What are the initial steps in a STEMI (ST-Elevation Myocardial Infarction) workup?

Initial Steps in STEMI Workup

The immediate goal in STEMI workup is rapid diagnosis followed by prompt reperfusion therapy, with a door-to-balloon time of <90 minutes for primary PCI or door-to-needle time of <30 minutes for fibrinolysis when PCI is not available within 120 minutes of first medical contact. 1

Immediate Assessment and Diagnosis

1. ECG acquisition and interpretation:

   • Obtain a 12-lead ECG within 10 minutes of patient arrival or first medical contact 1
   • Look for ST-segment elevation ≥1 mm in two or more contiguous leads, or new left bundle branch block 1
   • Consider right-sided ECG if inferior or RV STEMI is suspected 1

2. Initial medication administration:

   • Administer aspirin 162-325 mg (chewed or IV if unable to swallow) immediately 1
   • Administer a P2Y12 inhibitor (preferably prasugrel or ticagrelor, or clopidogrel if these are unavailable) 1, 2
   • Start anticoagulation with unfractionated heparin (enoxaparin or bivalirudin may be alternatives) 1

3. Reperfusion strategy determination:

   • Assess time from symptom onset 1
   • Determine time required for transfer to PCI-capable facility 1
   • Evaluate risk factors for bleeding with fibrinolysis 1
   • Assess for cardiogenic shock or severe heart failure 1

Reperfusion Decision Algorithm

Primary PCI Strategy (Preferred)

• If PCI can be performed within 90 minutes of first medical contact (FMC) 1
• For patients with cardiogenic shock or severe heart failure regardless of time delay 1
• For patients with contraindications to fibrinolysis 1
• Transport directly to catheterization laboratory, bypassing emergency department 1

Fibrinolysis Strategy

• If primary PCI cannot be performed within 120 minutes of FMC (or 90 minutes in patients <75 years with large anterior infarction and recent symptom onset) 1
• Administer fibrinolytic therapy within 30 minutes of hospital arrival 1
• Use a fibrin-specific agent (tenecteplase, alteplase, or reteplase) 1
• Transfer to a PCI-capable center immediately after fibrinolysis 1
• Plan for coronary angiography within 2-24 hours after successful fibrinolysis 1

Additional Initial Management

1. Hemodynamic monitoring:

   • Continuous ECG monitoring for arrhythmias
   • Regular blood pressure monitoring
   • Oxygen saturation monitoring

2. Laboratory studies:

   • Cardiac biomarkers (troponin, CK-MB)
   • Complete blood count
   • Basic metabolic panel
   • Coagulation profile
   • Lipid profile

3. Imaging:

   • Echocardiography to assess left ventricular function and detect mechanical complications 1
   • Chest radiography

Common Pitfalls to Avoid

1. Delayed recognition and treatment:

   • Failure to obtain ECG within 10 minutes of arrival
   • Delays in activating the catheterization laboratory
   • Unnecessary transfers between departments

2. Inappropriate reperfusion strategy selection:

   • Choosing fibrinolysis when timely PCI is available
   • Delaying fibrinolysis when timely PCI is not available

3. Overlooking high-risk features:

   • Missing signs of cardiogenic shock
   • Failing to identify right ventricular involvement in inferior MIs
   • Not recognizing mechanical complications

4. Medication errors:

   • Administering fibrinolytics to patients with contraindications
   • Failing to give dual antiplatelet therapy before PCI
   • Using fondaparinux for primary PCI (contraindicated) 1

The most recent European Society of Cardiology guidelines emphasize that time is critical in STEMI management, and all efforts must be made to minimize delays between symptom onset and reperfusion therapy 1. The establishment of regional STEMI networks with clear protocols for emergency medical services and hospitals is essential for optimal patient outcomes 1.