{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,16]],"date-time":"2026-04-16T07:14:41Z","timestamp":1776323681470,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2019,5,5]],"date-time":"2019-05-05T00:00:00Z","timestamp":1557014400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>In this study, the linear method of extended partial directed coherence (ePDC) was applied to establish the temporal dynamic behavior of cardiovascular and cardiorespiratory interactions during orthostatic stress at a 70\u00b0 head-up tilt (HUT) test on young age-matched healthy subjects and patients with orthostatic intolerance (OI), both male and female. Twenty 5-min windows were used to analyze the minute-wise progression of interactions from 5 min in a supine position (baseline, BL) until 18 min of the orthostatic phase (OP) without including pre-syncopal phases. Gender differences in controls were present in cardiorespiratory interactions during OP without compromised autonomic regulation. However in patients, analysis by ePDC revealed considerable dynamic alterations within cardiovascular and cardiorespiratory interactions over the temporal course during the HUT test. Considering the young female patients with OI, the information flow from heart rate to systolic blood pressure (mechanical modulation) was already increased before the tilt-up, the information flow from systolic blood pressure to heart rate (neural baroreflex) increased during OP, while the information flow from respiration to heart rate (respiratory sinus arrhythmia) decreased during the complete HUT test. Findings revealed impaired cardiovascular interactions in patients with orthostatic intolerance and confirmed the usefulness of ePDC for causality analysis.<\/jats:p>","DOI":"10.3390\/e21050468","type":"journal-article","created":{"date-parts":[[2019,5,13]],"date-time":"2019-05-13T11:00:57Z","timestamp":1557745257000},"page":"468","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Time-Frequency Analysis of Cardiovascular and Cardiorespiratory Interactions During Orthostatic Stress by Extended Partial Directed Coherence"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2889-1290","authenticated-orcid":false,"given":"Sonia","family":"Charleston-Villalobos","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, Universidad Aut\u00f3noma Metropolitana, Mexico City 09340, Mexico"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8529-6271","authenticated-orcid":false,"given":"Sina","family":"Reulecke","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Universidad Aut\u00f3noma Metropolitana, Mexico City 09340, Mexico"}]},{"given":"Andreas","family":"Voss","sequence":"additional","affiliation":[{"name":"Institute of Innovative Health Technologies, Ernst-Abbe-Hochschule Jena, 07745 Jena, Germany"}]},{"given":"Mahmood R.","family":"Azimi-Sadjadi","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO 80523, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8668-3943","authenticated-orcid":false,"given":"Ram\u00f3n","family":"Gonz\u00e1lez-Camarena","sequence":"additional","affiliation":[{"name":"Department of Health Science, Universidad Aut\u00f3noma Metropolitana, Mexico City 09340, Mexico"}]},{"given":"Mercedes J.","family":"Gait\u00e1n-Gonz\u00e1lez","sequence":"additional","affiliation":[{"name":"Department of Health Science, Universidad Aut\u00f3noma Metropolitana, Mexico City 09340, Mexico"}]},{"given":"Jes\u00fas A.","family":"Gonz\u00e1lez-Hermosillo","sequence":"additional","affiliation":[{"name":"National Institute of Cardiology, Mexico City 14080, Mexico"}]},{"given":"Guadalupe","family":"Hern\u00e1ndez-Pacheco","sequence":"additional","affiliation":[{"name":"National Institute of Cardiology, Mexico City 14080, Mexico"}]},{"given":"Steffen","family":"Schulz","sequence":"additional","affiliation":[{"name":"Institute of Innovative Health Technologies, Ernst-Abbe-Hochschule Jena, 07745 Jena, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1261-6040","authenticated-orcid":false,"given":"Tom\u00e1s","family":"Aljama-Corrales","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Universidad Aut\u00f3noma Metropolitana, Mexico City 09340, Mexico"}]}],"member":"1968","published-online":{"date-parts":[[2019,5,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Faes, L., Erla, S., and Nollo, G. 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