Acute hospital management

1. Immediate stabilization
   • ABCs, cardiac monitor/defibrillator access, IV access.
   • 12-lead ECG within 10 minutes and repeat if initially nondiagnostic.
   • Serial high-sensitivity troponins, CBC, renal function, glucose, electrolytes, coagulation tests.
   • Oxygen only if hypoxemic, respiratory distress, or shock.
   • Assess for arrhythmia, heart failure, cardiogenic shock, mechanical complications, and bleeding risk.
2. Initial medications, tailored to contraindications
   • Aspirin promptly, unless true allergy or active major bleeding.
   • Add a P2Y12 inhibitor and give parenteral anticoagulation as part of ACS treatment, particularly when PCI is planned.
   • Nitroglycerin for ongoing ischemic pain if blood pressure is adequate. Avoid with hypotension, suspected right-ventricular infarction, or recent phosphodiesterase-5 inhibitor use.
   • Opioid analgesia only for pain that persists despite anti-ischemic measures.
   • Start a high-intensity statin early.
   • Avoid routine NSAIDs other than aspirin.
3. Reperfusion or invasive management
   • STEMI or equivalent with ongoing ischemia: urgent primary PCI is preferred. If timely PCI is not feasible and there are no contraindications, fibrinolysis may be considered in an appropriate early-presenting patient, followed by transfer to a PCI-capable center.
   • NSTEMI: do not give fibrinolysis. Risk-stratify using clinical instability, ECG changes, troponin rise, GRACE risk, heart failure, or recurrent pain. High-risk patients need early invasive coronary angiography and revascularization where indicated.
4. Treat complications
   • Pulmonary edema/heart failure: diuretics, vasodilators if not hypotensive, ventilatory support as needed.
   • Cardiogenic shock: urgent revascularization, vasopressor/inotrope support, critical-care management, and selective mechanical circulatory support.
   • Bradyarrhythmias or VT/VF: ACLS-based management, defibrillation for unstable VT/VF.
   • Obtain echocardiography to assess LV function and mechanical complications.

Secondary prevention before discharge

• Dual antiplatelet therapy is generally continued for about 12 months after ACS if bleeding risk is not high, then individualized.
• Continue high-intensity statin and achieve aggressive LDL-C lowering.
• Start a beta-blocker if appropriate, especially with reduced LV function, while avoiding it in shock, severe bradycardia, or decompensated heart failure.
• Use an ACE inhibitor/ARB for LVEF ≤40%, anterior MI, heart failure, diabetes, hypertension, or CKD; add a mineralocorticoid receptor antagonist when indicated and renal function/potassium permit.
• Smoking cessation, cardiac rehabilitation, diabetes and blood-pressure control, exercise/diet counseling, vaccination as appropriate, and medication adherence.
• Arrange cardiology follow-up and give clear return precautions.

Latest ACS / MI management guidelines

1. Main current US guideline

• Aspirin plus an oral P2Y12 inhibitor as default DAPT, generally for at least 12 months if bleeding risk is not high.
• High-intensity statin for all ACS patients.
• Addition of non-statin lipid lowering therapy when LDL-C remains ≥70 mg/dL despite maximally tolerated statin therapy.
• Radial rather than femoral access for PCI when feasible.
• Intravascular imaging guidance for PCI.
• Complete revascularization in appropriate STEMI and NSTE-ACS patients.
• Immediate revascularization for ACS-related cardiogenic shock, with microaxial flow-pump support only in selected cases.
• Cardiac rehabilitation and lipid reassessment 4-8 weeks after starting or changing lipid-lowering therapy.

2. Main current European guideline

3. Newest MI definition, not a management guideline

Practical takeaway

1. 2025 ACC/AHA/ACEP/NAEMSP/SCAI ACS Guideline for the most recent comprehensive US recommendations.
2. 2023 ESC ACS Guideline for current European recommendations.
3. 2026 Fifth Universal Definition of MI for diagnostic classification.

1. United States: 2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for Management of Acute Coronary Syndromes
   Published 27 February 2025. This is the newest comprehensive US guideline for type 1 MI, including both STEMI and NSTEMI. It covers initial assessment, antithrombotic therapy, PCI/revascularization, cardiogenic shock, discharge planning, and secondary prevention. The ACC ACS guideline hub provides the full guideline, pocket resources, and summary materials.
   • Practice-guideline companion: Kumbhani et al. (2025), 2025 Acute Coronary Syndromes Guideline-at-a-Glance, JACC. PMID: 40013745.
2. Europe: 2023 ESC Guidelines for the Management of Acute Coronary Syndromes
   This remains the current comprehensive ESC ACS guideline as of October 2026. It combines STEMI and NSTE-ACS into one document and addresses triage, diagnosis, invasive strategies, antithrombotic treatment, cardiogenic shock, multivessel disease, MINOCA, complications, and secondary prevention. Access the ESC ACS guideline page.
3. Diagnostic classification: Fifth Universal Definition of Myocardial Infarction, 2026
   This is the newest multinational document for defining and classifying MI, including type 1, type 2, and procedure-related MI. It is a diagnostic-definition document, not a replacement for ACS treatment guidelines. The ESC acute cardiac care resource lists it with current ACS guidance.

High-yield changes emphasized in the 2025 US ACS guideline

• Default DAPT: aspirin plus an oral P2Y12 inhibitor for at least 12 months in ACS patients without high bleeding risk.
• High-intensity statin for all ACS patients, with added non-statin therapy if LDL-C remains ≥70 mg/dL despite maximally tolerated statin.
• Prefer radial access for PCI when feasible.
• Intravascular imaging-guided PCI is strongly recommended.
• Aim for appropriate complete revascularization in STEMI and NSTE-ACS.
• Prompt revascularization in ACS-related cardiogenic shock; temporary microaxial flow-pump support is reserved for selected patients.
• Refer to cardiac rehabilitation and reassess lipids 4-8 weeks after starting or adjusting therapy.