ST-elevation myocardial infarction (STEMI)
ST-elevation myocardial infarction is acute transmural myocardial ischemia from complete coronary occlusion, diagnosed by ischemic symptoms with diagnostic ST-segment elevation and a rising troponin. It is a time-critical emergency in which immediate reperfusion, primary PCI within 90 minutes or fibrinolysis when PCI is unavailable, plus antiplatelet and anticoagulant therapy, determines survival.
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What this article covers
- Overview
Definition: ST-elevation myocardial infarction (STEMI) is acute myocardial injury from complete, sustained occlusion of a coronary artery, producing transmural ischemia.
- Epidemiology
A leading cause of death: a major manifestation of coronary artery disease.
- Risk factors
Established atherosclerotic risk factors: smoking, diabetes, hypertension, dyslipidemia, and family history of premature coronary disease.
- Pathophysiology
Plaque rupture and thrombosis: a vulnerable atherosclerotic plaque ruptures, exposing thrombogenic material and forming an occlusive platelet-fibrin thrombus.
- Clinical features
Chest pain: severe, pressure-like substernal pain, often radiating to the arm or jaw, lasting more than 20 minutes and not relieved by rest.
- Differential diagnosis
Aortic dissection: tearing pain radiating to the back with pulse or blood-pressure differential; reperfusion drugs are dangerous (aortic dissection).
- Diagnosis
Establish with the Fourth Universal Definition of MI plus STEMI ECG criteria: a rise and/or fall of troponin with at least one value above the 99th-percentile upper reference limit and evidence of…
- Management
First, reperfuse immediately: primary percutaneous coronary intervention (PCI) is preferred, targeting a first-medical-contact-to-device time of 90 minutes or less; if PCI cannot be delivered within…
- Complications
Cardiogenic shock and acute heart failure: the leading causes of death (acute heart failure).
- Prognosis
Time-dependent: shorter ischemic time means smaller infarcts and better survival.
- Prevention
Aggressive secondary prevention: lifelong aspirin, a high-intensity statin to an LDL goal below 70 mg/dL (often lower), dual antiplatelet therapy for the recommended duration, and guideline-directed therapy for reduced ejection fraction.
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Related articles
- Non-ST-elevation myocardial infarction (NSTEMI)
Non-ST-elevation myocardial infarction is acute myocardial injury from partial or intermittent coronary occlusion, diagnosed by ischemic symptoms and a rising troponin without diagnostic ST elevation. Management is antiplatelet and anticoagulant therapy with risk stratification (TIMI or GRACE) guiding the timing of an invasive coronary strategy.
- Acute heart failure
Acute heart failure is the rapid onset or worsening of heart failure symptoms requiring urgent therapy, most often pulmonary congestion from a precipitant such as ischemia, arrhythmia, or nonadherence. Management is oxygen, intravenous diuretics, and vasodilators for the congested-but-perfused patient, with inotropes or support for the hypoperfused patient.
- Cardiac tamponade
Cardiac tamponade is life-threatening compression of the heart by a pericardial effusion, impairing diastolic filling and cardiac output. It presents with hypotension, distended neck veins, and pulsus paradoxus, is confirmed by echocardiography, and is treated by urgent pericardiocentesis; avoid vasodilators and aggressive diuresis.
- Acute pericarditis
Acute pericarditis is inflammation of the pericardium, most often viral or idiopathic, presenting with pleuritic chest pain relieved by sitting forward, a pericardial friction rub, and diffuse ST elevation with PR depression. Treatment is an NSAID plus colchicine, and the main hazards are effusion, tamponade, and recurrence.
- Aortic dissection
Aortic dissection is a tear in the aortic intima allowing blood to split the media, creating a false lumen, and is a surgical emergency. Type A (ascending) dissection needs emergency surgery, while type B (descending) is usually managed medically with rapid heart-rate and blood-pressure control; the priority is impulse control with a beta-blocker first.
- Pulmonary embolism
Pulmonary embolism is thrombus, usually from a lower-extremity deep vein thrombosis, obstructing the pulmonary arterial circulation and causing V/Q mismatch, right ventricular strain, and hypoxemia. Diagnosis follows Wells criteria (with PERC in low-risk patients) to sequence D-dimer, CT pulmonary angiography, and V/Q scanning, and management is risk-stratified anticoagulation escalating to thrombolysis or embolectomy for hemodynamic instability.
- Gastroesophageal reflux disease (GERD)
GERD is retrograde reflux of gastric contents into the esophagus causing heartburn and regurgitation, diagnosed clinically and confirmed by response to an empiric PPI trial, with endoscopy reserved for alarm features or refractory symptoms. Management proceeds from lifestyle measures through an 8-week once-daily PPI trial, dose escalation or agent switch for partial response, and fundoplication for medication-refractory or regurgitation-predominant disease.
- Myocarditis
Myocarditis is inflammation of the myocardium, most often postviral or immune-mediated, presenting across a spectrum from a mild chest-pain syndrome mimicking myocardial infarction to fulminant heart failure and arrhythmia. Diagnosis relies on cardiac MRI (or biopsy for severe or refractory cases), and treatment is supportive heart-failure care, with cause-specific immunosuppression for giant cell, checkpoint-inhibitor, and autoimmune myocarditis.