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Early detection of cardiac autonomic neuropathy (CAN) is vital to provide timely health care. There are a variety of measures that can be considered for detection of CAN from the heart beat signal, which should provide a relatively noninvasive test. In this work we consider the use of two measures based on the RR interval — the standard deviation and the Renyi Entropy. We find that caution is indicated...
Early identification of cardiac autonomic neuropathy (CAN) leads to better treatment outcomes. Heart rate variability (HRV) analysis allows identification of CAN but is sensitive to the length of recording and the presence of artifacts and ectopics, requiring preprocessing and consideration of length of recording. RR intervals from 10-second and 5-minute ECG recordings from patients with no CAN, early...
We studied the networks of Granger causality (GC) between the time series of cardiac vagal autonomic activity and brain wave activities, measured respectively as the normalized high frequency (HF) component of heart rate variability and EEG power in the δ, θ, α, σ, β bands, computed in 10 healthy subjects during sleep. GC analysis was performed by vector autoregressive modeling, and significance of...
The study compares permutation and coarse-grained entropy approaches for the assessment of short-term complexity of the cardiovascular control from heart period (HP) variability recordings. Approaches were applied to simulations and to HP variability series recorded during complete vagal blockade obtained via administration of a high dose of atropine (AT). Differences between the estimated complexity...
The developing coordination in the fetal nervous system can be evaluated from heart rate and movement patterns. According to universal principles of development and self-organization heart rate indices of fluctuation amplitude, complexity, and pattern formation constitute a fetal autonomic brain age score (fABAS). The formation of fetal body movement related heart rate accelerations represents a particular...
Wrist worn activity monitors are becoming increasingly popular and could be greatly enhanced by the inclusion of additional physiological monitors. This paper investigates integrating wrist based electrocardiography into such devices. Results show that when no motion is present techniques and algorithms developed for traditional chest ECG can be directly re-applied to the wrist with a valid analysis...
The aim of this study was to characterize the changes in cardiovascular dynamics as a result of orthostatic and mental stress and their combination by linear and information domain analysis of heart rate and blood pressure oscillations. We recorded beat-to-beat RR intervals and systolic blood pressure values in 16 volunteers during mental arithmetics task and head-up tilt test and their simultaneous...
The aim of our research was to verify if the time irreversibility of heart rate oscillations exists even in the newborns. Multiscale irreversibility indices (Porta's index P%, Guzik index G% and Ehlers index E) of the heart rate signals were computed in 20 healthy neonates. The presence of irreversibility and its origin in system nonlinearity was assessed by surrogate data analysis. The results were...
The mechanisms underlying the onset of postoperative atrial fibrillation (POAF) are still poorly understood. Enhanced atrial automaticity and alterations in autonomic tone following surgery have been suggested as critical predisposing factors. This paper proposes an unified framework for the combined analysis of ectopic activity and autonomic function preceding POAF. Atrial intervals series were automatically...
Cardiotocography (CTG) is the most frequently used electronic fetal monitoring technique, both in the antepartum and intrapartum periods. A few systems for computer analysis of CTG tracings have been developed, but there is still a large room for improvement in their capacity to diagnose fetal hypoxia/acidosis. Research on fetal heart rate (FHR) analysis has shown that several factors are not commonly...
Frailty has been described as a clinical state of vulnerability to stress, consequence from decline of resilience and physiological reserves and progressive decline on ability of homeostasis maintenance. The aim of this study was to evaluate the complexity of R-R intervals (RR) in resting supine (REST) and standing (STAND) position in 3 groups: frail, pre-frail and non-frail. Eighty older people (60–94...
In this study, we assessed the information dynamics of respiration and heart rate variability during mental stress testing by means of the cross-entropy, a measure of cardiorespiratory coupling, and the self-entropy of the tachogram conditioned to the knowledge of respiration. Although stress is related to a reduction in vagal activity, no difference in cardiorespiratory coupling was found when 5...
Complexity measures have been widely used to characterize the nonlinear nature of cardiovascular control and heartbeat dynamics. Current approaches associate these measures to finite single values within an observation window, thus not being able to characterize instantaneous system dynamics. In this study, we introduce the definition of novel measures of entropy based on the inhomogeneous point-process...
In recent years, it became of great importance in different fields of sciences to understand how regulatory systems interact with each other (directly or indirectly, causally or non-causally). Therefore, especially in the medical field several methods for analyzing couplings in biological systems have been developed to quantify the physiological regulatory mechanisms especially of the cardiovascular...
Nowadays, standalone dry electrode-sensors allow for acquiring ECGs with a signal quality similar to those of standard ECG recorders. Moreover, standalone electrode-sensors are much easier to connect than the usual electrodes and do not require a specific electronic box for the recorder (the measured biopotentials are recorded directly in the electrode-sensors). This results in very high overall integration,...
In 51 healthy fetuses at term, we calculated fetal heart rate variability (HRV) obtained using a fetal ECG monitor which automatically determined RR interval durations. We compared the values of various HRV measures from different domains to those obtained from high quality fetal magnetocardiographic acquisitions in a similar subject group. The comparison showed significant differences in all domains,...
It is well known that epilepsy has a profound effect on the autonomic nervous system, especially on the autonomic control of heart rate and respiration. This effect has been widely studied during seizure activity, but less attention has been given to interictal (i.e. seizure-free) activity. The studies that have been done on the latter, showed that heart rate and respiration can be affected individually,...
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