000168265 001__ 168265
000168265 005__ 20260130164313.0
000168265 0247_ $$2doi$$a10.1088/0967-3334/36/10/2041
000168265 0248_ $$2sideral$$a94139
000168265 037__ $$aART-2015-94139
000168265 041__ $$aeng
000168265 100__ $$0(orcid)0000-0003-0226-4950$$aMartín-Yebra, Alba
000168265 245__ $$aEvaluation of T-wave alternans activity under stress conditions after 5 d and 21 d of sedentary head-down bed rest
000168265 260__ $$c2015
000168265 5060_ $$aAccess copy available to the general public$$fUnrestricted
000168265 5203_ $$aIt is well known that prolonged microgravity leads to cardiovascular deconditioning, inducing significant changes in autonomic control of the cardiovascular system. This may adversely influence cardiac repolarization, and provoke cardiac rhythm disturbances. T-wave alternans (TWA), reflecting temporal and spatial repolarization heterogeneity, could be affected. The aim of this work was to test the hypothesis that 5¿d and 21¿d head-down (-6°) bed rest (HDBR) increases TWA, thus suggesting a higher underlying electrical instability and related arrhythmogenic risk. Forty-four healthy male volunteers were enrolled in the experiments as part of the European Space Agency's HDBR studies. High-fidelity ECG was recorded during orthostatic tolerance (OT) and aerobic power (AP) tests, before (PRE) and after HDBR (POST). A multilead scheme for TWA amplitude estimation was used, where non-normalized and T-wave amplitude normalized TWA indices were computed. In addition, spectral analysis of heart rate variability during OT was assessed. Both 5¿d and 21¿d HDBR induced a reduction in orthostatic tolerance time (OTT), as well as a decrease in maximal oxygen uptake and reserve capacity, thus suggesting cardiovascular deconditioning. However, TWA indices were found not to increase. Interestingly, subjects with lower OTT after 5¿d HDBR also showed higher TWA during recovery after OT testing, associated with unbalanced sympathovagal response, even before the HDBR. In contrast with previous observations, augmented ventricular heterogeneity related to 5¿d and 21¿d HDBR was not sufficient to increase TWA under stress conditions.
000168265 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc-nd$$uhttps://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
000168265 590__ $$a1.576$$b2015
000168265 591__ $$aENGINEERING, BIOMEDICAL$$b46 / 76 = 0.605$$c2015$$dQ3$$eT2
000168265 591__ $$aPHYSIOLOGY$$b64 / 83 = 0.771$$c2015$$dQ4$$eT3
000168265 591__ $$aBIOPHYSICS$$b54 / 72 = 0.75$$c2015$$dQ3$$eT3
000168265 592__ $$a0.828$$b2015
000168265 593__ $$aBiomedical Engineering$$c2015$$dQ2
000168265 593__ $$aPhysiology (medical)$$c2015$$dQ2
000168265 593__ $$aBiophysics$$c2015$$dQ2
000168265 593__ $$aPhysiology$$c2015$$dQ3
000168265 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/acceptedVersion
000168265 700__ $$aCaiani, Enrico
000168265 700__ $$0(orcid)0000-0001-5343-5671$$aMonasterio, Violeta
000168265 700__ $$aPellegrini, Alessandro
000168265 700__ $$0(orcid)0000-0003-3434-9254$$aLaguna, Pablo$$uUniversidad de Zaragoza
000168265 700__ $$0(orcid)0000-0002-7503-3339$$aMartínez, Juan Pablo$$uUniversidad de Zaragoza
000168265 7102_ $$15008$$2800$$aUniversidad de Zaragoza$$bDpto. Ingeniería Electrón.Com.$$cÁrea Teoría Señal y Comunicac.
000168265 773__ $$g36, 10 (2015), 2041-2055$$pPhysiol. meas.$$tPHYSIOLOGICAL MEASUREMENT$$x0967-3334
000168265 8564_ $$s793856$$uhttps://zaguan.unizar.es/record/168265/files/texto_completo.pdf$$yPostprint
000168265 8564_ $$s937029$$uhttps://zaguan.unizar.es/record/168265/files/texto_completo.jpg?subformat=icon$$xicon$$yPostprint
000168265 909CO $$ooai:zaguan.unizar.es:168265$$particulos$$pdriver
000168265 951__ $$a2026-01-30-14:51:15
000168265 980__ $$aARTICLE