000070678 001__ 70678
000070678 005__ 20191127155455.0
000070678 0247_ $$2doi$$a10.1109/TBME.2017.2758925
000070678 0248_ $$2sideral$$a105199
000070678 037__ $$aART-2018-105199
000070678 041__ $$aeng
000070678 100__ $$aOrini, M.
000070678 245__ $$aA time-varying non-parametric methodology for assessing changes in QT variability unrelated to heart rate variability.
000070678 260__ $$c2018
000070678 5060_ $$aAccess copy available to the general public$$fUnrestricted
000070678 5203_ $$aObjective: To propose and test a novel methodology to measure changes in QT interval variability (QTV) unrelated to RR interval variability (RRV) in non-stationary conditions. Methods: Time-frequency coherent and residual spectra repre- senting QTV related (QTVrRRV) and unrelated (QTVuRRV) to RRV, respectively, are estimated using time-frequency Cohen’s class distributions. The proposed approach decomposes the non- stationary output spectrum of any two-input one-output model with uncorrelated inputs into two spectra representing the information related and unrelated to one of the two inputs, respectively. An algorithm to correct for the bias of the time- frequency coherence function between QTV and RRV is proposed to provide accurate estimates of both QTVuRRV and QTVrRRV. Two simulation studies were conducted to assess the methodol- ogy in challenging non-stationary conditions and data recorded during head-up tilt in 16 healthy volunteers were analyzed. Results: In the simulation studies, QTVuRRV changes were tracked with only a minor delay due to the filtering necessary to estimate the non-stationary spectra. The correlation coefficient between theoretical and estimated patterns was > 0.92 even for extremely noisy recordings (SNR in QTV = -10dB). During head-up tilt, QTVrRRV explained the largest proportion of QTV, whereas QTVuRRV showed higher relative increase than QTV or QTVrRRV in all spectral bands (P = 0.05 for most pairwise comparisons).
Conclusion: The proposed approach accurately tracks changes in QTVuRRV. Head-up tilt induced a slightly greater increase in QTVuRRV than in QTVrRRV.
Significance: The proposed index QTVuRRV may represent an indirect measure of intrinsic ventricular repolarization variabil- ity, a marker of cardiac instability associated with sympathetic ventricular modulation and sudden cardiac death.
000070678 540__ $$9info:eu-repo/semantics/openAccess$$aAll rights reserved$$uhttp://www.europeana.eu/rights/rr-f/
000070678 590__ $$a4.491$$b2018
000070678 591__ $$aENGINEERING, BIOMEDICAL$$b11 / 80 = 0.138$$c2018$$dQ1$$eT1
000070678 592__ $$a1.256$$b2018
000070678 593__ $$aBiomedical Engineering$$c2018$$dQ1
000070678 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/submittedVersion
000070678 700__ $$0(orcid)0000-0002-1960-407X$$aPueyo, E.$$uUniversidad de Zaragoza
000070678 700__ $$0(orcid)0000-0003-3434-9254$$aLaguna, P.$$uUniversidad de Zaragoza
000070678 700__ $$0(orcid)0000-0003-1272-0550$$aBailón, R.$$uUniversidad de Zaragoza
000070678 7102_ $$15008$$2800$$aUniversidad de Zaragoza$$bDpto. Ingeniería Electrón.Com.$$cÁrea Teoría Señal y Comunicac.
000070678 773__ $$g68, 7 (2018), 1443-1451$$pIEEE trans. biomed. eng.$$tIEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING$$x0018-9294
000070678 8564_ $$s1521033$$uhttps://zaguan.unizar.es/record/70678/files/texto_completo.pdf$$yPreprint
000070678 8564_ $$s146914$$uhttps://zaguan.unizar.es/record/70678/files/texto_completo.jpg?subformat=icon$$xicon$$yPreprint
000070678 909CO $$ooai:zaguan.unizar.es:70678$$particulos$$pdriver
000070678 951__ $$a2019-11-27-15:46:54
000070678 980__ $$aARTICLE