ST segment depression

Evaluation

• Contour: Most→Least concerning for ischemia: Planar/Flat (90%) → Concave up (33%) → Downsloping with Asymmetric inverted T-wave (not ischemic/strain pattern)
• Assume posterior STEMI or reciprocal changes to STEMI until proven otherwise
• Indicators of ischemia:
  • >0.5mm depression from baseline (especially >1mm) in two or more contiguous leads
  • Transient depression
  • Morphology that is flat or downsloping
• Strain: 
  
  • tall R wave
  • only in lateral leads (not anterior)
  • "checkbox" or asymmetric TWI
  • down sloping pattern

Differential Diagnosis

• Posterior MI (including posterior STEMI)
• RV strain
• NSTEMI
• Reciprocal changes
• Electrolyte Disorders (e.g. hypokalemia)
• LVH with strain pattern (repolarization abnormality)
• Digoxin effect (not indicative of toxicity)

See Also

• ECG (Main)

References

ST Elevation Lecture, Dr. Niemann, Harbor-UCLA

Authors

Ross Donaldson