Hemorrhagic Myocardial Infarction and Intramyocardial Hemorrhage: From Microvascular Damage to Emerging Therapeutic Targets.

Intramyocardial hemorrhage (IMH) is a severe form of post-ischemic microvascular injury that may occur after myocardial infarction, particularly in the setting of extensive ischemia and reperfusion. IMH is closely related to microvascular obstruction (MVO), larger infarct size, impaired left-ventricular (LV) function, and adverse clinical outcomes. Cardiovascular magnetic resonance (CMR), especially susceptibility-sensitive techniques such as T2* or R2* mapping, enables in vivo detection of hemorrhagic microvascular injury and may refine post-MI risk stratification. Mechanistic and translational studies suggest that erythrocyte degradation and infarct-core iron deposition may contribute to persistent inflammation, maladaptive healing, adverse remodeling, and possibly arrhythmogenic substrate formation. However, most clinical evidence remains observational, and IMH-guided management has not yet been prospectively validated. This narrative review summarizes current evidence on the pathophysiology, imaging diagnosis, prognostic significance, and emerging therapeutic implications of IMH, while highlighting unresolved questions regarding standardized imaging, clinical implementation, and future phenotype-directed therapies.