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