異常筋束を有する閉塞性肥大型心筋症に対し異常筋束および中隔心筋切除を行った1例

Hypertrophic Obstructive Cardiomyopathy Associated with Apical-basal Muscle Bundle Treated by Extended Septal Myectomy and Surgical Excision of a Muscle Bundle：Report of a Case

はじめに　閉塞性肥大型心筋症や乳頭筋付着異常に伴う左室流出路狭窄では，Morrow手術などの中隔心筋切除をはじめとする左室流出路拡大術がよい適応となるが，僧帽弁前尖収縮期前方運動（SAM）により，僧帽弁へも手術介入を要することがある1，2）．われわれは僧帽弁への手術介入を念頭におきながらも回避することができたため，文献的報告を交えて報告する．

A 74-year-old woman was diagnosed with obstructive hypertrophic cardiomyopathy and symptoms of heart failure. Transthoracic echocardiography and other imaging examinations revealed an apical-basal muscle bundle caused by a left ventricular outflow tract （LVOT） obstruction. The peak velocity was 6.1 m/s, recorded during the Valsalva maneuver, and mitral regurgitation progressed from trivial to moderate. The course of operative treatment consisted of surgical intervention in the mitral valve. The LVOT revealed an apical-basal muscle bundle, approximately 6 mm in diameter；however, this was excluded. Extended septal myectomy and intraoperative transesophageal echocardiography were performed, the latter to verify the systolic anterior motion of the mitral valve；however, mitral regurgitation was not detected. The post-operative peak velocity improved to 2.5 m/s. In conclusion, surgical treatment of obstructive hypertrophic cardiomyopathy and LVOT obstruction associated with an apical-basal muscle bundle was performed with accurate diagnosis, thus avoiding valvular surgery.