断層心エコー図法にて診断しえた右上大静脈欠損，左上大静脈遺残を伴なうFallot四徴症の一例

Two-dimensional echocardiographic diagnosis of a case with congenital absence of the right superior vena cava associated with tetralogy of Fallot

　右上大静脈欠損症は，稀な先天性心奇形であり，通常左上大静脈遺残を伴なう。種々の先天性心疾患に合併し，人工心肺を使用する心内修復術，大血管転換症の際のMustard手術，右上大静脈を使用するGlenn手術，経静脈的pacemaker植え込みの際などには，その手技上術前診断が重要である^1,2）。現在までの報告では，心臓カテーテルの際そのカテーテルの走行異常により右上大静脈欠損が疑われ，右腕頭あるいは右鎖骨下静脈の造影により診断されている^1）。今回我々は，コントラスト断層心エコー法を用い，本症を非侵襲的に診断し若干の知見を得たので報告する。

Absence of the RSVC with PLSVC is an uncom-mon cardiac malformation. In general the diagnosis of this condition can be obtained during cardiac catheterization by the course of the catheter and angiography. We reported a case of the congenital absence of the RSVC diagnosed by the two-dimensional echocardiography. This case had the very large coronary sinus and contrast echocardio-graphy from the right cubital vein revealed that contrast material entered the right atrium throughlarge coronary sinus without passing through the RSVC, which indirectly confirmed the absence of the RSVC.

We compared the cross sectional size of the coronary sinus between the cases with the absent RSVC and with the PLSVC on the long axis view of the left ventricle. The result showed the former size was three times larger than the latter one, which gave the diagnostic clue to the absent RSVC on the two-dimensional echocardiography.

It is sometimes difficult to obtain the satisfactory image of the RSVC upon suprasternal view be-cause of lung interference in the cyanotic cogenital heart disease. In this situation, hemodynamic consideration using the contrast echocardiography from the right or left cubital vein can indirectly confirm the diagnosis of the absent RSVC.