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210 results on '"Menicucci D"'

1. A Virtual Reality-Based Setting to Investigate How Environments and Emotionally-Laden Stimuli Interact and Compete for Accessing Consciousness

Author

Iannizzotto, A., Frumento, S., Menicucci, D., Callara, A. L., Gemignani, A., Scilingo, E. P., Greco, A., Magjarević, Ratko, Series Editor, Ładyżyński, Piotr, Associate Editor, Ibrahim, Fatimah, Associate Editor, Lackovic, Igor, Associate Editor, Rock, Emilio Sacristan, Associate Editor, Badnjević, Almir, editor, and Gurbeta Pokvić, Lejla, editor

Published
2024
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3. Deriving the respiratory sinus arrhythmia from the heartbeat time series using Empirical Mode Decomposition

Author

Balocchi, R., Menicucci, D., Santarcangelo, E., Sebastiani, L., Gemignani, A., Ghelarducci, B., and Varanini, M.

Subjects
Quantitative Biology - Tissues and Organs, Quantitative Biology - Quantitative Methods
Abstract

Heart rate variability (HRV) is a well-known phenomenon whose characteristics are of great clinical relevance in pathophysiologic investigations. In particular, respiration is a powerful modulator of HRV contributing to the oscillations at highest frequency. Like almost all natural phenomena, HRV is the result of many nonlinearly interacting processes; therefore any linear analysis has the potential risk of underestimating, or even missing, a great amount of information content. Recently the technique of Empirical Mode Decomposition (EMD) has been proposed as a new tool for the analysis of nonlinear and nonstationary data. We applied EMD analysis to decompose the heartbeat intervals series, derived from one electrocardiographic (ECG) signal of 13 subjects, into their components in order to identify the modes associated with breathing. After each decomposition the mode showing the highest frequency and the corresponding respiratory signal were Hilbert transformed and the instantaneous phases extracted were then compared. The results obtained indicate a synchronization of order 1:1 between the two series proving the existence of phase and frequency coupling between the component associated with breathing and the respiratory signal itself in all subjects., Comment: 12 pages, 6 figures. Will be published on "Chaos, Solitons and Fractals"

Published
2003
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31. Cardiac function and oxygen saturation during maximal breath-holding in air and during whole-body surface immersion

Author

Claudio Marabotti, Piaggi P, Menicucci D, Passera M, Benassi A, Bedini R, and L'Abbate A

Subjects
Adult, Male, Time Factors, Diving, Heart Ventricles, Blood Pressure, Ventricular Function, Left, Breath Holding, Oxygen Consumption, Diastole, Immersion, Humans, Cardiomegaly, Exercise-Induced, hypoxia, cardiovascular, Air, Doppler, Breath-hold diving, physiology, diving reflex, cardiovascular, echocardiography, Doppler, hypoxia, Heart, Hemoglobin A, Stroke Volume, Middle Aged, Breath-hold diving, diving reflex, Echocardiography, physiology, Female
Abstract

The magnitude of the oxygen-sparing effect induced by the diving response in humans is still under debate. We wished to compare cardiovascular changes during maximal breath-holding (BH) in air and during whole-body immersion at the surface in a group of BH divers.Twenty-one divers performed a maximal static apnea in air or during whole-body immersion. Dopplerechocardiography, arterial blood pressure and haemoglobin saturation (SaO₂) were obtained at the beginning of, and at 1/3, 2/3 and maximal BH time.BH time was on the average 3.6 ± 0.4 min, with no differences between the two conditions. SaO₂ significantly decreased during BH in both conditions, but was significantly higher during immersion as compared to the dry (P = 0.04). In both conditions, BH induced a significant linear increase in right ventricular diameter (P0.001), left ventricular (LV) volumes (P0.001) and LV stroke volume (P0.001) but a significant linear decrease in LV ejection fraction (P = 0.033). In both conditions, Doppler diastolic parameters showed changes suggesting a constrictive/restrictive left ventricular filling pattern (i.e., an increase of early diastolic left ventricular filling velocity, P = 0.005, and a decrease in the deceleration time of early diastolic left ventricular filling. P0.001).BH induces progressive LV enlargement both in air and whole-body immersion, associated with reduced LV ejection fraction and progressive hindrance to diastolic filling. For a similar apnea duration, SaO₂ decreased less during immersed BH, indicating an O₂-sparing effect of diving, suggesting that interruption of apnea was not triggered by a threshold critical value of blood O₂ desaturation.

Published
2012

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