清水 優美¹, 田辺 一明², 浅沼 俊彦¹, 吉冨 裕之¹, 小林 賀奈子¹, 大野 美和¹, 加藤 晴美¹, 佐野 和也¹, 石橋 豊¹, 島田 俊夫¹

Hiromi SHIMIZU¹, Kazuaki TANABE², Toshihiko ASANUMA¹, Hiroyuki YOSHITOMI¹, Kanako KOBAYASHI¹, Miwa ONO¹, Harumi KATO¹, Kazuya SANO¹, Yutaka ISHIBASHI¹, Toshio SHIMADA¹

¹島根医科大学第四内科, ²Mayo Clinic

¹Fourth Department of Internal Medicine Shimane Medical University, ²Division of Cardiovascular Disease and Internal Medicine Mayo Clinic

キーワード : Atrial fibrillation, Electrical cardioversion, Left atrial thrombus, Transesophageal echocardiography

A 72-year-old woman with atrial fibrillation was admitted the hospital for electrical cardioversion. Left atrial appendage (LAA) flow velocity recorded by transesophageal echocardiography (TEE) was 10 cm⁄s before cardioversion, and no thrombus was detected in the LAA. Anticoagulant therapy with warfarin was begun 14 days before cardioversion, and adequate stable prothrombin time was attained. Electrical cardioversion was performed, and sinus rhythm was restored with a shock energy of 100 joules. Follow-up TEE performed 4 days after cardioversion showed a de novo thrombus in the LAA, and LAA flow velocity (6 cm⁄s) was slower than before cardioversion. Anticoagulation therapy was continued, and TEE 18 days after cardioversion demonstrated that the thrombus had disappeared. There was no embolic event. LAA flow velocity increased to 30 cm⁄s. These findings suggest the necessity of adequate anticoagulation and follow-up TEE observation after cardioversion in patients with slow LAA flow velocity during atrial fibrillation.