What are the causes and management of persistent ST elevation in an electrocardiogram (ECG) in a patient with a history of cardiovascular disease, hypertension, or hyperlipidemia?

Persistent ST Elevation on ECG: Causes and Management

Primary Cause Requiring Immediate Action

Persistent ST-segment elevation most commonly signifies acute total coronary artery occlusion requiring immediate reperfusion therapy with either fibrinolytic treatment or primary percutaneous coronary intervention (PCI). 1

Acute Life-Threatening Causes

ST-Elevation Myocardial Infarction (STEMI)

• Complete occlusion of a major coronary artery is the primary mechanism, caused by atherosclerotic plaque rupture with subsequent thrombosis formation 1
• Immediate reperfusion therapy is indicated—either thrombolysis (if not contraindicated) or primary angioplasty (if technically feasible) 1
• Administer aspirin 150-300 mg oral loading dose immediately, followed by 75-100 mg daily 2
• Add P2Y12 inhibitor (clopidogrel) in addition to aspirin for 12 months 2
• Initiate low-molecular-weight heparin or unfractionated heparin immediately 2

Left Main or Multi-Vessel Disease

• ST elevation in aVR with diffuse ST depression in ≥6 other leads indicates global myocardial ischemia from severe coronary artery disease involving distal left main and ostial right coronary arteries 3
• Requires very high-risk invasive strategy within 2 hours if accompanied by hemodynamic instability, cardiogenic shock, or refractory chest pain 2

Chronic/Non-Acute Causes of Persistent ST Elevation

Left Ventricular Aneurysm

• Persistent ST elevation lasting >2 weeks after anterior myocardial infarction does not resolve and indicates ventricular aneurysm formation 4
• In anterior infarctions, ST elevation persists in 64% of patients at 1-6 months follow-up, compared to only 5% with inferior infarctions 4
• Associated with advanced anterior and apical asynergy on ventriculography—62% of patients with severe wall motion abnormalities show persistent ST elevation 4
• Echocardiography should be obtained to evaluate regional and global left ventricular function 2

Hypertrophic Cardiomyopathy

• Can present with persistent ST segment elevation of acute injury type that mimics STEMI 5
• Echocardiography reveals left ventricular hypertrophy with outflow tract obstruction and high intracavity pressure gradient 5
• ST elevation remains unchanged on serial ECGs over time 5

Left Bundle Branch Block (LBBB)

• Creates diagnostic difficulty in identifying true STEMI 6, 7
• Apply Sgarbossa criteria: concordant ST elevation ≥1 mm in leads with positive QRS (specificity 92%), ST depression ≥1 mm in V1-V3 (specificity 96%), or excessive discordant ST elevation ≥5 mm (specificity 82%) 6
• Concordant ST elevation has 96% positive predictive value for acute MI in LBBB patients 6

Other Structural/Electrical Causes

• Acute pericarditis: diffuse ST elevation with PR depression 7
• Early repolarization syndrome: benign variant with J-point elevation 7
• Left ventricular hypertrophy pattern: can produce ST elevation in lateral leads 7
• Ventricular paced rhythm: creates LBBB-like pattern with secondary ST changes 7

Critical Diagnostic Algorithm

Step 1: Immediate ECG Assessment

• Obtain 12-lead ECG within 10 minutes and compare with prior tracings to determine if ST changes are new or chronic 2
• Record additional leads V7-V8 or V4R when posterior or right ventricular infarction suspected 1

Step 2: Cardiac Biomarkers

• Measure high-sensitivity cardiac troponin at 0 and 1 hour, with additional testing at 3-6 hours if inconclusive 2
• Do not wait for troponin results to initiate reperfusion treatment if STEMI is suspected 1

Step 3: Risk Stratification

• Very high-risk features (requiring invasive strategy <2 hours): hemodynamic instability/cardiogenic shock, refractory chest pain despite medical therapy, life-threatening arrhythmias, acute heart failure 2
• High-risk features (requiring invasive strategy <24 hours): rising troponin, dynamic ST/T-wave changes, GRACE score >140 2

Step 4: Echocardiography

• Perform to assess left ventricular function, identify wall motion abnormalities, and rule out alternative diagnoses including hypertrophic cardiomyopathy, pericarditis, and ventricular aneurysm 2, 5

Critical Pitfalls to Avoid

• Never delay reperfusion therapy in suspected STEMI while waiting for troponin results—the therapeutic window is critical for mortality reduction 1
• Exclude intracranial hemorrhage before administering antithrombotic therapy if severe hypertension (>180/120 mmHg) and headache are present 2
• Recognize STEMI mimics (pericarditis, early repolarization, hypertrophic cardiomyopathy) to avoid unnecessary invasive procedures 5, 7
• Apply Sgarbossa criteria systematically in LBBB patients rather than dismissing ST elevation as expected secondary changes 6
• Consider non-cardiac causes of ST elevation in aVR with diffuse ST depression, including severe anemia from GI bleeding and drug-induced vasospasm, which contraindicate anticoagulation 3

Disposition

• Admit all patients with new persistent ST elevation to intensive cardiac care unit with continuous telemetry monitoring 2
• Plan coronary angiography within 12-24 hours for high-risk patients with elevated troponin, dynamic ST changes, or GRACE score >140 2