Search results for "Heart rate Variability"
showing 10 items of 232 documents
Disentangling cardiovascular control mechanisms during head-down tilt via joint transfer entropy and self-entropy decompositions
2015
A full decomposition of the predictive entropy (PE) of the spontaneous variations of the heart period (HP) given systolic arterial pressure (SAP) and respiration (R) is proposed. The PE of HP is decomposed into the joint transfer entropy (JTE) from SAP and R to HP and self-entropy (SE) of HP. The SE is the sum of three terms quantifying the synergistic/redundant contributions of HP and SAP, when taken individually and jointly, to SE and one term conditioned on HP and SAP denoted as the conditional SE (CSE) of HP given SAP and R. The JTE from SAP and R to HP is the sum of two terms attributable to SAP or R plus an extra term describing the redundant/synergistic contribution to the JTE. All q…
Time, frequency and information domain analysis of short-term heart rate variability before and after focal and generalized seizures in epileptic chi…
2019
OBJECTIVE In this work we explore the potential of combining standard time and frequency domain indexes with novel information measures, to characterize pre- and post-ictal heart rate variability (HRV) in epileptic children, with the aim of differentiating focal and generalized epilepsy regarding the autonomic control mechanisms. APPROACH We analyze short-term HRV in 37 children suffering from generalized or focal epilepsy, monitored 10 s, 300 s, 600 s and 1800 s both before and after seizure episodes. Nine indexes are computed in time (mean, standard deviation of normal-to-normal intervals, root mean square of the successive differences (RMSSD)), frequency (low-to-high frequency power rati…
Sympathetic tone and ventricular tachycardia
2008
Background The pathogenesis of idiopathic monomorphic ventricular tachycardia is not clear. We suppose that a lack of balance of the sympathetic system could be involved. Frequency domain analyses of the heart rate can be useful to understand autonomic system balance. Therefore we performed this evaluation on a sample of seven children affected by idiopathic monomorphic ventricular tachycardia. Methods and results We performed a Holter recording for palpitations on all the children, with an average age of 12 (range: 7-18 years). In all the patients many episodes of repeated sustained or nonsustained ventricular tachycardia were demonstrated, with an average heart rate of 170 bpm. We exclude…
A method for the time-varying nonlinear prediction of complex nonstationary biomedical signals
2009
A method to perform time-varying (TV) nonlinear prediction of biomedical signals in the presence of nonstationarity is presented in this paper. The method is based on identification of TV autoregressive models through expansion of the TV coefficients onto a set of basis functions and on k -nearest neighbor local linear approximation to perform nonlinear prediction. The approach provides reasonable nonlinear prediction even for TV deterministic chaotic signals, which has been a daunting task to date. Moreover, the method is used in conjunction with a TV surrogate method to provide statistical validation that the presence of nonlinearity is not due to nonstationarity itself. The approach is t…
The role of social processes and decision making on the psychobiological response to social stress
2018
Los humanos, a diario, se enfrentan a diversas interacciones sociales, que pueden ser interpretadas como retos o como amenazas en función del contexto y del individuo que las enfrenta. Es por ello, que el cuerpo humano acaba activando sus mecanismos fisiológicos y conductuales en función de cómo interpreta está situación. Durante toda esta interpretación los humanos deciden un patrón de conducta que les lleva a tomar un tipo de decisiones u otras para adaptarse a estas interacciones sociales. Es por ello que la toma de decisiones puede ser una variable de estudio importante a lo largo de toda una interacción social, tanto como decidimos en función de la interacción y la respuesta fisiológic…
Diferències entre sexes en la resposta cardiovascular, hormonal i psicològica a una competició: Variables moduladores i facilitadors de la victòria
2018
Competition is a social interaction where there is a confrontation between individuals or groups to achieve an objective. In our society competition is present transversally, with consequences for individuals. Therefore, competition is considered a social stressor able to elicit important psychobiological responses. From an evolutionary perspective, it has been suggested that, against stress situations, men would be more likely to fight-and-flight, while women would be more likely to tend-and-befriend strategies. Consequently, different psychobiological response to competition can be described depending on sex. A large proportion of studies on competition were based on the biosocial status …
Respuesta cardiovascular al estrés en pacientes con epilepsia farmacorresistente: datos preliminares
2021
El estrés es un factor de riesgo para las enfermedades cardiovasculares en la población general. La epilepsia se ha considerado un modelo adecuado de estrés crónico, con mayor incidencia de mortalidad cardiovascular que la población general. Este estudio proporciona datos preliminares sobre la respuesta cardiovascular ante un estresor cognitivo y una evaluación neuropsicológica en pacientes con epilepsia, explorando las relaciones entre la respuesta cardiovascular y el rendimiento cognitivo dependiendo del hemisferio responsable de la epilepsia. Treinta y cinco pacientes con epilepsia farmacorresistente, 17 con el área epileptógena(AE) en el hemisferio izquierdo (LH) y 18 con AE en el hemis…
Optimal Source Selection for Image Photoplethysmography
2016
International audience; This paper presents an optimal selection on the region of interest (ROI) and color spaces to extract photoplethysmography signals from facial videos. The study is carried out under two sections; ROI selection and color space selection. We compared five different ROI selection for different regions of the face. We also investigated three color spectrums namely additive, perceptual and orthogonal color spaces. The study experimented on the publicly available human-computer interaction (HCI) database. When evaluated on 30 subjects, the results showed that the ROI selection on the forehead and the green spectrum of the additive color space to provides higher accuracy for…
A portable system for multiple parameters monitoring: towards assessment of health conditions and stress level in the automotive field
2019
In this work, an electronic portable combo system able to synchronously acquire multiple signals, e.g. electrocardiographic (ECG), photoplethysmographic (PPG) and breathing waveforms, is presented. The realized system is also capable of showing in real time some physiological parameters which can be used for assessing health/stress status of the volunteer, such as heart rate and breathing frequency and their trends over time. Thanks to the use of non-invasive PPG probes, of batteries as power supply, and to the possibility to add in the future additional sensors to acquire other signals, the system could also be employed inside vehicles for assessing the status of the driver. Finally, the r…
Is work engagement related to healthy cardiac autonomic activity? Evidence from a field study among Finnish women workers
2012
The present study investigated whether work engagement is related to and can explain healthy cardiac autonomic activity as indicated by decreased heart rate (HR; i.e., sympathetic and parasympathetic activity) and increased high-frequency power (HFP) of heart rate variability (i.e., parasympathetic activity). A total of 30 healthy Finnish female cleaning workers underwent an ambulatory monitoring period of two nights and two regular workdays, and mean values of work period HR and HFP were utilized as dependent variables. Correlations revealed that work engagement was, as hypothesized, negatively related to HR and positively to HFP. Furthermore, in hierarchical linear regression analysis, wo…