynamical control techniques, also known as chaos control, ‡ have been developed (3, 4) and applied successfully to a wide range of physical systems (5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Such techniques are modelindependent, i.e., they require no a priori knowledge of the underlying equations of a system and are therefore appropriate for systems that are essentially ''black boxes.''The success of nonlinear-dynamical control techniques in stabilizing physical systems, together with the facts that many physiological systems are nonlinear (e.g., the cardiac conduction system, because of its numerous complex nonlinear component interactions) and lack the detailed analytical system models required for model-based control techniques, have fostered widespread interest in applying these model-independent techniques to biological dynamical systems (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26). In a pioneering application, Garfinkel et al. (15) stabilized drug-induced irregular cardiac rhythms by means of dynamically timed electrical stimulation in an in vitro rabbit ventricular-tissue preparation. That work was an important demonstration that the physical principles of nonlinear-dynamical control could be extended into the realm of cardiac dynamics. Although extension of that work to the control of fibrill...

show abstract

“…Chaotic phenomena have been observed in reaction-diffusion systems in chemistry [2], fundamental models of classical mechanics such as pendulum with periodic excitations [3], mathematical models describing fluid dynamics [4] and hydrodynamics [5]. Unique features of chaotic signals have been registered in brain activity [6] or electrocardiogram [7] data. The emergence of a population of different species in biology [8], commodity exchange in economy [9] and time-dependent models of many ecological situations [10] are other examples of dynamical systems that are subject to chaotic dynamics.…”

Section: Introductionmentioning

confidence: 99%

New Chaotic Dynamical System with a Conic-Shaped Equilibrium Located on the Plane Structure

Petržela

Götthans

2017

Applied Sciences

View full text Add to dashboard Cite

Featured Application: Theoretical foundations provided in this contribution demonstrate that the existence of chaos is not bound to mathematical models and electronic circuits with singular equilibrium points. The practical part of this work proves that a structurally stable hidden chaotic attractor can be both excited and experimentally observed in a lumped electronic circuit; that is, it can be measured by a digital oscilloscope.Abstract: This paper presents a new autonomous deterministic dynamical system with equilibrium degenerated into a plane-oriented hyperbolic geometrical structure. It is demonstrated via numerical analysis and laboratory experiments that the discovered system has both a structurally stable strange attractor and experimentally measurable chaotic behavior. It is shown that the evolution of complex dynamics can be associated with a single parameter of a mathematical model and, due to one-to-one correspondence, to a single circuit parameter. Two-dimensional high resolution plots of the largest Lyapunov exponent and basins of attraction expressed in terms of final state energy are calculated and put into the context of the discovered third-order mathematical model and real chaotic oscillator. Both voltage-and current-mode analog chaotic oscillators are presented and verified by visualization of the typical chaotic attractor in a different fashion.

show abstract

Complex dynamics underlying the human electrocardiogram

Cited by 71 publications

References 29 publications

Relationship of Nonlinear Analysis, MRI and SPECT in the Lateralization of Temporal Lobe Epilepsy

Relationship of Nonlinear Analysis, MRI and SPECT in the Lateralization of Temporal Lobe Epilepsy

Nonlinear-dynamical arrhythmia control in humans

New Chaotic Dynamical System with a Conic-Shaped Equilibrium Located on the Plane Structure

Contact Info

Product

Resources

About