What is the management approach for a patient presenting with ST-Elevation Myocardial Infarction (STEMI) symptoms?

Management of ST-Elevation Myocardial Infarction (STEMI)

Immediate aspirin administration (162-325 mg chewed) and rapid reperfusion therapy—either primary PCI within 90-120 minutes or fibrinolysis within 30 minutes of first medical contact—represent the cornerstone of STEMI management and directly reduce mortality. 1, 2

Initial Recognition and Diagnosis

Obtain a 12-lead ECG within 10 minutes of first medical contact to identify ST-segment elevation >0.1 mV in at least two contiguous precordial or adjacent limb leads, new left bundle branch block, or true posterior MI. 1, 2

• Initiate continuous ECG monitoring with defibrillator capacity immediately upon suspicion of STEMI. 1, 2
• Do NOT routinely administer oxygen unless oxygen saturation is <90%. 1, 2
• Administer morphine sulfate for pain relief and pulmonary congestion. 1

Reperfusion Strategy Selection

The choice between primary PCI and fibrinolysis depends entirely on time to treatment:

Primary PCI (Preferred Strategy)

Primary PCI is the preferred reperfusion method when it can be performed within 120 minutes of STEMI diagnosis by an experienced team (>75 primary PCI cases/year per operator, >36 cases/year per team). 1, 2

• Transfer patients directly to the catheterization laboratory, bypassing the emergency department entirely. 1, 2
• The goal is balloon inflation within 90 minutes of first medical contact. 1
• PCI-capable centers must provide 24/7 service without delay. 1, 2

Primary PCI is strongly preferred in these specific situations: 1, 2

• Cardiogenic shock (Killip class III or greater)
• Contraindications to fibrinolysis
• Diagnosis of STEMI is uncertain
• High-risk patients requiring emergency revascularization

Fibrinolytic Therapy

If primary PCI cannot be performed within 120 minutes of diagnosis, administer fibrinolysis within 30 minutes of first medical contact in patients presenting within 12 hours of symptom onset. 1, 2

• Use a fibrin-specific agent: tenecteplase (preferred for single bolus), alteplase, or reteplase. 1, 2, 3
• Tenecteplase dosing: 0.53 mg/kg (30-50 mg) as single IV bolus; reduce dose by 50% in patients ≥75 years to reduce stroke risk. 2
• Prehospital fibrinolysis is reasonable when EMS systems are appropriately trained and staffed. 1

Fibrinolysis is generally preferred when: 1

• Early presentation (<3 hours from symptom onset) and PCI not readily available
• Skilled PCI facility cannot be accessed within the required timeframe

Antithrombotic Therapy

For Primary PCI Patients

Administer aspirin 150-325 mg orally (or 250-500 mg IV if unable to swallow) immediately. 1, 2

Give a potent P2Y12 inhibitor before or at the time of PCI: 1, 2

• Prasugrel or ticagrelor (preferred)
• Clopidogrel only if prasugrel/ticagrelor unavailable

Anticoagulation during PCI: 1, 2

• Unfractionated heparin: 100 U/kg IV bolus (60 U/kg if using GPIIb/IIIa inhibitors)
• Enoxaparin or bivalirudin are acceptable alternatives
• Do NOT use fondaparinux for primary PCI

For Fibrinolysis Patients

Administer oral or IV aspirin plus clopidogrel. 1, 2, 3

Provide anticoagulation with enoxaparin (preferred) or unfractionated heparin until revascularization or for duration of hospital stay (up to 8 days). 1, 2, 3

Special Populations and Complications

Cardiogenic Shock

Transport immediately to a facility capable of cardiac catheterization and rapid revascularization (PCI and CABG). 1

• Perform rapid volume loading with IV infusion in patients without volume overload. 1
• Insert intra-aortic balloon pump for patients not responding to other interventions. 1
• Early revascularization (PCI or CABG) is recommended for patients <75 years who develop shock within 36 hours of MI, when performed within 18 hours of shock onset. 1

Cardiac Arrest with STEMI

Pursue primary PCI strategy in patients with resuscitated cardiac arrest and ECG showing STEMI. 1, 2, 3

• Initiate targeted temperature management early in patients who remain unconscious after resuscitation. 1, 3
• Do NOT use prehospital cooling with rapid infusion of large volumes of cold IV fluid. 1, 3

Pulmonary Congestion/Heart Failure

Administer oxygen to maintain saturation >90%, morphine sulfate, and ACE inhibitors (starting with low-dose short-acting agent like captopril 1-6.25 mg) unless systolic BP <100 mmHg. 1

• Do NOT give beta-blockers or calcium channel blockers acutely to patients with frank cardiac failure. 1

In-Hospital Management

Continue dual antiplatelet therapy (aspirin plus P2Y12 inhibitor) for 12 months. 1, 2

• Duration varies by stent type: no stent (14 days), bare-metal stent (≥1 month, ideally 1 year), drug-eluting stent (1 year). 1

Initiate high-intensity statin therapy as early as possible. 2, 4

Start beta-blockers orally in patients with heart failure and/or LVEF <40% unless contraindicated. 2, 4

Begin ACE inhibitors within 24 hours in patients with heart failure, LV systolic dysfunction, diabetes, or anterior infarct. 2, 4

Perform routine echocardiography during hospitalization to assess LV/RV function, detect mechanical complications, and exclude LV thrombus. 2, 4

Critical Pitfalls to Avoid

Discontinued NSAIDs (except aspirin) immediately—they increase mortality, reinfarction, hypertension, heart failure, and myocardial rupture risk. 1

Do NOT pursue facilitated PCI strategy (full-dose fibrinolysis followed by PCI)—this approach may be harmful. 1

Do NOT perform routine PCI of an occluded infarct-related artery >48 hours after STEMI onset in asymptomatic patients. 1, 2

Recognize atypical presentations, especially in women, elderly, and diabetic patients, which commonly lead to delayed diagnosis and treatment. 2