急性期冠状動脈造影にて異常所見を認めなかった貫壁性前壁梗塞の1例

A case of transmural anterior myocardial infarction without angiographically abnormal finding at acute stage

　近年，急性心筋梗塞（以下AMI）に対して，急性期に冠状動脈造影（以下CAG）が施行されるようになり，AMIの急性期における病態生理が明らかになりつつある。それによると，AMIの急性期には全例責任冠状動脈には高度の冠狭窄が存在するといわれている^1,2）。一方，心筋梗塞（以下MI）の慢性期においてまったく冠狭窄を認めない症例が時に存在し，この原因として，狭窄の見落としないし分離不良，血栓の溶解，冠塞栓，small vessel disease, coronary spasmなどが考えられていた^3）が，近年は特に血栓溶解およびcoronary spasmがその原因として重要視されるようになった^3〜7）。

　今回，著者らは発症18時間後のCAGにて異常所見を認めなかった貫壁性前壁梗塞の1例を経験し，その原因としてcoronary spasmが強く疑われ，早期治療の重要性が認識されたので報告する。

The patient was a 39-year-old man, who had no risk factors except smoking. After ingesting alcohol, he suffered a severe chest pain and was admittedto our hospital 13 hours after the onset. The ECG findings and biochemical data indicated typical ante-rior transmural myocardial infarction, but coronary angiography performed 18 hours after the onset did not revealed any abnormalities. There were several attacks of chest pain accompanying the ST elevation on ECG after admission, and intravenous injection of Isosorbide dinitrate relieved attacks effectively. Although the coronary angiogram obtained at the chronic stage showed no abnormalities, but intraven-ous injection of 0.1 mg Ergonovine maleate induceddiffuse spasm in the left anterior descending coro-nary artery. The left ventriculogram demonstrated extensive akinetic areas over the antero-lateral, apical and septal walls. Such a condition in which the normal coronary artery is observed in the coro-nary angiogram at the acute stage is very rare, and this is the sixth case to have been recorded in the literatures in the world. The major cause of this case was thought to be coronary spasm, so that the importance of early treatment for variant angina or impending infarction was recognized.