ST elevation

Description




非 STEMI 的情況

Normal ST Elevation at the Transition Zone. Elevation of the ST segment is common in normal individuals at the transition zone which is usually in V₂, V₃, or V₄ (arrows). This is a normal finding often described as “high take-off” of the ST segment. Very often, the T waves are also peaked and taller than the R wave at the transition zone. This is also a normal finding.

• ST↑ over transitional zone：V2~V4 正常人常見。ST為up-sloping 不是iso-electric



Early Repolarization. ST segment elevation is noted in V₃ to V₆ (arrows), which can be mistaken for acute myocardial injury. There is no reciprocal ST depression in any lead and a prominent notch is present at the end of the R wave in V₄. Note that the height of the ST segment in V₆ measures 1.0 mm and the height of the T wave measures 6 mm (ST elevation/T wave ratio <25%). A ratio ≤25% suggests early repolarization. If pericarditis is being considered, the ratio is >25% because the height of the T waves is generally lower in pericarditis.

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  Early Repolarization during Holter Monitoring. Three rhythm strips with different heart rates are shown above in the same patient undergoing Holter monitoring. Note that there is more pronounced ST segment elevation because of early repolarization when the heart rate is slower than when the heart rate is faster. Arrows point to the ST segment elevation. HR, heart rate.

• Benign Early Repolarization：胸前 leads：J point↑，ST↑容易和 transmural MI 搞混。

• ST↑：concave，向上。會出現在 V2-V6, II, III, aVF
• 不伴隨 reciprocal ST↓
• J點在ST↑的leads常有 notch
• HR↓ ST↑較prominent accentuated, HR↑會變得 isoelectric less pronounced
• ST-T ratio 在V6常 ≦25%。DDx. pericarditis（ST-T≧25%因為ST↑較高 ）
• 無法確定還是要當成 MI 處理

• hyperkalemia：與STEMI容易搞混。出現時表K+>8mEq/L
• LBBB：ST, T與QRS為 discordant。在有 deep S(V1~V3) 會有ST↑, upright T；在有 tall R (V5, V6) 會有 ST↓, invert T。
• LVH：ST, T和QRS為discordant。在有 deep S(V1~V3) 會有ST↑, upright T
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