相賀 護, 大島 一太, 山田 聡, 田中 信大

Mamoru AIGA, Kazutaka OOSHIMA, Satoshi YAMADA, Nobuhiro TANAKA

東京医科大学八王子医療センター循環器内科

Department of Cardiovascular Medicine, Tokyo Medical University Hachioji Medical Center

キーワード : coronary sinus ostial stenosis, unroofed coronary sinus, transesophageal echocardiography

症例は82歳男性，発作性心房細動の診断にてカテーテルアブレーション治療検討のため，当院紹介となった．経胸壁心エコー図検査で冠静脈洞（CS）の拡大を認め，心尖部二腔像では，CSと左房間で交通しunroofed coronary sinus（UCS）が示唆されたが，右心系の拡大は認めなかった．精査目的で経食道心エコー図検査（transesophageal echocardiography: TEE）を施行した．左上肢からの攪拌生理食塩水による経静脈コントラストエコーでは，左上大静脈遺残は否定的であった．3次元経食道心エコー図検査（3D-TEE）にてCSはCS終末部で左房と交通し，径15 mm大の欠損孔が確認された．さらに冠静脈洞開口部は狭窄し，3D-TEEによる狭窄部の形態は，膜様多孔性であった．UCSに冠静脈洞開口部狭窄を合併しているものと診断した．UCSによるCSを介した左房から右房への短絡血流が冠静脈洞開口部狭窄により制限され，顕著な右心系の容量負荷に至らなかったものと推測された．3D-TEEはUCSおよび冠静脈洞開口部狭窄の形態評価に有用であった．

An 82-year-old male with paroxysmal atrial fibrillation was referred to our hospital for catheter ablation therapy. Transthoracic echocardiography (TTE) showed a dilated coronary sinus (CS), and there appeared to be a communication between the CS and the left atrium (LA) in the two-chamber view, suggestive of unroofed coronary sinus (UCS), but right-sided chambers were not dilated. Transesophageal echocardiography (TEE) was performed for a detailed investigation. Intravenous agitated saline contrast echocardiography through the left upper arm could not identify a persistent left superior vena cava. Three-dimensional transesophageal echocardiography (3D-TEE) revealed a direct communication between the terminal portion of the CS and LA through the deficit hole with a diameter of 15 mm. Moreover, the CS ostium was covered with a fenestrated membranous structure and stenosed. We diagnosed UCS with CS ostial stenosis. The CS ostial stenosis likely restricted the left-to-right shunt flow, preventing remarkable right heart volume overload. 3D-TEE was useful for evaluation of the structure of UCS and CS ostial stenosis.