73 research outputs found

    Attentional and emotional tasks: gender differences in heart rate variability detected by short-term detrended fluctuation analysis

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    In this study we analyzed the heart rate variability of 21 subjects, 12 females and 9 males performing a two-step task. The subjects were requested to watch a relaxing movie for 30 minutes and, in a different day, to watch a stressful movie again for 30 minutes. The electrocardiographic signal was recorded for all the duration of the sessions. The series of the beat-to-beat time intervals were analyzed by detrended fluctuation analysis. The short-term variability index clearly indicated a significant gender difference independently of the specific movie, while the long-term variability index did not reveal any significant difference of gender and task. This finding contrasts with the results of physical stimulation, which abolishes the gender differences observed in resting conditions. The discrepancy may depend on lower autonomic engagement in cognitive/affective than in physical tasks as well as on a possible different balance of the sympathetic and parasympathetic activities

    Hypnotizability dependent autonomic modulation during a low attentional task

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    Aim of the experiment was to study whether not hypnotized subjects highly (Highs) and low susceptible to hypnosis (Lows) differ in their autonomic activity during a contro lled, low attentional task eliciting relaxation

    Hypnotizability-related complexity of heart rate variability during long lasting relaxation

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    Aim of the experiment was to compare heart rate and HRV of healthy subjects with high (Highs) and low (Lows) susceptibility to hypnosis during long-lasting relaxation. HRV indexes extracted in the frequency and time domain as well as related to the complexity of the tachogram (entropy) were analyzed through repeated measures ANOVA. The results indicated a parasympathetic prevalence in Highs all over the session and a sympathetic modulation across the session in both groups reflected in the sd2 dimension of the Poincar? plot and in entropy. The possible role of the Very Low Frequency spectral component in these changes, supported by the different correlations between entropy and frequency/time related indexes of HRV, is suggeste

    Repeated mandibular extension in rat: A procedure to modulate the cerebral arteriolar tone

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    Previous data have shown both in the rat and in the human that a single mandibular extension lasting 10 min induces a significant important and prolonged reduction in blood pressure and heart rate, affecting also rat pial microcirculation by the release of endothelial factors. In the present work, we assessed whether repeated mandibular extension could further prolong these effects. We performed two mandibular extensions, the second mandibular extension being applied 10 min after the first one. The second mandibular extension produced a reduction in blood pressure and heart rate for at least 240 min. As in the case of a single mandibular extension, pial arterioles dilated persisting up to 140 min after the second extension. Spectral analysis on 30 min recordings under baseline conditions and after repetitive mandibular extensions showed that the pial arterioles dilation was associated with rhythmic diameter changes sustained by an increase in the frequency components related to endothelial, neurogenic, and myogenic activity while a single mandibular extension caused, conversely, an increase only in the endothelial activity. In conclusion, repetitive mandibular extension prolonged the effects of a single mandibular extension on blood pressure, heart rate and vasodilation and induced a modulation of different frequency components responsible of the pial arteriolar tone, in particular increasing the endothelial activity

    Subthreshold bipolar atrial stimulation affects the discharge rate of the sinus node: an animal study

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    Aim of this study was to verify whether the electrical field generated inside the right atrium by sub-threshold electrical impulses (impulses unable to induce cells activation) may condition the discharge rate of the sinus node cells. An electrophysiological study was performed on seven young farm pigs before and after denervation. After general anesthesia, pigs were stimulated with impulses delivered at constant rate by a bipolar catheter positioned inside the right atrium. The amplitude of the stimulus was set to avoid atrial capture. A 10-minute atrial stimulation was performed at a rate above and below the spontaneous heart rate, both before and after denervation. Three animals showed a conditioning of the sinus rhythm, observed as phase synchronization. The different response, or even the no response, of animals to stimulation could be due to different factors, concerning biological, pharmacological and "geometric" conditions. The important result remains that a perturbation of the sinus rhythm can be induced by a very low electrical field, as the one generated by the activity of artificial pacemakers, and it could help explaining the onset of rhythm disturbances in paced patients

    SYNCHRONIZATION INDUCED BY PACED ATRIAL SUBTHRESHOLD STIMULATION ON THE SINUS NODE ACTIVITY IN ANIMAL EXPERIMENT

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    Synchronization is the well-known phenomenon that indicates adjustment of frequencies of weakly interacting self-sustained periodic oscillators [1]. Besides the physics environment, synchronization is often encountered even in physiological systems exhibiting oscillatory behaviour. Above all others, the heart, the biological oscillator par excellence, has been object of a number of investigations. At the cellular level interesting experiments were carried out on spontaneously beating aggregates of cardiac cells from embryonic chicken heart stimulated with single impulse or impulses of different amplitudes and frequencies [2]. These experiments evidenced the interaction between stimuli and cardiac cells activity in terms of phase resetting (single stimulus) and synchronization (train of impulses). Aim of this study was to verify whether the electrical field generated inside the right atrium by subthreshold electrical impulses (impulses unable to induce cells activation) may condition the discharge rate of the sinus node cell

    Data Integration in Cardiac Surgery Health Care Institution: Experience at G. Pasquinucci Heart Hospital

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    During the last ten years the Hospital Information System (HIS) was developed at the Institute of Clinical Physiology of National Research Council (IFC-CNR), recently reorganized on clinical side into the "Gabriele Monasterio Foundation" (FGM) by joint efforts of CNR, Tuscany Region and Universities. At G.Pasquinucci Heart Hospital (GPH), currently FGM\u27s section in Massa, the HIS was adapted and extended to Cardiac Surgery and Pediatric Cardiology. Data archiving and middleware integration through HIS network, connecting GPH with head institution in Pisa, allowed to achieve full secure access to patient information from any workstation within hospital or outside. PACS was developed using Open Source DICOM utilities. Electronic Medical Record is daily used since 2005 on both inpatients and outpatients. Recently telediagnosis was set up between Balkan countries and GPH in Massa

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

    A Combined Independent Source Separation and Quality Index Optimization Method for Fetal ECG Extraction from Abdominal Maternal Leads

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    The non-invasive fetal electrocardiogram (fECG) technique has recently received considerable interest in monitoring fetal health. The aim of our paper is to propose a novel fECG algorithm based on the combination of the criteria of independent source separation and of a quality index optimization (ICAQIO-based). The algorithm was compared with two methods applying the two different criteria independently—the ICA-based and the QIO-based methods—which were previously developed by our group. All three methods were tested on the recently implemented Fetal ECG Synthetic Database (FECGSYNDB). Moreover, the performance of the algorithm was tested on real data from the PhysioNet fetal ECG Challenge 2013 Database. The proposed combined method outperformed the other two algorithms on the FECGSYNDB (ICAQIO-based: 98.78%, QIO-based: 97.77%, ICA-based: 97.61%). Significant differences were obtained in particular in the conditions when uterine contractions and maternal and fetal ectopic beats occurred. On the real data, all three methods obtained very high performances, with the QIO-based method proving slightly better than the other two (ICAQIO-based: 99.38%, QIO-based: 99.76%, ICA-based: 99.37%). The findings from this study suggest that the proposed method could potentially be applied as a novel algorithm for accurate extraction of fECG, especially in critical recording conditions

    Patient-specific seizure prediction based on heart rate variability and recurrence quantification analysis.

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    Epilepsy is often associated with modifications in autonomic nervous system, which usually precede the onset of seizures of several minutes. Thus, there is a great interest in identifying these modifications enough time in advance to prevent a dangerous effect and to intervene. In addition, these changes can be a risk factor for epileptic patients and can increase the possibility of death. Notably autonomic changes associated to seizures are highly depended of seizure type, localization and lateralization. The aim of this study was to develop a patient-specific approach to predict seizures using electrocardiogram (ECG) features. Specifically, from the RR series, both time and frequency variables and features obtained by the recurrence quantification analysis were used. The algorithm was applied in a dataset of 15 patients with 38 different types of seizures. A feature selection step, was used to identify those features that were more significant in discriminating preictal and interictal phases. A preictal interval of 15 minutes was selected. A support vector machine (SVM) classifier was then built to classify preictal and interictal phases. First, a classifier was set up to classify preictal and interictal segments of each patient and an average sensibility of 89.06% was obtained, with a number of false positive per hour (FP/h) of 0.41. Then, in those patients who had at least 3 seizures, a double-cross-validation approach was used to predict unseen seizures on the basis of a training on previous ones. The results were quite variable according to seizure type, achieving the best performance in patients with more stereotypical seizure. The results of the proposed approach show that it is feasible to predict seizure in advance, considering patient-specific, and possible seizure specific, characteristics
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