Association between pre‐operative prolonged corrected QT interval and all‐cause mortality after non‐cardiac surgery

• Published in: Acta Anaesthesiologica Scandinavica
• Main Authors: Johannsdottir, Helena Xiang, Gudmundsdottir, Ingibjorg Jona, Karason, Sigurbergur, Sigurdsson, Martin Ingi
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2022
• Subjects: Iceland
• Online Access: http://dx.doi.org/10.1111/aas.14178; https://onlinelibrary.wiley.com/doi/pdf/10.1111/aas.14178; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/aas.14178

Abstract Background Prolonged corrected QT interval (QTc) has been linked to risk of arrhythmias and mortality in the general population. Pre‐operative electrocardiography is often obtained for patient‐and procedural cardiovascular risk assessment. The aim of this study was to investigate the association of pre‐operative QTc and all‐cause mortality in a non‐cardiac surgical cohort. Methods A retrospective study of all patients over 18 years undergoing non‐cardiac surgery at Landspitali–the National University Hospital in Iceland between 2 January 2005 to 31 December 2015, with follow‐up through 20 May 2016. Patients were separated into five categories according to their pre‐operative QTc interval ≤ 379, 380–439 (reference group), 440–479, 480–519 and ≥520 ms. Primary outcome was long‐term mortality and secondary outcome was 30‐day mortality. Results A total of 10,209 surgeries for 10,209 individuals were included. The median follow‐up for mortality was 2691 days (interquartile range [IQR] 1620–3705 days). Patients with longer QTc interval had a higher comorbidity burden, were more likely to undergo emergency surgery and were often prescribed cardiac medications. After adjustment for confounding variables, the hazard ratio (HR) for long‐term mortality compared with reference (QTc 380‐439 ms) was 0.85 [CI: 0.66–1.09] for QTc ≤379, 1.08 [CI: 0.99–1.17] for QTc 440–479 ms, 1.26 [CI: 1.10–1.43] for QTc between 480 and 519 ms and 0.97 [CI: 0.78–1.21] for QTc ≥520 ms. When compared with reference, only patients with QTc interval between 480 and 519 ms had higher odds ratio for 30‐day mortality as odds ratio for other groups were following; 1.12 [CI: 0.18–3.8] for ≤379 ms, 1.03 [CI: 0.70–1.51] for QTc 440‐479 ms, 1.64 [CI: 1.02–2.60] for QTc 480‐519 ms and 0.98 [0.44–2.06] for QTc ≥520 ms. Conclusion Pre‐operative QTc between 480 and 519 ms is associated with both higher long‐term and 30‐day mortality after non‐cardiac surgery. The results suggest that this could reflect an underlying cardiovascular risk.