ST Segment Depression

Horizontal or downsloping ST with upright T waves-> probable ischemia
  • “Someone stepped on the ST segment”
  • May be diffuse or localized
  • Diffuse ST depression with ST elevation in aVR: possible left main obstruction
  • ST depression during PSVT is not diagnostic
Downsloping ST depression with inverted T waves -> probable LV strain​
  • Usually in association with LVH
  • LVH, strain and chest pain: ECG not very useful
Upsloping ST depression (J point depression) -> nonspecific
  • ST usually back to baseline 2 mm after the end of QRS
  • Causes: anemia, metabolic abnormalities, MVP, normal variant
Scooped ST depression -> digitalis or hypercalcemia
  • Usually seen in left leads (I, V5-V6)
  • QT interval may be shortened
  • May be associated with other markers of digitalis effect
    • Bradycardia, first degree AV block, atrial fibrillation with slow
    • Ventricular response, digitalis-toxic tachyarrhythmias