孤立性特発性三尖弁逸脱症の1例

A Case of Isolated Idiopathic Tricuspid Valve Prolapse

要旨　患者は70歳，女性．1998年2月全身の浮腫および呼吸困難を主訴に近医を受診，心不全の診断で入院となり利尿剤を中心とした薬物療法で軽快した．心不全の原因の精査のため当科に入院となった．聴診で胸骨左縁下部に全収縮期雑音を聴取した．心電図は洞調律，正常軸，胸部X線写真上心胸郭比は61％であった．心エコー図で重度の三尖弁逆流と三尖弁前尖の著明な逸脱を認めたが，僧帽弁，大動脈弁，肺動脈弁には異常を認めなかった．心臓カテーテル検査では心房中隔欠損症やEbstein奇形などの合併は否定され，III度の三尖弁閉鎖不全症が認められた．三尖弁置換術を行い，術中所見では三尖弁前尖に付着する腱索の断裂が認められた．胸部外傷歴や胸郭異常もなく，有意な基礎疾患をもたない孤立性特発性三尖弁逸脱症は極めて稀であるため報告する．

　A 70-year-old woman was admitted to the hospitalbecause of anasarca and dyspnea. Upon diagnosis ofcongestive heart failure (CHF) she was treated primarily with diuretics and her general condition improved.She was then transferred to our hospital so as to clarifythe basal disorder of the CHF. During physical examination, a holosystolic murmur was audible in the lower leftborder area of the sternum. Electrocardiogram revealedsinus rhythm and normal axis. The chest X-ray cardiothoracic ratio was 61%. While echocardiogram indicated severe tricuspid regurgitation and severe prolapse of the anterior leaflet of the tricuspid valve, therewere no abnormalities at the mitral, aortic, or pulmonary valves. Cardiac catheterization ruled out an atrialseptal defect as well as an Ebstein anomaly, but rightventriculography reveal third degree tricuspid valveregurgitation. During surgery, a rupture of the chordattached to the anterior leaflet of the tricuspid valvewas found and the valve was replaced. The patient hadno chest anomaly nor any history of chest injury. It cantherefore be concluded that this patient experiencedisolated tricuspid valve prolapse occurred withoutdefinite basal disorder, and, to our knowledge, therehave been few such reports.