QT INTERVAL CHANGES AT HIGH ALTITUDE: A NARRATIVE REVIEW OF CARDIOVASCULAR RISK AND THE ROLE OF WEARABLE TECHNOLOGIES IN REMOTE MONITORING

Katarzyna Apanasewicz; Marta Kamrowska; Jakub Świech; Filip Kopacki; Weronika Szczeblewska; Daniel Jaskot; Jakub Marzec; Natalia Kita; Natalia Sztenc; Patrycja Broniszewska

doi:10.31435/ijitss.2(50).2026.5483

Authors

Katarzyna Apanasewicz J. Strus Multidisciplinary Municipal Hospital in Poznań, Poland https://orcid.org/0009-0001-0765-5398
Marta Kamrowska University Clinical Hospital No. 2 of Pomeranian Medical University in Szczecin, Poland https://orcid.org/0009-0001-1570-0144
Jakub Świech University Clinical Hospital No. 2 of Pomeranian Medical University in Szczecin, Poland https://orcid.org/0009-0001-1732-4162
Filip Kopacki University Clinical Hospital No. 2 of Pomeranian Medical University in Szczecin, Poland https://orcid.org/0009-0005-7897-8222
Weronika Szczeblewska Independent Public Provincial Integrated Hospital in Szczecin, Poland https://orcid.org/0009-0007-3956-622X
Daniel Jaskot Independent Public Provincial Integrated Hospital in Szczecin, Poland https://orcid.org/0009-0004-8678-9838
Jakub Marzec University Clinical Hospital No. 1 of Pomeranian Medical University in Szczecin, Poland https://orcid.org/0009-0007-8336-7260
Natalia Kita University Clinical Hospital No. 2 of Pomeranian Medical University in Szczecin, Poland https://orcid.org/0009-0001-2277-6198
Natalia Sztenc Pomeranian Medical University, Szczecin, Poland https://orcid.org/0009-0006-4307-7958
Patrycja Broniszewska University Clinical Hospital No. 2 of Pomeranian Medical University in Szczecin, Poland https://orcid.org/0009-0000-6577-307X

DOI:

https://doi.org/10.31435/ijitss.2(50).2026.5483

Keywords:

QT Interval; High Altitude; Ventricular Repolarization; Wearable Technology; Cardiac Risk; Telemedicine

Abstract

High-altitude exposure induces a range of cardiovascular and electrophysiological adaptations driven primarily by hypobaric hypoxia, autonomic imbalance, and changes in pulmonary hemodynamics. Among these adaptations, alterations in ventricular repolarization, including prolongation of the QT interval and corrected QT (QTc), have attracted increasing attention because of their potential association with arrhythmic risk in both healthy individuals and vulnerable populations. Previous studies have described electrocardiographic changes at altitude, and more recent evidence indicates that QTc may increase during acute or short-term high-altitude exposure and in selected clinical groups, such as patients with obstructive sleep apnea or high-altitude pulmonary hypertension.

This narrative review synthesizes current evidence on QT interval changes at high altitude, assesses their potential clinical significance, and evaluates the emerging role of wearable technologies in remote cardiac monitoring under extreme environmental conditions. A structured literature search was conducted using major databases, including PubMed/MEDLINE, Scopus, and Web of Science.

The available evidence suggests that high altitude may contribute to measurable changes in ventricular repolarization, although the magnitude, persistence, and clinical implications of these alterations remain heterogeneous across studies. Wearable and smartwatch-based ECG technologies offer promising opportunities for remote surveillance; however, current evidence indicates that QT assessment with such devices still requires careful validation and expert interpretation.

These findings may be relevant for clinicians, travelers, and healthcare systems seeking safer strategies for cardiovascular risk assessment in remote and high-altitude environments.

References

Aeschbacher, S. S., Latshang, T. D., Sheraliev, U., Marazhapov, N. H., Mirrakhimov, E., Sooronbaev, T. M., Ulrich, S., Furian, M., Bloch, K. E., & Duru, F. (2021). Altered cardiac repolarisation in highlanders with high-altitude pulmonary hypertension during wakefulness and sleep. Journal of Sleep Research, 30(3), e13153. https://doi.org/10.1111/jsr.13153

Batmaz, G., Aksoy, A. N., Aydin, S., Ay, N. K., & Dane, B. (2016). QT interval changes in term pregnant women living at moderately high altitude. Nigerian Journal of Clinical Practice, 19(5), 611–615. https://doi.org/10.4103/1119-3077.188707

Bärtsch, P., & Gibbs, J. S. R. (2007). Effect of altitude on the heart and lungs. Circulation, 116(19), 2191–2202. https://doi.org/10.1161/CIRCULATIONAHA.106.650796

Couderc, J. P. (2010). Measurement and regulation of cardiac ventricular repolarization: From QT interval to T-wave morphology. Annals of Noninvasive Electrocardiology, 15(3), 209–215. https://doi.org/10.1111/j.1542-474X.2010.00367.x

Drew, B. J., Califf, R. M., Funk, M., Kaufman, E. S., Krucoff, M. W., Laks, M. M., Macfarlane, P. W., Sommargren, C., Swiryn, S., & Van Hare, G. F. (2010). Practice standards for electrocardiographic monitoring in hospital settings: An American Heart Association scientific statement. Circulation, 122(24), 272–292. https://doi.org/10.1161/CIR.0b013e3181f96b4c

Duncker, D., Ding, W. Y., Etheridge, S., Noseworthy, P. A., Veltmann, C., Yao, X., Bunch, T. J., & Gupta, D. (2021). Smart wearables for cardiac monitoring—Real-world use beyond atrial fibrillation. Sensors, 21(7), 2539. https://doi.org/10.3390/s21072539

Furian, M., Latshang, T. D., Aeschbacher, S. S., Sheraliev, U., Marazhapov, N. H., Mirrakhimov, E., Ulrich, S., Sooronbaev, T. M., & Bloch, K. E. (2021). Markers of cardiovascular risk and their reversibility with acute oxygen therapy in Kyrgyz highlanders with high altitude pulmonary hypertension. Pulmonology, 27(5), 394–402. https://doi.org/10.1016/j.pulmoe.2021.02.001

Goldenberg, I., Moss, A. J., & Zareba, W. (2006). QT interval: How to measure it and what is “normal.” Journal of Cardiovascular Electrophysiology, 17(3), 333–336. https://doi.org/10.1111/j.1540-8167.2006.00408.x

Gudelunas, K., Chinn, G. A., Barreto-Chang, O. L., Campbell, L., & Sall, J. W. (2025). A 4-day exposure to high altitude prolongs QTc in healthy human subjects. Wilderness & Environmental Medicine, 36, 176–181. https://doi.org/10.1177/10806032251314740

Hoek, L. J., Brouwer, J. L. P., Voors, A. A., & Maass, A. H. (2023). Smart devices to measure and monitor QT intervals: A systematic review. Frontiers in Cardiovascular Medicine, 10, 1172666. https://doi.org/10.3389/fcvm.2023.1172666

Horii, M., Takasaki, I., Ohtsuka, K., Tsukiyama, H., Takahashi, A., & Doi, Y. (1987). Changes of heart rate and QT interval at high altitude in alpinists: Analysis by Holter ambulatory electrocardiogram. Clinical Cardiology, 10(4), 238–242. https://doi.org/10.1002/clc.4960100406

Karliner, J. S., Sarnquist, F. F., Graber, D. J., Peters, R. M., Jr., & West, J. B. (1985). The electrocardiogram at extreme altitude: Experience on Mt. Everest. American Heart Journal, 109(3), 505–513. https://doi.org/10.1016/0002-8703(85)90555-1

Koshy, A. N., Sajeev, J. K., Nerlekar, N., Brown, A. J., Rajakariar, K., Zureik, M., Wong, M. C., Roberts, L., Street, M., Cooke, J., Teh, A. W., & Sanders, P. (2018). Smart watches for heart rate assessment in atrial arrhythmias. Heart, Lung and Circulation, 27(2), 132–138. https://doi.org/10.1016/j.hlc.2017.05.129

Latshang, T. D., Kaufmann, B., Nussbaumer-Ochsner, Y., Ulrich, S., Furian, M., Kohler, M., Thurnheer, R., Saguner, A. M., Duru, F., & Bloch, K. E. (2016). Patients with obstructive sleep apnea have cardiac repolarization disturbances when travelling to altitude: Randomized, placebo-controlled trial of acetazolamide. Sleep, 39(9), 1631–1637. https://doi.org/10.5665/sleep.6080

Liu, Z., Yang, J., Yang, B., Sun, M., Ye, X., Yu, S., Tan, H., Hu, M., Lv, H., Wu, B., Gao, X., & Huang, L. (2024). Effect of ubiquinol on electrophysiology during high-altitude acclimatization and de-acclimatization: A substudy of the Shigatse CARdiorespiratory fitness (SCARF) randomized clinical trial. International Journal of Cardiology, 401, 131817. https://doi.org/10.1016/j.ijcard.2024.131817

Maille, B., Wilkin, M., Million, M., Rességuier, N., Franceschi, F., Koutbi-Franceschi, L., Hourdain, J., Martinez, E., Zabern, M., Gardella, C., Tissot-Dupont, H., Singh, J. P., Deharo, J.-C., & Fiorina, L. (2021). Smartwatch electrocardiogram and artificial intelligence for assessing cardiac-rhythm safety of drug therapy in the COVID-19 pandemic: The QT-logs study. International Journal of Cardiology, 331, 333–339. https://doi.org/10.1016/j.ijcard.2021.01.002

Mannhart, D., Hennings, E., Lischer, M., Vernier, C., Du Fay de Lavallaz, J., Knecht, S., Schaer, B., Osswald, S., Kühne, M., Sticherling, C., & Badertscher, P. (2022). Clinical validation of automated corrected QT-interval measurements from a single-lead electrocardiogram using a novel smartwatch. Frontiers in Cardiovascular Medicine, 9, 906079. https://doi.org/10.3389/fcvm.2022.906079

Perez, M. V., Mahaffey, K. W., Hedlin, H., Rumsfeld, J. S., Garcia, A., Ferris, T., Balasubramanian, V., Russo, A. M., Rajmane, A., Cheung, L., Hung, G., Lee, J., Kowey, P., Talati, N., Nag, D., Gummidipundi, S. E., Beatty, A. L., Hills, M. T., Desai, S., & Turakhia, M. P. (2019). Large-scale assessment of a smartwatch to identify atrial fibrillation. New England Journal of Medicine, 381(20), 1909–1917. https://doi.org/10.1056/NEJMoa1901183

Roden, D. M. (2004). Drug-induced prolongation of the QT interval. New England Journal of Medicine, 350(10), 1013–1022. https://doi.org/10.1056/NEJMra032426

Saghir, N., Aggarwal, A., Soneji, N., Valencia, V., Rodgers, G., & Kurian, T. (2020). A comparison of manual electrocardiographic interval and waveform analysis in lead I of 12-lead ECG and Apple Watch ECG: A validation study. Cardiovascular Digital Health Journal, 1(1), 30–36. https://doi.org/10.1016/j.cvdhj.2020.07.002

Sana, F., Isselbacher, E. M., Singh, J. P., Heist, E. K., Pathik, B., & Armoundas, A. A. (2020). Wearable devices for ambulatory cardiac monitoring: JACC state-of-the-art review. Journal of the American College of Cardiology, 75(13), 1582–1592. https://doi.org/10.1016/j.jacc.2020.01.046

Saurenmann, P., & Koller, E. A. (1984). The ECG changes due to altitude and to catecholamines. European Journal of Applied Physiology, 53(1), 35–42.

Schwartz, P. J., Crotti, L., & Insolia, R. (2012). Long QT syndrome: From genetics to management. Circulation, 126(9), 1047–1058. https://doi.org/10.1161/CIRCULATIONAHA.111.060061

Somers, V. K., Mark, A. L., & Abboud, F. M. (1993). Sympathetic activation by hypoxia and sleep apnea. Circulation, 87(1), 189–197.

Steinhubl, S. R., Muse, E. D., & Topol, E. J. (2015). The emerging field of mobile health. Science Translational Medicine, 7(283), 283rv3. https://doi.org/10.1126/scitranslmed.aaa3487

Tison, G. H., Sanchez, J. M., Ballinger, B., Singh, A., Olgin, J. E., Pletcher, M. J., & Marcus, G. M. (2018). Passive detection of atrial fibrillation using a commercially available smartwatch. JAMA Cardiology, 3(5), 409–416. https://doi.org/10.1001/jamacardio.2018.0136

Vandenberk, B., Vandael, E., Robyns, T., Vandenberghe, J., Garweg, C., Ector, J., Willems, R., & Foulon, V. (2016). Which QT correction formulae to use for QT monitoring? Journal of the American Heart Association, 5(6), e003264. https://doi.org/10.1161/JAHA.116.003264

West, J. B. (2012). High-altitude medicine. American Journal of Respiratory and Critical Care Medicine, 186(12), 1229–1237. https://doi.org/10.1164/rccm.201207-1323CI

Windsor, J. S., Rodway, G. W., & Montgomery, H. E. (2010). A review of electrocardiography in the high altitude environment. High Altitude Medicine & Biology, 11(2), 51–60. https://doi.org/10.1089/ham.2009.1065

Woods, D. R., Begley, J., & Stacey, M. (2011). Cardiac arrhythmias at high altitude. High Altitude Medicine & Biology, 12(1), 35–41. https://doi.org/10.1089/ham.2010.1057