Admission ischemic ECG patterns and long-term outcomes in Takotsubo syndrome: A Nationwide Danish cohort study.

BACKGROUND: Takotsubo syndrome (TTS) is a reversible acute heart failure syndrome. Electrocardiographic (ECG) abnormalities are common at presentation and may reflect disease severity. We aimed to determine whether distinct ischemic ECG patterns at admission identify TTS patients at higher risk of mortality. METHODS: In this nationwide, register-based cohort study, we included patients with a first-time TTS diagnosis between 2008 and 2021 and an ECG recorded within 24 h of admission. Follow-up continued until death or the end of follow-up (October 25th, 2025), whichever occurred first. Patients were stratified according to ECG pattern: ST-segment elevation, ST-segment depression, T-wave inversion, left or right bundle branch block (LBBB/RBBB), or no repolarization or conduction abnormalities. The primary outcome was 1-year all-cause mortality; cardiovascular death was secondary. Multivariable Cox regression was adjusted for prespecified clinical covariates. RESULTS: We included 1244 patients (mean age 70.8 years; 89.1% women). One-year mortality was highest with ST-segment elevation (15.9%), followed by LBBB or RBBB (12.5%) and no repolarization or conduction abnormalities (8.3%). Mortality was lowest with T-wave inversion (7.4%) and ST-segment depression (5.3%). ST-segment elevation was independently associated with all-cause mortality (HR 1.32, 95% CI 1.04-1.66), whereas ST-segment depression, T-wave inversion, and LBBB or RBBB were not. Cardiovascular death was higher with ST-segment elevation than without (25.0% vs 18.8%), but adjusted risk was not significantly different (HR 1.39, 95% CI 0.83-2.30). CONCLUSIONS: ST-segment elevation on admission ECG identifies TTS patients at higher risk of all-cause mortality and may support early risk stratification.