Management of ST-Elevation Myocardial Infarction (STEMI)

Initial Assessment and Management

The American College of Cardiology recommends immediately administering 162-325 mg of non-enteric coated aspirin to all STEMI patients upon first medical contact 1
A 12-lead ECG should be performed and shown to an experienced emergency physician within 10 minutes of emergency department arrival for all patients with chest discomfort or symptoms suggestive of STEMI 3
If the initial ECG is not diagnostic but clinical suspicion remains high, serial ECGs at 5-10 minute intervals or continuous 12-lead ST-segment monitoring should be performed 3
In patients with inferior STEMI, right-sided ECG leads should be obtained to screen for right ventricular infarction 3
Administer supplemental oxygen only to patients with arterial oxygen desaturation or respiratory distress 1, 2
Provide morphine sulfate for patients with ongoing ischemic pain or pulmonary congestion 1, 2
Initiate oral beta-blocker therapy promptly in patients without contraindications 1, 2

Every community should have a written protocol guiding EMS personnel in determining where to take STEMI patients 4
The critical decision point is whether primary PCI can be performed within 120 minutes of first medical contact 5, 2
For patients presenting within 12 hours of symptom onset without contraindications, immediate reperfusion therapy is indicated 5
For high-risk patients presenting within 2 hours of symptom onset, the PCI-related delay should not exceed 90 minutes 4

Administer dual antiplatelet therapy before PCI, including aspirin and a P2Y12 inhibitor, as early as possible 1, 2
For patients receiving stents, dual antiplatelet therapy should be continued for at least 12 months 2

If primary PCI cannot be performed within 120 minutes of first medical contact, administer fibrinolytic therapy within 30 minutes of hospital arrival 5, 2

Patients with cardiogenic shock and age <75 years should be immediately transferred to facilities capable of cardiac catheterization and rapid revascularization if it can be performed within 18 hours of shock onset 4
For patients ≥75 years with cardiogenic shock, emergency revascularization should still be considered, especially in those with good prior functional status 2
Patients with STEMI who have contraindications to fibrinolytic therapy should be transferred promptly to PCI-capable facilities 4

Initiate ACE inhibitors within 24 hours in patients with anterior STEMI, heart failure, or ejection fraction ≤0.40 1, 2
Start high-intensity statin therapy in all STEMI patients without contraindications 1
Continue dual antiplatelet therapy with aspirin and a P2Y12 inhibitor for at least 12 months in patients receiving stents 2
Patients who routinely took nonsteroidal anti-inflammatory drugs before STEMI should discontinue these agents due to increased risks of adverse outcomes 5

For cardiogenic shock, emergency revascularization is recommended regardless of time delay from MI onset 1, 2
Intra-aortic balloon counterpulsation is useful for patients with cardiogenic shock not quickly stabilized with pharmacological therapy 2
Ventricular septal rupture, free wall rupture, and papillary muscle rupture require urgent surgical consultation 2

Do not delay reperfusion therapy to wait for cardiac biomarker results; initiate treatment based on clinical presentation and ECG findings 3
Avoid immediate-release nifedipine in STEMI patients due to reflex sympathetic activation, tachycardia, and hypotension 2
Do not administer beta-blockers or calcium channel blockers to patients with frank cardiac failure, pulmonary congestion, or signs of low-output state 1
Serial biomarker measurements should not be relied on to diagnose reinfarction within the first 18 hours after STEMI onset 3