足立 久信, 信岡 祐彦, 長嶋 淳三, 粟屋 透, 徳岡 伸一, 今井 行子, 田中 裕之, 柴本 昌昭, 籏野 誠二, 三宅 良彦, 村山 正博

Hisanobu ADACHI, Sachihiko NOBUOKA, Junzo NAGASHIMA, Toru AWAYA, Shinichi TOKUOKA, Yukiko IMAI, Hiroyuki TANAKA, Masaaki SHIBAMOTO, Seiji HATANO, Fumihiko MIYAKE, Masahiro MURAYAMA

聖マリアンナ医科大学内科学教室 (循環器内科)

Division of Cardiology, Department of Internal Medicine, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki-shi 216-8511, Japan

キーワード : Atrial septum, Foramen ovale, Hypertrophic cardiomyopathy, Left-to-right shunt

A 63-year-old Japanese man was admitted to this institution after experiencing shortness of breath on effort for 1 month. Eleven years earlier, at age 52, he had visited our hospital because of paroxysmal atrial fibrillation. An echocardiogram obtained at that time demonstrated myocardial hypertrophy with asymmetric septal hypertrophy (ASH), consistent with a diagnosis of hypertrophic cardiomyopathy (HCM). The atrial fibrillation became chronic at age 55, and he had a cerebral embolism at age 60. Transthoracic echocardiographic examination conducted on admission showed marked dilatation of the left atrium, while color Doppler imaging showed the presence of shunt flow from the left to the right atrium. Transesophageal echocardiography demonstrated a slitlike atrial septum, and left-to-right shunt flow through the slit was detected. We concluded that left ventricular diastolic dysfunction associated with HCM and atrial fibrillation led to marked left atrial dilatation and stretched the foramen ovale, thereby accounting for the presence of shunt flow from the left to the right atrium.