左室ペーシングの併用により術後心不全を脱却し，遠隔期には著明な心機能改善が得られた2弁置換術の1治験例

A Case of Aortic and Mitral Valve Replacement in a Patient who Recovered from Heart Failure after an Operation using Left Ventricular Pacing,and who Showed Marked Improvement of Left Ventricular Contractile Function and Reverse Remodeling

要旨　患者は75歳，男性．著明な心機能低下と左室拡大を呈し，高度大動脈弁逆流と二次性僧帽弁逆流に対し2弁置換術を施行．高度房室ブロックを来し，右室ペーシングで経過観察するも，術後に低心拍出状態が持続した．心外膜心筋電極を用いた左室ペーシングを開始し，術後心不全から速やかに脱却できた．さらに術半年後には極めて顕著な心機能改善(左室駆出率35→65%)と左室径の縮小(左室収縮末期径68→46mm)が得られた．弁逆流例では心室容量負荷による不可逆的心筋障害出現前の弁置換術が推奨され，従来心室径および駆出率が簡便な指標として汎用されてきた．しかし，本例では旧来の概念で不可逆的とさえ判断される心室の状況を呈しながら，2弁置換術により正常心機能にまで著明な心室逆リモデリングを認めたことから，弁逆流症における弁置換術施行の適正時期を再考させる貴重な1治験例であった．

Summary

　A 75-year-old male underwent double valve replacement(DVR) for severe aortic regurgitation(AR) and secondary mitral regurgitation(MR), in the presence of marked contractile dysfunction and left ventricular dilatation. He had complete atrioventricular(AV) block during the operation, and was unable to recover from low output heart failure with right ventricular pacing. However, using left ventricular(LV) pacing, he quickly recovered and after six months, marked improvement of LV contractile function〔LV ejection fraction(LVEF) 35→65%〕 and reverse remodeling〔LV end systolic diameter(LVDs) 68→46mm〕 was obtained.

　Early valve replacement has been recommended for regurgitation before irreversible myocardial dysfunction is able to occur due to volume overload. LVEF and LV diameters have been used as useful indexes for the timing of the operation.

　From the point of view of these previous indexes, this case might be thought to have had irreversible myocardial damage, but tremendous reverse remodeling was shown and sufficient cardiac function equal to normal performance was obtained after DVR. This clinical course has led us to reconsider the appropriate timing of valve replacement for regurgitation.