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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 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...
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...
Recently it could be demonstrated that systolic and diastolic blood pressure variability (BPV) as well as segmented Poincare plot analysis (SPPA) contribute to risk stratification in patients suffering from dilated cardiomyopathy (DCM). The aim of this study was to further improve the risk stratification applying multivariate technique including QT variability (QTV). 56 low risk and 13 high risk DCM...
Complexity of R-R intervals (RR) and systolic arterial pressure (SAP) variability were computed to detect the aging process influence over cardiovascular control in resting supine (REST) and standing position (STAND). One hundred healthy subjects were divided into five groups (n=20 for each), according to age: 21–30; 31–40; 41–50; 51–60; 61–70. The RR and SAP series were recorded for 15 minutes at...
The analysis of symbolic dynamics applied to the RR interval series is able to retrieve information about dynamical properties. Three different strategies of symbolic transformations were investigated: (1) symbolization based on the deviation from the average, (2) symbolization based on equidistant levels between the minimum and maximum, (3) binary symbolization of the first derivative. Each method...
Advanced resting ECG parameters such the mean vector angle between the QRS complex and T wave (spatial QRS-T angle), and the QT interval variability index (QTVI) have important diagnostic and prognostic utility, but their reliability and reproducibility (R&R) are not well characterized. We hypothesized that the spatial QRS-T angle would have relatively higher R&R than parameters such as QTVI...
The level of sedation in patients undergoing medical procedures evolves continuously since the effect of the anesthetic and analgesic agents is counteracted by noxious stimuli. The monitors of depth of anesthesia, based on the analysis of the electroencephalogram (EEG), have been progressively introduced into the daily practice to provide additional information about the state of the patient. However,...
Scaling properties of return intervals of heart rate variability for different disease (cardiac arrest and aortic valve stenosis, 73 pts) are assessed. The scaling exponent is found to depend on the level of risk but its properties are disease dependent. Preliminary results for aortic valve stenosis show that a way to predict the risk of sudden death after surgery may be found.
Dynamical aspects of cardiovascular regulation are revealed in the head-up tilt test by the properties of the distribution of time-increments between subsequent heart contractions. The Generalized Porta Index (GPI) is introduced and then calculated for the pooled probability density functions. GPI reveals marked differences between the dynamical response to the tilt test of healthy subjects prone...
Heart rhythm abnormalities such as atrial fibrillation (AF), atrial or ventricular ectopy and reduced heart rate variability (HRV) are associated with an increased risk of mortality. These altered dynamical properties might be useful in estimating the risk of death. In this work, a mortality risk stratification analysis was performed on the University of Virginia (UVa) Holter database using 2 entropy-based...
We developed Physiolyze, a Galaxy-based web framework to process Heart Rate Variability (HRV) data. Our framework includes the pyHRV library, an up-to-date collection of Python methods to calculate HRV indexes. Physiolyze can be used both through a web interface and a web service component for a fast and configurable embedding of HRV analysis in complex processing pipelines. The framework also provides...
Heart rate variability (HRV) decrease has been described in patients with obstructive sleep apnea syndrome (OSAS). Nevertheless, time and frequency domain methods commonly used for HRV analysis are considered not completely reliable in case of respiratory and arrhythmic disorders. On the contrary, the nonlinear approach may supply powerful and promising tools to give a better insight of the autonomic...
Sudden cardiac death (SCD) is the most dreadful complication of many cardiac diseases. No study has already investigated the myocardial temporal dispersion indexes as possible tools in stratifying the overall cardiovascular mortality in patients with coronary risk factors and preserved left ventricular systolic function. Method — We retrospectively compared the short-term (5-minutes) heart rate variability...
The aim of this study is to evaluate the relationship between baroreflex function and pain in women with fibromyalgia syndrome (FMS). Ten women with clinical diagnosis of FMS took part in the research. The ECG and blood pressure were continuously recorded on a beat to beat basis in supine and orthostatic postures. Coherence between SAP and RR variability (K2SAP-RR) and baroreflex function (index α)...
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