宮本 亜矢子¹, 湯田 聡², 高木 覚³, 小林 みち子¹, 中原 学史³, 板垣 恭嗣⁴

Ayako MIYAMOTO¹, Satoshi YUDA², Satoru TAKAGI³, Michiko KOBAYASHI¹, Norifumi NAKAHARA³, Yasushi ITAGAKI⁴

¹札幌社会保険総合病院検査部, ²札幌医科大学医学部臨床検査医学, ³札幌社会保険総合病院内科循環器科, ⁴GEヘルスケアジャパン株式会社

¹Department of Clinical Laboratory, Sapporo Social Insurance General Hospital, ²Department of Clinical Laboratory Medicine, Sapporo Medical University School of Medicine, ³Department of Cardiology, Sapporo Social Insurance General Hospital, ⁴GE Health Care Japan Corporation

キーワード : cardiac tumor, cardiac fibroma, 2D speckle tracking, myocardial dysfunction, echocardiography

症例は74歳，男性．当院糖尿病内科に通院中，発作性心房細動を認めたため，2008年12月心エコー検査を施行したところ，左室後壁に2×5 cmの腫瘤を指摘された．手術歴や外傷歴はなく，3ヵ月後の心エコー検査でも腫瘤径は変化せず，全身のCT検査で悪性腫瘍を示唆する所見を認めないことから，良性心臓腫瘍と判断し，経過観察を行っていた．冠動脈CT検査で前下行枝に狭窄病変の存在が疑われたため，2009年12月に腫瘍精査も兼ねて入院となった．臨床所見及び，その形態やエコー輝度，CT所見から鑑別した結果，線維腫である可能性が最も考えられた．入院時の心エコー検査で，2次元（2D）スペックルトラッキング法を用いて長軸，短軸及び円周方向のstrain解析を行ったところ，腫瘍部位に一致する後壁基部に限局した局所心機能異常が認められた．冠動脈造影では，後壁を灌流する右冠動脈及び左回旋枝に狭窄病変を認めなかったことから，腫瘍の存在そのものが，局所心機能異常の原因の一つとなる可能性が考えられた．2Dスペックルトラッキング法は，左室腫瘍周囲の潜在的心機能異常の検出に有用である可能性が示唆された．

A 74-year-old man presenting with paroxysmal atrial fibrillation was referred to our hospital in December 2008. Two-dimensional echocardiography showed a 2 x 5 cm mass in the posterior wall of the left ventricle. There was no evidence of malignancy and there was no significant change in mass size during the 3-month follow-up period. The mass was thus judged to be a benign cardiac tumor, and the patient was followed at our hospital. He was admitted to our hospital in December 2009, however, when computed tomography angiography of the coronary artery revealed stenosis in the left anterior descending artery. The characteristics of the mass were assessed by computed tomography and two-dimensional echocardiography, and the clinical diagnosis of the mass was thought likely to be cardiac fibroma. Regional left ventricular function was assessed by two-dimensional speckle tracking imaging. Reduced longitudinal and radial strains were found in the basal posterior wall of the left ventricle. Further, the circumferential strain pattern in the posterior wall was precisely opposite to that in the septal wall. The coronary angiogram showed normal right and left circumferential coronary arteries, suggesting that the tumor itself was affecting regional myocardial function around the tumor. Hence two-dimensional speckle tracking imaging may be useful for detecting subclinical regional myocardial dysfunction around a left ventricular tumor.