ST segment elevation

Background

• Its presence must be explained (there is no "nonspecific ST elevation")
• Not a specific marker for STEMI

Differential Diagnosis

ST Elevation

• Cardiac
  • ST-segment elevation myocardial infarction (STEMI)
  • Post-MI (ventricular aneurysm pattern)
  • Previous MI with recurrent ischemia in same area
  • Wellens' syndrome
  • Coronary artery vasospasm (eg, Prinzmetal's angina)
  • Coronary artery dissection
  • Pericarditis
  • Myocarditis
  • Aortic dissection in to coronary
  • Left ventricular aneurysm
  • Left ventricular pseudoaneurysm
  • Early repolarization
  • Left bundle branch block
  • Left ventricular hypertrophy (LVH)
  • Myocardial tumor
  • Myocardial trauma
  • RV pacing (appears as Left bundle branch block)
  • Brugada syndrome
  • Takotsubo cardiomyopathy
  • AVR ST elevation
• Other thoracic
  • Pneumomediastinum
  • Pneumothorax
  • Pulmonary embolism
• Metabolic
  • Drugs of abuse (eg, cocaine, crack, meth)
    • Cocaine chest pain
  • Hyperkalemia (only leads V1 and V2)
  • Hypothermia ("Osborn J waves")
• Medications
  • Tricyclic (TCA) toxicity
  • Digoxin

Diagnosis

Early Repolarization versus STEMI

• Early Repolarization suggested by:
  • ST elevation <4mm
  • Notched J point
  • Concave or saddle-back ST morphology
  • No reciprocal changes

LVH versus STEMI

• Difficult to exclude MI in pt with LVH (pt already at risk for MI)
• Best aid is prior ECG or serial ECGs

LBBB versus STEMI

See Sgarbossa's Criteria

STEMI

• ST elevation in those leads that reflect the distribution of a single coronary artery
  • RCA: II, III, aVF (inferior)
  • LAD: V1-V4 (antero-septal)
  • Circumflex: V5-V6, I, aVL (lateral)
  • Dominant left circulation: infero-lateral
• ST morphology
  • Concave up versus convex
    • Convex has Sp 97%, Sn 77%
• Look for reciprocal ST depression
  • 35% of anterior STEMI have ST depression in inferior leads
  • 80% of inferior STEMI have ST depression in anterior leads
    • However, may represent reciprocal changes OR posterior STEMI

See Also

• ECG (Main)
• ACS - ECG

Source

• ST Elevation Lecture, Dr. Niemann, Harbor-UCLA