ペースメーカ心電図で著明なST-T変化を認めた急性心筋梗塞の1例

A Case of Acute Myocardial Infarction with Serial ST-T Change during Permanent Ventricular Pacing

　症例は83歳，女性．1995年3月完全房室ブロックにて，VDDペースメーカ植え込み術を施行された．1996年5月22日，胸痛発作のため緊急入院となった．発作より約3時間後の来院時の心電図ではペースメーカリズムで，II,III,aV_F，V₅，V₆にて著明なST上昇とT波増高，I,aV_LでのST低下を認めた．心臓超音波検査では左室後下壁の壁運動低下を，また血液検査ではCPK高値（最高3,035 U／l,MB310）の所見を認め，急性心筋梗塞と診断した．その後心電図のST-T変化は軽減したが，肺炎を合併し，呼吸不全で死亡した．病理解剖では，右冠状動脈の完全閉塞および左室後下壁の菲薄化の所見を認めた．ペースメーカ心電図での急性心筋梗塞の診断は困難なことが多いが，本症例では来院時に著明なST-T変化を認め，診断可能であった．ペースメーカ挿入例でも急性心筋梗塞発症早期であれば心電図変化から心筋梗塞を示唆できると考えられた．

We report a case of a patient with acute myocardial infarction (AMI) with serial ST-T change during ventricular pacing. The patient was an 83-year-old woman who was implanted with a VDD pacemaker because of complete AV block. She was admitted to our hospital because of prolonged chest pain. Electrocardio-gram showed ST-segment elevation and T-wave abnor-malities in leads II, III, aV_F, V₅, V₆, and ST-depression in leads I , aV_L. Echocardiography revealed hypo-kinetic wall motion in the postero-inferior wall, and serum level of CPK was highly elevated (the peak CPK: 3,035U/l, MB310). Considering the above date, the patient was diagnosed an AMI. The ST-T change recovered, but the patient suffered an attack of pneumo-nia, and died for respiratory failure. Postmortem exami-nation showed complete occlusion of the rigit coronary artery and thinning of the left ventricular posterior wall. Although it is difficult to diagnose AMI with ventricular pacing, this case suggests that electrographic ST-T change during the acute phase of AMI is useful in the diagnosis.