起立性低血圧症の精査中に発見された左房粘液腫の1例

A case of cardiac tumor fournd under examination for the cause of orthostatic hypotension

　起立性低血圧症の精査中に発見された左房粘液腫の1例を報告する。患者は61歳男性。2年前より起立または坐位時にのみめまいを感じるようになった。血圧は，臥位で90／50，坐位で64／40であった。心エコー検査にて，左房内腫瘍が見いだされ，それは，患者が臥位におけるよりも坐位をとることによって，左室への落ち込みがより強くなり，左室の拡張期充満を妨げた。腫瘍の摘出術を行ったところ，径3.5cmの粘液腫であり，左房後壁下方に茎を有していた。手術後，主訴および起立性低血圧の所見は消失した。すなわち，血圧は，臥位102／60，坐位98／64となった。体位変換時のめまいは心内腫瘍の症候として重要であるが，本例のように明らかな起立性低血圧のみを呈した例は少なく，起立性低血圧症の鑑別診断として心腫瘍を念頭におく必要を感じた。また，坐位における悪化の状態が心エコー検査にて経時的に観察された例は本例が初めてであると思われた。

We report a case of left atrial myxoma found when examination was made for the cause of ortho-static hypotension. The case was that of a man of 61 years of age. For the previous 2 years, the man had felt dizzy only at the standing or sitting posi-tion. The blood pressure was 90/50 at recumbency and 64/40 at the sitting position. Echocardiograph-ic study revealed a left atrial tumor, which fell into the left ventricular cavity and prevented the blood from filling the left ventricular cavity. This effect was more severe at the sitting position than at re-cumbency. Resection of the tumor was carried out. It was a myxoma with a diameter of 3.5cm with a stalk adhering to the postero-inferior wall of the left atrium. After the removal of the tumor, the patient's complaint and orthostatic hypotension dis-appeared; blood pressure was 102/60 at recumbency and 98/164 at sitting position. Orthostatic dizziness has been reported in some cases as one of the sym-ptoms of the intracardiac tumor. But the state of aggravation at the sitting positon has never been observed during actual echocardiographic study. The myxoma adhered to the postero-inferior wall of the left atrium, which site might be associated with the sympton (orthostatic hypotension).