{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T15:12:42Z","timestamp":1789139562937,"version":"build-2803163510"},"reference-count":36,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T00:00:00Z","timestamp":1789084800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Clin. Med.","JCM"],"abstract":"<jats:p>Background\/Objectives: Acute hypercapnic respiratory failure is associated with significant morbidity and mortality despite advances in non-invasive mechanical ventilation (NIMV) therapy. The frontal QRS-T angle is a simple electrocardiographic marker reflecting ventricular depolarization\u2013repolarization heterogeneity and has been associated with adverse cardiovascular outcomes. However, the relationship between dynamic changes in frontal QRS-T angle and NIMV treatment response in acute hypercapnic respiratory failure remains unclear. This study aimed to evaluate the association between frontal QRS-T angle changes after NIMV treatment and clinical outcomes in patients with acute hypercapnic respiratory failure. Methods: This retrospective observational cohort study included 186 adult patients hospitalized with acute hypercapnic respiratory failure and treated with bilevel positive airway pressure between January 2024 and December 2025. Frontal QRS-T angle values were obtained from standard 12-lead electrocardiograms recorded before NIMV initiation (T0) and at the 24th hour of treatment (T24). Clinical, laboratory, arterial blood gas, and electrocardiographic parameters were analyzed. Receiver operating characteristic (ROC) analysis, Kaplan\u2013Meier survival analysis, correlation analysis, and multivariable logistic regression analysis were performed to evaluate the prognostic significance of frontal QRS-T angle. Results: Successful NIMV treatment was achieved in 143 patients (76.9%), whereas 43 patients (23.1%) experienced NIMV failure. Patients with failed NIMV treatment had significantly higher baseline frontal QRS-T angle values compared with the successful group [128\u00b0 (94\u2013156) vs. 71\u00b0 (48\u2013101), p &lt; 0.001]. Frontal QRS-T angle significantly decreased after treatment in the successful NIMV group but not in the failed group. A significant positive correlation was observed between \u0394PaCO2 and \u0394frontal QRS-T angle (r = 0.624, p &lt; 0.001). ROC analysis demonstrated that baseline frontal QRS-T angle predicted NIMV failure with an AUC of 0.842 (95% CI: 0.773\u20130.898) and in-hospital mortality with an AUC of 0.811 (95% CI: 0.735\u20130.873). Kaplan\u2013Meier analysis showed significantly lower survival rates in patients with frontal QRS-T angle &gt;90\u00b0 (log-rank p &lt; 0.001). Multivariable logistic regression analysis identified frontal QRS-T angle &gt;90\u00b0 as an independent predictor of in-hospital mortality (OR: 3.617, 95% CI: 1.484\u20138.813, p = 0.005). Conclusions: Baseline frontal QRS-T angle was associated with NIMV failure and in-hospital mortality, while its 24-h change was associated with physiological response among patients with paired T0\u2013T24 measurements. These findings are hypothesis-generating and do not establish the utility of frontal QRS-T angle monitoring for immediate escalation or intubation decisions.<\/jats:p>","DOI":"10.3390\/jcm15187066","type":"journal-article","created":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T14:39:24Z","timestamp":1789137564000},"page":"7066","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Baseline and 24-Hour Changes in the Frontal QRS-T Angle During Non-Invasive Ventilation and Their Association with Clinical Outcomes in Acute Hypercapnic Respiratory Failure"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8659-0691","authenticated-orcid":false,"given":"Murat","family":"Karamanl\u0131o\u011flu","sequence":"first","affiliation":[{"name":"Department of Cardiology, Ankara Atat\u00fcrk Sanatorium Training and Research Hospital, University of Health Sciences, Ankara 06280, 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Care Clin."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"973","DOI":"10.4187\/respcare.10560","article-title":"Acute Hypercapnic Respiratory Failure in COPD","volume":"68","author":"MacIntyre","year":"2023","journal-title":"Respir. Care"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1016\/j.jsmc.2024.04.001","article-title":"Pathophysiology of Chronic Hypercapnic Respiratory Failure","volume":"19","author":"Nanayakkara","year":"2024","journal-title":"Sleep Med. Clin."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"ii1","DOI":"10.1136\/thoraxjnl-2015-208209","article-title":"BTS\/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults","volume":"71","author":"Davidson","year":"2016","journal-title":"Thorax"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1156","DOI":"10.1111\/resp.13445","article-title":"Non-invasive ventilation: Essential requirements and clinical skills for successful practice","volume":"24","author":"Elliott","year":"2018","journal-title":"Respirology"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"306","DOI":"10.4103\/atm.atm_683_20","article-title":"Bilevel positive airway pressure ventilation for non-COPD acute hypercapnic respiratory failure patients","volume":"16","author":"Faqihi","year":"2021","journal-title":"Ann. Thorac. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"496","DOI":"10.1186\/s13054-025-05730-y","article-title":"A clinical guide to non-invasive respiratory support in acute respiratory failure: Ventilation settings, technical optimization and clinical indications","volume":"29","author":"Rezoagli","year":"2025","journal-title":"Crit. Care"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"32","DOI":"10.4274\/ThoracResPract.2024.23076","article-title":"Non-invasive Mechanical Ventilation in Lung Cancer: Physiological Principles and Clinical Utilization in Surgical and Non-surgical Settings","volume":"26","author":"Cascella","year":"2025","journal-title":"Thorac. Res. Pract."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1193","DOI":"10.1080\/17476348.2025.2529540","article-title":"A clinicians\u2019 guide to non-invasive ventilation for exacerbated chronic obstructive pulmonary disease","volume":"19","author":"Panzuti","year":"2025","journal-title":"Expert Rev. Respir. Med."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1602426","DOI":"10.1183\/13993003.02426-2016","article-title":"Official ERS\/ATS clinical practice guidelines: Noninvasive ventilation for acute respiratory failure","volume":"50","author":"Rochwerg","year":"2017","journal-title":"Eur. Respir. J."},{"key":"ref_11","first-page":"CD004104","article-title":"Non-invasive ventilation for the management of acute hypercapnic respiratory failure due to exacerbation of chronic obstructive pulmonary disease","volume":"2017","author":"Osadnik","year":"2017","journal-title":"Cochrane Database Syst. Rev."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s43168-023-00203-8","article-title":"NIV failure in respiratory failure: An analysis","volume":"17","author":"Abraham","year":"2023","journal-title":"Egypt. J. Bronchol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"111434","DOI":"10.5492\/wjccm.v14.i4.111434","article-title":"Pathophysiology and management of right ventricular failure in critically ill patients: A narrative review","volume":"14","author":"Kermanian","year":"2025","journal-title":"World J. Crit. Care Med."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"636","DOI":"10.1002\/ppul.24776","article-title":"Intensive care management of right ventricular failure and pulmonary hypertension crises","volume":"56","author":"Coleman","year":"2021","journal-title":"Pediatr. Pulmonol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1659","DOI":"10.21037\/cdt-20-348","article-title":"Treatment of right ventricular dysfunction and heart failure in pulmonary arterial hypertension","volume":"10","author":"Inampudi","year":"2020","journal-title":"Cardiovasc. Diagn. Ther."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"153086","DOI":"10.1016\/j.prp.2020.153086","article-title":"Can COVID 2019 induce a specific cardiovascular damage or it exacerbates pre-existing cardiovascular diseases?","volume":"216","author":"Mansueto","year":"2020","journal-title":"Pathol. Res. Pract."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"678","DOI":"10.1161\/CIRCULATIONAHA.116.022362","article-title":"Systemic Consequences of Pulmonary Hypertension and Right-Sided Heart Failure","volume":"141","author":"Rosenkranz","year":"2020","journal-title":"Circulation"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s40635-020-00307-1","article-title":"Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest","volume":"8","author":"Robba","year":"2020","journal-title":"Intensive Care Med. Exp."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"214","DOI":"10.1152\/japplphysiol.00113.2019","article-title":"The interactions between respiratory and cardiovascular systems in systolic heart failure","volume":"128","author":"Cross","year":"2020","journal-title":"J. Appl. Physiol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"402","DOI":"10.1080\/10641963.2021.1890766","article-title":"The frontal plane QRS-T angle may affect our perspective on prehypertension: A prospective study","volume":"43","author":"Aksoy","year":"2021","journal-title":"Clin. Exp. Hypertens."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Young, W., Srinivasan, N., Tinker, A., Munroe, P., Lambiase, P., and Orini, M. (2020). Comparison of the spatial QRS-T angle With Intra-cardiac Markers of Depolarisation and Repolarisation. Proceedings of the 2020 Computing in Cardiology Conference (CinC), IEEE.","DOI":"10.22489\/CinC.2020.414"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Ciucurel, C., and Iconaru, E.I. (2023). The Relationship between the Frontal QRS-T Angle on ECG and Physical Activity Level in Young Adults. Int. J. Environ. Res. Public Health, 20.","DOI":"10.3390\/ijerph20032411"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"967","DOI":"10.1016\/j.jelectrocard.2018.08.028","article-title":"Prognostic value of frontal QRS-T angle in patients undergoing myocardial revascularization or cardiac valve surgery","volume":"51","author":"Lazzeroni","year":"2018","journal-title":"J. Electrocardiol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"308","DOI":"10.1111\/resp.13469","article-title":"Benefits of non-invasive ventilation in acute hypercapnic respiratory failure","volume":"24","author":"Comellini","year":"2019","journal-title":"Respirology"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"S61","DOI":"10.5005\/jp-journals-10071-G23186","article-title":"ISCCM Guidelines for the Use of Non-invasive Ventilation in Acute Respiratory Failure in Adult ICUs","volume":"24","author":"Gupta","year":"2019","journal-title":"Indian J. Crit. Care Med."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"133","DOI":"10.54361\/LJMR.19.2.17","article-title":"The Role of Noninvasive Ventilation in Managing Respiratory Failure: A Literature Review","volume":"19","author":"Alweshahi","year":"2025","journal-title":"Libyan J. Med. Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1161\/JAHA.116.003607","article-title":"Repolarization Heterogeneity: Beyond the QT Interval","volume":"5","author":"Prenner","year":"2016","journal-title":"J. Am. Heart Assoc."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"e18750362295563","DOI":"10.2174\/0118750362295563240620111209","article-title":"The Clinical Relevance of ECG Parameters in the Prediction of Cardiac Mortality: A Comprehensive Review","volume":"17","author":"Singh","year":"2024","journal-title":"Open Bioinform. J."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"551","DOI":"10.1016\/j.jdiacomp.2016.12.001","article-title":"A large frontal QRS-T angle is a strong predictor of the long-term risk of myocardial infarction and all-cause mortality in the diabetic population","volume":"31","author":"May","year":"2017","journal-title":"J. Diabetes Its Complicat."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1016\/j.jelectrocard.2017.02.008","article-title":"T wave axis deviation and QRS-T angle\u2013Controversial indicators of incident coronary heart events","volume":"50","author":"Dilaveris","year":"2017","journal-title":"J. Electrocardiol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"12388","DOI":"10.1111\/anec.12388","article-title":"Frontal QRS-T Angle and the Risk of Atrial Fibrillation in the Elderly","volume":"22","author":"Jogu","year":"2017","journal-title":"Ann. Noninvasive Electrocardiol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"534","DOI":"10.1111\/anec.12206","article-title":"QRS-T Angle: A Review","volume":"19","author":"Oehler","year":"2014","journal-title":"Ann. Noninvasive Electrocardiol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/j.hrthm.2004.10.040","article-title":"Spatial QRS-T angle predicts cardiac death in a clinical population","volume":"2","author":"Yamazaki","year":"2005","journal-title":"Heart Rhythm"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1880","DOI":"10.1016\/j.amjcard.2013.08.017","article-title":"Prognostic Value of Frontal QRS-T Angle in Patients Without Clinical Evidence of Cardiovascular Disease (from the Multi-Ethnic Study of Atherosclerosis)","volume":"112","author":"Walsh","year":"2013","journal-title":"Am. J. Cardiol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1571332","DOI":"10.1080\/20018525.2019.1571332","article-title":"NIV for acute respiratory failure in COPD: High in-hospital mortality is determined by patient selection","volume":"6","author":"Hedsund","year":"2019","journal-title":"Eur. Clin. Respir. J."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1585","DOI":"10.1164\/ajrccm.160.5.9903015","article-title":"Acute Respiratory Failure in Patients with Severe Community-acquired Pneumonia: A Prospective Randomized Evaluation of Noninvasive Ventilation","volume":"160","author":"Confalonieri","year":"1999","journal-title":"Am. J. Respir. Crit. Care Med."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/18\/7066\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T14:47:05Z","timestamp":1789138025000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/18\/7066"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,11]]},"references-count":36,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["jcm15187066"],"URL":"https:\/\/doi.org\/10.3390\/jcm15187066","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,11]]}}}