{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,15]],"date-time":"2026-08-15T09:13:11Z","timestamp":1786785191000,"version":"build-2736575974"},"reference-count":33,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,2,7]],"date-time":"2026-02-07T00:00:00Z","timestamp":1770422400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Galician Society of Respiratory Pathology","award":["EUR 15,000"],"award-info":[{"award-number":["EUR 15,000"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Objectives: Unexplained syncope (US) persists despite extensive diagnostic evaluations, with autonomic dysfunction as a central mechanism. Sleep apnea (SA) may contribute through intermittent hypoxemia and autonomic imbalance. We evaluated the impact of SA treatment on syncope recurrence, nocturnal heart rate variability (HRV), and quality of life in patients with US. Methods: We conducted a prospective multicentre study in three hospitals in Galicia (Spain), including adults with US who underwent home respiratory polygraphy. SA was diagnosed according to guideline criteria, and treatment was prescribed when indicated (positive airway pressure therapy, positional therapy, and\/or weight management). Symptoms, syncope burden, nocturnal heart rate variability derived from the ECG signal, and quality of life (SF-36 and a 0\u2013100 visual analogue scale) were assessed at baseline and after 12 months. Results: Of 141 patients, 99 met treatment criteria, and 67 completed the 12-month follow-up. Mean age was 64.5 years; 59.6% were men; mean AHI was 25.9\/h. After therapy, daytime sleepiness (Epworth score decreased from 8 to 5; p = 0.001), fatigue, nocturnal awakenings, and syncopal episodes decreased from 62.6% to 16.2%, 56.6% to 16.2%, and 3 to 0, respectively (all p &lt; 0.001). HRV showed increased RR interval (p &lt; 0.001) and RMSSD (p = 0.04). Quality of life improved in vitality (SF-36 vitality domain increased from 44 to 50; p = 0.02) and on the visual analogue scale (0\u2013100: 50 to 70; p = 0.002). Conclusions: In this prospective cohort of patients with US and SA, therapy for SA was associated with fewer syncope recurrences, improvements in nocturnal respiratory indices, and selected heart rate variability measures, and better self-reported fatigue and vitality. Given the single-arm design and potential adherence and selection biases, these findings should be interpreted with caution and warrant confirmation in controlled studies.<\/jats:p>","DOI":"10.3390\/jcm15041318","type":"journal-article","created":{"date-parts":[[2026,2,9]],"date-time":"2026-02-09T08:15:54Z","timestamp":1770624954000},"page":"1318","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Impact of Sleep Apnea Treatment in Patients with Unexplained Syncope: The SINCOSAS Study"],"prefix":"10.3390","volume":"15","author":[{"given":"Mar\u00eda-Jos\u00e9","family":"Mu\u00f1oz-Mart\u00ednez","sequence":"first","affiliation":[{"name":"Pulmonary Department, Hospital \u00c1lvaro Cunqueiro, 36312 Vigo, Spain"},{"name":"NeumoVigo I+i Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36312 Vigo, Spain"},{"name":"Faculty of Medicine and Dentistry, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1494-8145","authenticated-orcid":false,"given":"Manuel","family":"Casal-Guisande","sequence":"additional","affiliation":[{"name":"NeumoVigo I+i Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36312 Vigo, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red, CIBERES ISCIII, 28029 Madrid, Spain"},{"name":"Department of Design in Engineering, University of Vigo, 36208 Vigo, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bernardo","family":"Sope\u00f1a","sequence":"additional","affiliation":[{"name":"Faculty of Medicine and Dentistry, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain"},{"name":"Internal Medicine Department, Hospital Cl\u00ednico Universitario de Santiago de Compostela, 15782 Santiago de Compostela, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6710-3766","authenticated-orcid":false,"given":"Mar\u00eda","family":"Torres-Dur\u00e1n","sequence":"additional","affiliation":[{"name":"Pulmonary Department, Hospital \u00c1lvaro Cunqueiro, 36312 Vigo, Spain"},{"name":"NeumoVigo I+i Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36312 Vigo, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red, CIBERES ISCIII, 28029 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Enrique","family":"Garc\u00eda-Campo","sequence":"additional","affiliation":[{"name":"Cardiology Department, Hospital \u00c1lvaro Cunqueiro, 36312 Vigo, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1239-5276","authenticated-orcid":false,"given":"Dolores","family":"Corbacho-Abelaira","sequence":"additional","affiliation":[{"name":"NeumoVigo I+i Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36312 Vigo, Spain"},{"name":"Pulmonary Department, Hospital Ribera Povisa, 36211 Vigo, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-3764-2952","authenticated-orcid":false,"given":"Ana","family":"Souto-Alonso","sequence":"additional","affiliation":[{"name":"Pulmonary Department, Hospital Universitario de A Coru\u00f1a, 15006 A Coru\u00f1a, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alberto","family":"Fern\u00e1ndez-Villar","sequence":"additional","affiliation":[{"name":"Pulmonary Department, Hospital \u00c1lvaro Cunqueiro, 36312 Vigo, Spain"},{"name":"NeumoVigo I+i Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36312 Vigo, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red, CIBERES ISCIII, 28029 Madrid, Spain"},{"name":"School of Industrial Engineering, University of Vigo, 36310 Vigo, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1883","DOI":"10.1093\/eurheartj\/ehy037","article-title":"2018 ESC Guidelines for the Diagnosis and Management of Syncope","volume":"39","author":"Brignole","year":"2018","journal-title":"Eur. 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