外科手術に関連して発症したカテコラミン心筋症と思われる2例

Two Cases of Suspected Catecholamine-induced Cardiomyopathy Associated with Surgical Operations

　外科手術に関連して心電図上，突然，ST-T変化を生じた2症例を報告した．術前の全身麻酔後一過性に心電図上ST上昇・QT延長を認めた56歳の女性と，術後2日目に心電図上ST上昇・低電位差を認めた78歳の女性例である．ともに急性期にたこつぼ様の心尖部の壁運動低下を認めたが，冠動脈造影上有意狭窄を認めず，エルゴノビン負荷試験も陰性であった．また¹²³I-MIBG心筋シンチグラムでは心尖部・後下壁に集積低下を認めた．本2症例は病歴より手術に伴うストレスによりカテコラミン分泌過多を生じ心筋障害が発生したと考えられた．褐色細胞腫がカテコラミン分泌を促進し心筋障害を生じるとの報告はあるが，今回経験した2例は腹部画像上褐色細胞腫を認めなかった．本例では軽度のカテコラミンの上昇しかとらえられなかったが，心電図上突然の非特異的ST-T変化を認めた場合，虚血性心疾患の鑑別診断として内因性カテコラミンによる心筋障害の可能性も考慮すべきである．

A 56-year-old woman developed temporal ST seg-ment elevation and Q-T prolongation after general anesthesia prior to a surgical operation, and a 78-year-old woman showed ST segment elevation and low amplitude QRS complex on the second postoperative day. Although two dimensional echocardiography and left ventriculography in these 2 patients showed hypo-kinesis of the left ventricular apex in the acute stage, the wall motions repaired themselves in the chronic stage. Coronary angiography did not show significant stenosis and the ergonovine load tests were negative. In I-123- metaiodobenzylguanidine (¹²³I MIBG) myocardial scintigram defect was seen in the apex and in the postinferior segment of the left ventricle. We suspect hypersecretion of catecholamine due to the stress as-sociated with surgical operation affected the myocar-dium.

Several reports have indicated that pheo-chromocytoma promoted the secretion of catecholamine and impaired the myocardium, however, the pheo-chromocytomas could not be recognized in our patients. Neither could be detected any significant elevation of catecholamine levels.

When abrupt non-specific ST-T change is recognized, we should also consider myocardium damage brought about by endogenous catecholamine as a possible factor involved in ischemic heart diseases.