左室に開口した右冠動脈瘻の1例—超音波および核医学検査法によるアプローチ

A case of right coronary arterial fistula opening into the left ventricle:Assessment by using echocardiography and radionuclide cardioangiography

　冠動脈瘻は心臓カテーテル法による選択的冠動脈造影が普及するにつれて，その診断は容易になり，現在までに200例以上の報告がなされ，決して稀な疾患ではなくなってきた。しかし，その大部分は右心系に開口する冠動脈瘻であり，左室開口例は少ない。われわれは最近，心雑音が聴取されず負荷心電図上ST降下が認められたため，初診時に虚血性心疾患と診断されたが，冠動脈造影により左室に灌流する右冠動脈瘻と判明した57歳男性の1例を経験した。心エコー図，核医学などの非観血的手法による同症例へのアプローチによって，興味ある知見を得たので報告する。

A case of right coronary arterial fistula opening into the left ventricle was studied non-invasively by the echo cardiographic and radionuclide methods. A patient was a 57-year-old man who had been admitted into I wate -Medical University Hospital with an atypical chest discomfort. The findings ofST depression in precordial leads V_4-5 were noted on exercise ECG, which led to a diagnosis of ische-mic heart disease. However, it was disclosed by means of the coronary arteiograms that a fistula of the right coronary artery communicated with the left ventricle. The following results were obtained by echcardiograms : 1) a markably dilated right coronary artery was seen on short axis tomograms of the aorta, 2) an enlarged right coronary artery was demonstrated on the left side of the liner by the subxiphoid approach, 3) fluttering of the posterior cusp of the mitral valve and its tendinous cords was found throughout the diastole, 4) diameters of the aorta, left atrium and ventricle increased, and 5) movement of the interventricular septum and the posterior wall of the left ventricle decreased. On the other hand, the next results were obtained by theradionuclide study : coronary perfusion decreased evidently in the inferior wall both directly after and 4 hours after the stress TI-201 myocardial perfusion scan, but there was no redistribution of TI-201 radio activity in the same region. Radionuclide study of the LAO area showed an abnormal blood pooling in the proximity of the sinus of Valsalva. Analyti-cal findings of timeradioactivity enrues in three regions of interest (i.e. right ventricle, left ventricle and area showing the abnormal blood pooling) revealed that the peaked radioactivity of these cur-des coincided with the sites of abnormal blood pool-ing. Therefore, echocardiographic and radionuclide studies are useful and have a pathognomonic role for diagnosis of the coronary arterial fistula at the out patients clinic.