運動負荷による胸部誘導陰性T波陽転に伴うU波陰性化の意義—左前下行枝病変判定における有用性

Exercise Induced Precordial T Wave Normalization Associated with U Wave Inversion in Detection of Left Anterior Descending Artery Stenosis

　【目的】冠動脈疾患診断における「胸部誘導陰性T波の運動負荷による陽性化」の意義を検討．【方法】対象は，心電図胸部誘導の陰性T波がMasterまたはエルゴメーター法による運動負荷直後に陽性化した冠動脈疾患（CAD）20例と非CAD 14例．負荷心電図上のST,T波高，QTc,U波高の変動を両群で対比検討．【結果】1）CAD群全例に左前下行枝（LAD）狭窄を認めた．2）非CAD群中ST下降は1例にもみられず，CAD群においても，16例（80％）はST不変であった．3）T波高，QTcの変動は両群間で差なし．4）T波陽転時にU波高は非CAD群中7例（50％）で増高したのに対し，CAD群中16例（80％）で陰性化した．5）「T波陽転に伴うU波陰性化」によるLAD狭窄の検出感度は80％，特異度は93％．6）CAD群中15例（75％）は血行再建術を要し，術後には本所見は消失した．【結語】「胸部誘導のT波陽転に伴うU波陰性化」は，LAD狭窄の検出に有用な心電図指標と考えられた．

Although normalization of inverted T wave is not an uncommon finding during exercise tests, it's clinical significance is still unclear.

Exercise 12-lead electrocardiograms (ECGs) were recorded by using Master's 2-step or ergometer. T wave normalization in the anterior chest leads was found in 20 patients with, and 14 patients without coronary artery disease (CAD). Coronary angiography and/or exercise T1-201 myocardial imaging were also performed in every patient. Exercise-induece T wave normalization was defined as “inverted T wave at rest becoming upright during exercise”.