{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T14:49:35Z","timestamp":1792507775446,"version":"4.5.0"},"reference-count":22,"publisher":"SAGE Publications","issue":"2","license":[{"start":{"date-parts":[[2025,2,24]],"date-time":"2025-02-24T00:00:00Z","timestamp":1740355200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"funder":[{"DOI":"10.13039\/501100004518","name":"Tasly Holding Group","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004518","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Wilderness &amp; Environmental Medicine"],"published-print":{"date-parts":[[2025,6]]},"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Long QTc syndrome can predispose patients to fatal ventricular arrhythmias. We studied the effects of a rapid ascent and a multiday stay at high altitude on QTc interval.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      We recorded electrocardiograms (ECGs) on study subjects at sea level and then again after a 1-d ascent to 3800\u2005m. Two sea-level ECGs were recorded at the initial screening visit (SL1) and 14 days later (SL2). Altitude ECGs were recorded at approximately 16 and 86\u2005h after arrival. SpO\n                      <jats:sub>2<\/jats:sub>\n                      was recorded prior to each ECG measurement. We defined prolonged QTc as a QTc interval &gt;450\u2005ms for men and &gt;470\u2005ms for women. We used multivariate analysis to analyze the QTc interval for the effect of drugs, altitude, and changes in electrolytes.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      We enrolled 107 subjects: 61 males and 46 females between the ages of 19 and 54 y, with a median age of 34 y. QTcF (QT interval for varying heart rates using Fridericia's formula) at SL1 was 405\u00b117\u2005ms; at SL2, 404\u00b117\u2005ms; at 16\u2005h, 411\u00b118\u2005ms; and at 86\u2005h, 427\u00b124\u2005ms. After 86\u2005h at altitude, 12 participants met the criteria for prolonged QT syndrome, and 61% of subjects had QTc prolongation of &gt;20\u2005ms from sea-level values. This was independent of changes in serum electrolyte levels, (i.e., sodium, potassium, and calcium), bicarbonate levels, and SpO\n                      <jats:sub>2<\/jats:sub>\n                      .\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>High altitude exposure can lengthen a healthy adult's QTc interval by more than 20\u2005ms. It remains unknown whether this increase might raise the risk of torsades de pointes in people with long QT intervals at baseline.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/10806032251314740","type":"journal-article","created":{"date-parts":[[2025,2,24]],"date-time":"2025-02-24T03:57:32Z","timestamp":1740369452000},"page":"176-181","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":3,"title":["A 4-Day Exposure to High Altitude Prolongs QTc in Healthy Human Subjects"],"prefix":"10.1177","volume":"36","author":[{"given":"Koa","family":"Gudelunas","sequence":"first","affiliation":[{"name":"Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA"},{"name":"Vital Signs Research Group, San Francisco, CA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gregory A.","family":"Chinn","sequence":"additional","affiliation":[{"name":"Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4781-404X","authenticated-orcid":false,"given":"Odmara L.","family":"Barreto-Chang","sequence":"additional","affiliation":[{"name":"Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leah","family":"Campbell","sequence":"additional","affiliation":[{"name":"Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1725-5654","authenticated-orcid":false,"given":"Jeffrey W.","family":"Sall","sequence":"additional","affiliation":[{"name":"Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2025,2,24]]},"reference":[{"key":"e_1_3_3_2_2","unstructured":"Tourism\u2019s Potential for Mountain Ecosystems and Communities Outlined in New Report. (2023 April 26). UN World Tourism Organization."},{"key":"e_1_3_3_3_2","doi-asserted-by":"publisher","DOI":"10.2174\/1573403X10666140514103612"},{"key":"e_1_3_3_4_2","volume-title":"Statpearls","author":"Cohagan B","year":"2024","unstructured":"Cohagan B, Brandis D. Torsade de pointes. In: Statpearls. StatPearls Publishing; 2024. http:\/\/www.ncbi.nlm.nih.gov\/books\/NBK459388\/"},{"key":"e_1_3_3_5_2","doi-asserted-by":"publisher","DOI":"10.3390\/ijms20061324"},{"key":"e_1_3_3_6_2","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2125.2002.01627.x"},{"issue":"5","key":"e_1_3_3_7_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0033-0620(01)00027-5","article-title":"The QT interval","volume":"43","author":"Bednar MM","year":"2001","unstructured":"Bednar MM, Harrigan EP, Anziano RJ, Camm AJ, Ruskin JN. The QT interval. Prog Cardiovasc Dis. 2001;43(5 suppl 1):1\u201345.","journal-title":"Prog Cardiovasc Dis"},{"key":"e_1_3_3_8_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2125.2010.03660.x"},{"key":"e_1_3_3_9_2","doi-asserted-by":"publisher","DOI":"10.1136\/postgradmedj-2020-138661"},{"key":"e_1_3_3_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0002-9149(03)00040-7"},{"key":"e_1_3_3_11_2","doi-asserted-by":"publisher","DOI":"10.1136\/thx.2010.151712"},{"key":"e_1_3_3_12_2","doi-asserted-by":"publisher","DOI":"10.1002\/clc.4960100406"},{"key":"e_1_3_3_13_2","doi-asserted-by":"publisher","DOI":"10.1001\/archinte.1966.00290140036008"},{"key":"e_1_3_3_14_2","doi-asserted-by":"publisher","DOI":"10.1016\/0002-8703(68)90019-7"},{"key":"e_1_3_3_15_2","doi-asserted-by":"publisher","DOI":"10.1161\/CIRCULATIONAHA.114.013144"},{"key":"e_1_3_3_16_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.wem.2023.09.002"},{"key":"e_1_3_3_17_2","doi-asserted-by":"publisher","DOI":"10.1161\/JAHA.116.003264"},{"key":"e_1_3_3_18_2","unstructured":". US Dept of Heal and Human Services US Food and Drug Administration Center for Drug Evaluation and Research Center for Biologics Evaluation and Research. Guidance for Industry: E14 Clinical Evaluation of QT\/QTc Interval Prolongation and Proarrhythmic Potential for Non-Antiarrhythmic Drugs. 2005."},{"key":"e_1_3_3_19_2","volume-title":"Statpearls","author":"Al-Akchar M","year":"2022","unstructured":"Al-Akchar M, Siddique MS. Long QT syndrome. In: Statpearls. StatPearls Publishing; 2022."},{"key":"e_1_3_3_20_2","doi-asserted-by":"publisher","DOI":"10.1007\/s12291-010-0088-9"},{"key":"e_1_3_3_21_2","volume-title":"Statpearls","author":"Ulloa NA","year":"2023","unstructured":"Ulloa NA, Cook J. Altitude induced pulmonary hypertension. In: Statpearls. 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