心筋梗塞後偽性仮性心室瘤の1例

Pseudo-false Aneurysm of the Left Ventricle after Acute Myocardial Infarction；Report of a Case

はじめに　心筋梗塞後の左室偽性仮性心室瘤は，1981年にStewartらによって最初に報告されたまれな疾患である1）．発症機序は心筋梗塞後の仮性心室瘤と同様に梗塞部位の心筋断裂によるが，仮性心室瘤は心筋断裂が全層に及び，血腫が心外膜にまで到達して心外膜と心囊膜の癒着で瘤が形成されるのに対して，偽性仮性心室瘤は心筋断裂が全層に達することなく心筋壁内に血腫を形成し，同部に左室圧が加わることで瘤が形成される1，2）．瘤壁の病理所見では，真性瘤は心筋組織を含み心内膜の連続性が保たれているのに対し，仮性瘤は心膜，心外膜組織のみで心筋組織を欠くものと定義され，偽性仮性瘤は心筋組織が一部残存するものと定義されている1）．われわれは無症状で経過した偽性仮性心室瘤を経験したので報告する．

A 77-year-old man was admitted to a regional hospital to undergo investigation of abnormal electrocardiographic findings. Coronary angiography revealed 99％ stenosis of the right coronary artery （RCA）segment 3 and 75％ stenosis of the left anterior descending artery （LAD）segment 7. Left ventriculography revealed an aneurysm at the inferior wall of the left ventricle. On computed tomography and echocardiography, a saccular aneurysm at the inferior wall, 15 mm in diameter, was observed. Under the suspicion of a ventricular false aneurysm resulting from myocardial infarction, aneurysmectomy, patch closure of the aneurysmal orifice and coronary artery bypass grafting to the LAD and RCA were performed. No pericardial adhesion to the ventricular aneurysm was observed. His postoperative course was uneventful, and he was discharged from the hospital on the 28th postoperative day in good condition. The pathological examination revealed residual cardiomyocytes with the aneurysmal wall.