巨大右房およびPartial atrial standstillを伴う心臓連合弁膜症の1例

A case of valvular disease with giant right atrium and partial atrial standstill

　右房拡張は，心房中隔欠損やエプスタイン奇形などの先天性心疾患や三尖弁疾患などでしばしば認めるが^1），その程度は軽く，巨大右房化することは少ない。

　一方，心房停止（atrial standstill）は心房筋がが機械的および電気的にも活動を示さない状態であり，比較的まれな病態である^2〜4）。

A 60 year old woman of valvular disease with giant right atrium and partial atrial standstill was described. She was admitted to our hospital because of general fatigue and weightloss (5 kg/2 month). The electrocardiogram at admission showed A-V junctional rhythm and absense of P wave in all leads. A chest X-ray film showed remarkable cardiomegaly (CTR 95%). Echocardiogram and pulsed Doppler showed combined valvular disease (aortic stenosis and regurgitation, mitral stenosis and regurgitation, tricuspid stenosis and regurgitation) with enlarged left atrium and giant right atrium.

Atrial electrical activity was recorded at only near the tricuspid valve, and not recorded at the oth-er sites of atrium. Atrial pacing was attempted at multiple sites with stimulus strength of 10 mA, how-ever, there was no atrial activities by atrial pacing in various sites.

The histological findings of the excised giant right atrium showed connective tissue and fatty tissue instead of intact myocardium.

The atrial overload by tricuspid stenosis and regur-gitation for thirty years resulted in the giant right atrium and partial atrial standstill.