123I-BMIPP心筋SPECTで心筋虚血を検出しえた左冠動脈左室瘻の1例

Left Coronary Artery-left Ventricular Fistula Showed Abnormal Findings on 123I-BMIPP Myocardial SPECT

　β-methyl-p-（¹²³I）-iedophenylpentadecanoic acid（¹²³I-BMIPP）心筋SPECTが左冠動脈左室瘻の心筋虚血の検出に有用であった稀な1例を報告する．患者は79歳，女性．労作時胸部不快感が出現し，¹²³I-BMIPP心筋SPECTで心筋虚血が疑われ，精査のため入院．入院時心電図は心房細動と左室肥大，胸部X線写真では心拡大がみられた．心エコー図では左房拡大と僧帽弁逆流，三尖弁逆流が認められた．99m-Tc-tetrofosmin心筋SPECTのATP負荷には異常なかったが，¹²³I-BMIPP心筋SPECTの初期像で心室中隔の軽度集積低下，後期像で心室中隔から心尖部の中等度集積低下所見が認められた．心臓カテーテル検査の左室造影には異常はなかったが，冠動脈造影で左冠動脈対角枝から左室に瘻口が認められた．ドプラガイドワイヤーによる検討では左冠動脈対角枝に冠血流予備能の低下がみられた．

　We encountered a rare case of left coronary arteryleft ventricular fistula with abnormal findings on β-methy-p-(¹²³I)-iodophenylpentadecanoic acid (¹²³I-BMIPP) myocardial SPECT. The patient was an 79-year-old-female who had chest discomfort on effort, and was diagnosed with suspected myocardial ischemia on ¹²³I-BMIPP myocardial SPECT. Electrocardiogram on admission showed atrial fibrillation and left ventricular hypertrophy. Chest X-P revealed cardiac enlargement. Echocardiogram revealed enlargement of the left atrium, and mitral and tricupid regurgitation. Although 99m-Tc-tetrofosmin myocardial SPECT with ATP stress test showed normal findings, ¹²³I-BMIPP myocardial SPECT revealed mildly reduced uptake on the ventricular septum on initial images and moderately reduced uptake on the ventricular septum to the apex on delayed images. On cardiac catheterization, the left ventriculogram showed normal findings. Coronary arteriography showed no organic stenosis and diagonal branch of the left coronary artery-left ventricular fistula. Decreased coronary flow reserve of the diagonal branch of the left coronary artery was detected using a Doppler guide wire.