• Objectives: The primary objective of this study is to evaluate the safety of an early discharge strategy in patients with low risk ST-elevation myocardial infarction (STEMI), treated with primary percutaneous coronary intervention (PPCI), compared to a conventional strategy.
• Methodology: Unicentric, randomized, controlled, non-inferiority and open label clinical trial. The investigators will compare an early discharge strategy (≤72 hours) with a conventional strategy (discharge according to treating physician's criterion). Inclusion criteria will be: low risk (Zwolle risk score ≤3) STEMI treated with PPCI within 24 hours from symptoms onset. Exclusion criteria will be: arrhythmias (ventricular tachycardia or fibrillation, asystole, pulseless electrical activity, advanced atrio-ventricular block), mechanical complications (cardiac tamponade, free-wall or septal rupture, acute mitral regurgitation, pericarditis), severe or moderate bleeding (according to the GUSTO criteria), complications related to vascular access of the procedure, acute kidney failure, infection, heart failure. Sample size will be 1558 subjects (n=779 per group). The investigators will study demographic, clinical, biochemical, echocardiographic and angiographic variables. The primary endpoint will be a composite of death, reinfarction, new angina, heart failure, ventricular arrhythmias, stroke and severe bleeding. The secondary endpoint will include each of the items of the primary endpoint and quality of life and functional capacity questionnaire SF-36. Finally, the investigators will analyze the degree of compliance with the European Society of Cardiology guidelines on STEMI and the rate of hospitalization-related complications. Follow up will be at 30 days.

Inclusion Criteria:

• low risk (Zwolle risk score ≤3) STEMI treated with PPCI within 24 hours from symptoms onset
• Informed consent

Exclusion Criteria:

• arrhythmias (ventricular tachycardia or fibrillation, asystole, pulseless electrical activity, advanced atrio-ventricular block)
• mechanical complications (cardiac tamponade, free-wall or septal rupture, acute mitral regurgitation, pericarditis)
• severe or moderate bleeding (according to the GUSTO criteria)
• complications related to vascular access of the procedure
• acute kidney failure
• infection
• heart failure