Temporal and Mechanistic Insights into Stress-Induced and Ischemic Cardiomyopathy - The STAMI study

Abstract

Background: Myocardial stunning is marked by transient yet prolonged left ventricular (LV) dysfunction despite restored coronary perfusion. It is a central feature of two clinically overlapping but mechanistically distinct conditions: ST-elevation myocardial infarction (STEMI) and Takotsubo syndrome (TS). Despite similar presentations, differences in recovery, myocardial mechanics, and biological responses remain incompletely understood. Methods: The Stunning in Takotsubo versus Acute Myocardial Infarction (STAMI) study prospectively enrolled patients with STEMI or TS. Serial echocardiography and biomarker sampling were performed at admission and on days 1, 2, 3, 7, 14, and 30. Six sub-studies assessed quantitative indices of myocardial dysfunction, myocardial strain, LV thrombus formation, and plasma proteomic profiles. Results: Proportion akinesia (PrA) and akinesia/hypokinesia (PrAH) were validated as reproducible measures of wall motion abnormality. Both TS and anterior STEMI showed marked initial impairment followed by substantial recovery beyond day 7, with similar overall trajectories. Women exhibited greater recovery than men after anterior STEMI. Myocardial strain was severely impaired acutely in both conditions, with more diffuse dysfunction in TS. LV thrombus occurred exclusively in STEMI and was associated with reduced LV function and higher troponin levels. Plasma proteomics revealed distinct signatures, with STEMI characterized by inflammatory and complement activation, and TS by a more regulated stress-response profile. Conclusion: These findings highlight myocardial stunning as a dynamic and biologically active process, providing insight into the mechanisms of injury, recovery, and potential therapeutic targets.