高杉 信寛, 杉山 靖和, 野田 俊之, 加藤 俊彦

Nobuhiro TAKASUGI, Yasukazu SUGIYAMA, Toshiyuki NODA, Toshihiko KATO

岐阜赤十字病院第二内科

Second Department of Internal Medicine, Gifu Red Cross Hospital

キーワード : echocardiography, left atrial ball thrombus, nonvalvular atrial fibrillation

症例は78歳の男性. 前立腺肥大症の術前検査にて労作時の息切れ, 高血圧, 下腿浮腫, 心房細動, 胸部エツクス線像上 心拡大を指摘され, 当科を受診した. 経胸壁心エコー図では肺高血圧, 左房拡大を伴う軽度左室駆出率低下を認めたが, 僧帽弁に器質的異常は認めなかった. うっ血性心不全の診断で, 利尿剤, アンギオテンシンⅡ受容体拮抗剤, ジギタリスにて治療開始した. 1週間後, 自覚症状の改善とともに胸部エツクス線像上も心拡大は改善したが, 治療開始約9日後の経胸壁心エコー図上, 左房内に可動性に富む径16×17 mmの腫瘤性病変を認めた. 経食道心エコー図では, 左心耳入口部近くの左房後壁に細い茎で付着し, 心拍にあわせて振り子様の動きを示していた. 血栓と診断し, 緊急手術を考慮したが, 本人の希望で保存的治療が選択され, ワルファリン投与開始しPT-INR 1.5-2.5の範囲でコントロールされた. ワルファリン開始1週間後の経食道心エコー図では, 血栓は12×14 mmに縮小し, 4週間後の経食道心エコー図上, 血栓は茎の一部を残し完全に消失した. 経過中心房細動は持続していたが, 塞栓症状は認めなかった. 左房内球状血栓症は非弁膜症例では稀であるとされている. 本症例の様に短期間で血栓が出現し, ワルファリン治療で塞栓症状をきたすことなく消失した報告はなく, 極めて稀な症例であると考えられた.

A 78 year-old male was admitted to this institution for prostatectomy. He recently complained of dyspnea on effort and edema in both legs. Preoperative examination showed high blood pressure; cardiomegaly in the chest radiogram; and atrial fibrillation in his electrocardiogram. Transthoracic echocardiography showed pulmonary hypertension, slightly decreased left ventricular ejection fraction, and left atrial dilatation, but no significant mitral valve disorder. Congestive heart failure was diagnosed, and treatment with diuretics, angiotensin II receptor blocker, and digitalis was begun. Both the symptoms and cardiomegaly were improved 1 week after treatment. Transthoracic echocardiography 9 days after admission showed a 16×17 mm mobile ball-like mass in the left atrium. Transesophageal echocardiography showed a spherical mass with a stalk, which was attached to the left atrial posterior wall, near the orifice of left atrial appendage, and showed pendular motion with the heartbeat. We diagnosed the mass as a thrombus and recommended urgent surgery. The patient refused surgery, therefore, his lesion was treated with anticoagulant. He received continuous warfarin and maintained a prothrombin time (PT) international normalized ratio (INR) of 1.5 to 2.0. Transesophageal echocardiography 6 days after warfarin therapy showed that the thrombus measured only 12×14 mm. The thrombus had disappeared 4 weeks after warfarin therapy, the stalk remained and atrial fibrillation continued. The patient experienced no embolic episode or other symptoms during the follow-up period. Left atrial ball thrombus is a rare disorder associated with nonvalvular atrial fibrillation. We could verify the formation of a thrombus during short time and warfarin therapy resolved the thrombus without embolic episode.