ABSTRACT NUMBER: ESOC2026A1319 ADMISSION QTC-INTERVAL ON STANDARD 12-LEAD ECG IS ASSOCIATED WITH CLINICAL OUTCOMES OVER 24 MONTHS AFTER ISCHEMIC STROKE OR TRANSIENT ISCHEMIC ATTACK

Abstract Background and aims We evaluated the association between admission Bazett-corrected QT-interval (QTc) on 12-lead ECGs and clinical outcomes after acute ischemic stroke or transient ischemic attack (TIA). Methods MonDAFIS randomised patients with ischemic stroke/TIA without known atrial fibrillation to prolonged in-hospital Holter-ECG (N=3,465). In this post-hoc analysis of the intervention group (manual caliper QT-interval measurement) QTc on the routine 12-lead ECG on admission was related to MACCE (recurrent stroke, myocardial infarction, major bleeding, or death), recurrent stroke, and mortality over 24 months. Patients with QRS>120 ms due to left bundle branch block or nonspecific intraventricular conduction delay were excluded. Multivariable Cox regression models were adjusted for age, sex, stroke severity (NIHSS>5), and cardiovascular comorbidities. Results QT-interval assessment was feasible in 1,369/1,714 patients. Median QTc was 408 ms (IQR 389-428) in men and 416 ms (IQR 400-434) in women. Prolonged QTc (≥ 450 ms in men; ≥ 460 ms in women) occurred in 107/1,369 patients (7.8%). Per 1 standard deviation increase, z-standardised QTc was associated with MACCE (HR 1.40, 95%CI 1.14-1.72, p=0.001), mortality (HR 1.66, 95%CI 1.16-2.36, p=0.001), and recurrent stroke (HR 1.38, 95%CI 1.07-1.77, p=0.012). When analysed dichotomously, prolonged QTc was associated with mortality (HR 2.68, 95%CI 1.33-5.40, p=0.006), but not with MACCE or recurrent stroke. Conclusions Higher QTc was associated with increased risk of MACCE, mortality, and recurrent stroke after ischemic stroke/TIA. The recurrent stroke association was evident for continuous QTc but not for established cut-offs. QTc may help identify patients who could benefit from intensified follow-up. Conflict of interest This work was supported by an unrestricted research grant from Bayer Vital GmbH, Germany. MCO, MB, ST, FS and CK do not have potential conflicts of interests outside the submitted work. ME reports grants from Bayer and fees paid to the Charité from Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers-Squibb, Covidien, Daiichi Sankyo, Glaxo Smith Kline, Novartis, Pfizer and Sanofi,all outside the submitted work. KGH reports speaker's honoraria, consulting fees, lecture honoraria and/or study grants from Abbott, Amarin; AstraZeneca, Bayer Healthcare, Biotronik, Boehringer Ingelheim, Boston Scientific, Bristol-Myers Squibb, Daiichi Sankyo, Edwards Lifesciences, Medronic, Novartis, Pfizer, Portola, Premier Research, Sanofi, SUN Pharma, and W.L. Gore and Associates. RBS has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under the grant agreement No. 648131, from the European Union’s Horizon 2020 research and innovation programme under the grant agreement No. 847770 (AFFECT-EU), from the European Union’s Horizon Europe research and innovation programme under the grant agreement ID: 101095480 and German Center for Cardiovascular Research (DZHK e.V.) (81Z1710103 and 81Z0710114); German Ministry of Research and Education (BMBF 01ZX1408A) and ERACoSysMed3 (031L0239). Wolfgang Seefried project funding German Heart Foundation. RBS has received lecture fees and advisory board fees from BMS/Pfizer and Bayer outside this work.