左上大静脈遺残症を合併した特発性右房拡張症

Idiopatbic enlargement of the right atrium with persistent superior vena cava

　症例は69歳の男性で，健診で胸部x線上心拡大を指摘されていたが，68歳時に労作時呼吸困難および下肢の浮腫が出現するまで自覚症状はなかった。症状が増悪したため来院。理学所見では，頸静脈怒張，III音およびIII度の汎収縮期雑音，また肝腫および浮腫を認めた。心電図は心房細動を示し，心エコー，MRIで右室拡大と著明な右房拡大，また左上大静脈遺残を認めた。心臓カテーテル検査その他で右房拡大の原因となる器質的心疾患は認められなかった。特発性右房拡張性はまれな疾患であり，一般に症状は少ないものが多い。我々は左上大静脈遺残症を合併した本症の1例を経験したので若干の文献的考察を加えて報告する。

A 69 year-old male, who had been found (duringa routine roentgenogram of the chest at an annual check-up) to have cardiomegaly, had been asympto-matic until 63 years of age, when DOE and swel-ling of the legs appeared. He visited our hospital because these symptoms had become more servere. Physical examination revealed JVD, third heart sound and a grade 3 holosystolic murmur, hepato-megaly and edema in the lower legs. His ECG showed atrial fibration. His chest X-P showed marked cardiomegaly and rt pleural effusion.

His echocardiography and MRI revealed a marked enlargement of the right atrium and a slight enlar-gement of the right ventricle. The latter also showed persistent left superior vena cava. The cardiac catheterization, angiocardiography and intracavitary electrocardiography revealed no organic cardiac disease which induced enlargement of the right atrium. The idiopathic enlargement of the right atrium is a rare disease. Patients suffering from this disease are asymptomatic in most cases.

We reported the idiopathic enlagement of the right atrium with persistent left superior vena cava in this paper.