相賀 護, 大島 一太, 田中 信大

Mamoru AIGA, Kazutaka OOSHIMA, 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 : left atrial appendage ostial stenosis, atrial fibrillation, transesophageal echocardiography, congenital anomaly

心房細動に対するカテーテルアブレーション（radiofrequency catheter ablation: RFCA）の術前検査を施行したところ，左心耳入口部狭窄例を経験したので報告する．症例は65歳，男性．2年前より発作性心房細動に対し内服加療中であった．投薬による心房細動の抑止困難のため，RFCA目的にて受診した．心房内血栓評価目的の経食道心エコー図検査（transesophageal echocardiography: TEE）では左心耳の入口部径は3 mmと狭窄し，カラードプラ法では加速所見を認め，最大通過血流速度は1.2 m/secと亢進していた．心房内に軽度のもやもやエコーを認めたが，心房，左心耳内に血栓像は認めなかった．入院後，RFCAによる肺静脈隔離術を施行し，術後心房細動の再発なく経過した．外科的な不完全結紮を除き，特発性左心耳入口部狭窄の報告例は少数である．その病因および臨床的意義は不明である．今後さらなる症例経験を通じ本病態の臨床経過を評価する必要がある．

We report a case of idiopathic left atrial appendage (LAA) ostial stenosis found incidentally by transesophageal echocardiography (TEE) prior to radiofrequency catheter ablation for atrial fibrillation. A 65-year-old male had a history of paroxysmal atrial fibrillation (PAF), which had been treated for two years. He was referred to our department for the treatment of drug-refractory atrial fibrillation. TEE performed to search for an atrial thrombus showed a narrowed LAA orifice with a diameter of 3 mm. Color Doppler showed a turbulent flow across the LAA orifice. The peak velocity of the LAA orifice determined by continuous wave Doppler evaluation was 1.2 m/sec. Mild spontaneous echo contrast was observed in the left atrium, but no thrombus was found in the LAA and left atrium. After admission, pulmonary vein isolation with radiofrequency catheter ablation was performed. He had no relapse of atrial fibrillation after ablation therapy. With the exception of incomplete surgical ligation of the LAA, idiopathic LAA ostial stenosis is a rare entity. The etiology and clinical implications of this entity remain unclear. Further investigation will be required to confirm the clinical consequences of LAA ostial stenosis.