For Patients & General Readers

A STEMI, or ST-elevation myocardial infarction, is a severe type of heart attack where a major artery supplying blood to the heart becomes completely blocked. This blockage starves a portion of the heart muscle of oxygen, causing damage. It's a life-threatening emergency requiring immediate medical attention to restore blood flow and minimize heart damage.

Clinical Overview

STEMI represents a transmural myocardial infarction caused by complete occlusion of a coronary artery, leading to sustained myocardial ischemia and necrosis. Prompt diagnosis and reperfusion therapy are critical to salvage myocardium and improve outcomes.

Clinical Presentation

Sudden onset of severe, crushing, or pressure-like chest pain, often radiating to the left arm, jaw, or back.
Dyspnea, diaphoresis, nausea, vomiting, and syncope.
Patients may present with signs of cardiogenic shock or heart failure.
Electrocardiogram (ECG) demonstrating ST-segment elevation in contiguous leads.
Elevated cardiac biomarkers (e.g., troponin).

Signs & Symptoms

Symptoms (Patient-Reported)

Chest pain or discomfort (pressure, squeezing, fullness, or pain)
Pain radiating to the jaw, neck, back, or arms
Shortness of breath
Nausea or vomiting
Sweating
Dizziness or lightheadedness
Unusual fatigue

Signs (Clinician-Observed)

Diaphoresis (profuse sweating)
Tachycardia or bradycardia
Hypotension or hypertension
Cool, clammy skin
Jugular venous distension (if heart failure present)
New or worsening heart murmurs

Differential Diagnoses

Condition	Distinguishing Feature
Unstable Angina	ECG typically shows ST depression or T-wave inversion, or is normal; cardiac biomarkers are usually negative.
Pericarditis	Chest pain is often pleuritic, positional (worse when lying flat, better when sitting up), and may be relieved by leaning forward. ECG shows diffuse ST elevation, not confined to contiguous leads.
Aortic Dissection	Sudden onset of severe, tearing chest pain, often radiating to the back. May have pulse deficits or neurological symptoms. CXR may show widened mediastinum.
Pulmonary Embolism	Sudden onset of pleuritic chest pain, dyspnea, tachypnea, and hypoxemia. ECG may show S1Q3T3 pattern or right heart strain.
Gastroesophageal Reflux Disease (GERD)	Chest pain is often burning, related to meals, and relieved by antacids. Absence of ECG changes and elevated cardiac biomarkers.
Musculoskeletal Pain	Pain is typically reproducible with palpation or movement, and not associated with systemic symptoms or ECG changes.

Red Flags — Seek Immediate Care

New onset or worsening chest pain suggestive of myocardial ischemia.
ECG findings of ST-segment elevation in contiguous leads.
Hemodynamic instability (hypotension, shock).
Presence of new or worsening heart failure symptoms.

Key Investigations

12-lead Electrocardiogram (ECG) - crucial for identifying ST-segment elevation.
Cardiac Biomarkers (Troponin I or T) - serial measurements to detect myocardial injury.
Complete Blood Count (CBC), Basic Metabolic Panel (BMP), Coagulation studies.
Echocardiogram - to assess ventricular function, wall motion abnormalities, and complications.
Coronary Angiography - gold standard for definitive diagnosis and guiding revascularization.

Management Overview

Immediate reperfusion therapy is paramount, including primary percutaneous coronary intervention (PCI) as the preferred strategy if available within guideline-recommended timeframes. If PCI is not feasible, fibrinolytic therapy should be administered promptly. Adjunctive medical therapy includes aspirin, P2Y12 inhibitors, anticoagulation, beta-blockers, and statins.

Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. TruelyserMD does not replace clinical judgement.