This multicenter registry includes patients with a first ST-segment elevation myocardial infarction (STEMI) who underwent cardiac magnetic resonance (CMR) imaging during the acute phase and follow-up. The registry is designed to identify clinical and CMR-derived predictors of adverse ventricular remodeling and major adverse cardiac events (MACE). CMR provides accurate and reproducible assessment of infarct size, left ventricular function, microvascular obstruction, and tissue characteristics, enabling detailed prognostic modeling.

Adverse left ventricular remodeling after STEMI is a key determinant of long-term morbidity and mortality. Although primary PCI and guideline-directed therapies have improved outcomes, 10-15% of patients still develop adverse remodeling and heart failure. CMR enables precise measurement of infarct size, left ventricular volumes, ejection fraction, microvascular obstruction, and tissue parameters (T1, extracellular volume), which may enhance risk stratification compared with other imaging techniques.

The registry is based on harmonized clinical and imaging datasets from three experienced centers in Spain, forming a large repository of standardized variables. This structure facilitates the identification of predictors of infarct size, ventricular remodeling, and major adverse cardiac events (MACE), and provides a framework for the development of improved prognostic models and the exploration of potential therapeutic targets.

Inclusion Criteria:

• Age ≥ 18 years
• First STEMI evaluated within the first 24 hours of symptom onset
• At least one CMR performed during the acute phase
• Signed informed consent (for prospective patients) or previous consent (for retrospective inclusion).

Exclusion Criteria:

• Severe renal failure (GFR < 30 ml/min)
• STEMI > 24 hours after symptom onset
• Contraindications to CMR (e.g., claustrophobia, hemodynamic instability, non-MR-compatible devices, vascular clips)
• Pregnancy or breastfeeding.

The study population consists of patients admitted with a first ST-segment elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI) and were evaluated by cardiac magnetic resonance (CMR) both in the acute phase and during follow-up. The study is conducted in tertiary academic hospitals with well-established CMR programs, ensuring standardized imaging protocols and high-quality data acquisition. Participating centers include the Hospital Clínic de Barcelona, the Hospital Clínico Universitario de Valencia, and the Hospital Universitari Vall d'Hebron, all located in Spain.

De-identified individual participant data (IPD) will not be shared because data sharing is not planned for this study.