Noonan症候群に伴う閉塞性肥大型心筋症に対して中隔心筋切除術を施行した1例

Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy Due to Noonan Syndrome；Report of a Case

はじめに　Noonan症候群は特徴的な顔貌，先天性心疾患，低身長，知的障害などを示す先天性遺伝子疾患である．Noonan症候群では肺動脈弁狭窄症や肥大型心筋症（HCM）をはじめとした心疾患を合併するが，小児の閉塞性HCM（HOCM）に対する手術報告はまれである．われわれは15歳のNoonan症候群男児におけるHOCMに対して外科的心筋切除術を行い，良好な結果を得たので報告する．

A 15-year-old boy with Noonan syndrome, who had been diagnosed with hypertrophic cardiomyopathy （HCM） at 4 and treated by drugs, was referred to our hospital because of progression of left ventricular outflow tract obstruction （LVOTO）. Transthoracic echocardiogram （TTE） revealed left ventricular hypertrophy （LVH）, LVOTO （systolic gradient：102 mmHg）, and systolic anterior motion of the mitral valve （SAM） with mild mitral regurgitation （MR）. We performed septal myectomy by transaortic and transapical approaches. Postoperative TTE revealed significant reduction in left ventricular outflow tract （LVOT） gradient （9 mmHg）, resolution of SAM, and reduction in MR grade. The postoperative course was uneventful except for transient atrial tachyarrhythmia. Myectomy for HCM in a patient with Noonan syndrome is rare. This case suggests that myectomy is useful for the patients with Noonan syndrome.