BACKGROUND: Takotsubo syndrome (TS) and STEMI with timely reperfusion are both characterized by reversible acute myocardial dysfunction, often referred to as myocardial stunning. The natural course of cardiac functional recovery is incompletely understood in TS and STEMI. The aim of this study was to prospectively compare changes in cardiac function over the acute and subacute phases in women with TS versus anterior STEMI. METHODS: The Stunning in Takotsubo versus Acute Myocardial Infarction (STAMI) study prospectively enrolled 61 women with TS and 41 women with STEMI. Echocardiography and blood sampling was performed within 4 h of admission and at 1, 2, 3, 7, 14, and 30 days after admission. The primary outcome was the proportion of reversible left ventricular akinesia (defined as extent of akinesia at baseline versus at 30 days) that resolved by 72 h. Secondary outcomes included LVEF, GLS, and TAPSE. Mixed effects linear regression or mixed effects tobit models with random intercepts were used to model echocardiographic parameters over time. RESULTS: At 72 h 40.4% [95% CI 30.1%, 50.1%] of the reversible akinesia had resolved in women with TS, versus 54.7% [95% CI 38.3%, 72.0%] for STEMI (difference 14.3% [95% CI - 4.6%, 34.3%]). Time-course of recovery of LVEF and GLS was also similar in TS and STEMI. TAPSE was reduced in TS but normal in STEMI
and recovered in a similar timeframe as the left ventricular indices. In both TS and STEMI, considerable recovery of cardiac function occurred after 7 days. CONCLUSIONS: The time course of recovery of cardiac function is similar in TS and STEMI. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT04448639, https://clinicaltrials.gov/study/NCT04448639 .