腱索断裂により"Murmur on top of the head"を呈した僧帽弁閉鎖不全症の1治験例

A case of "Murmur on top of the head" in mitral regurgitation due to ruptured chordae tendineae

　腱索断裂による僧帽弁閉鎖不全症（以下MR）は，最近心エコー図法の発達により高頻度に診断され，断裂部位までも明らかにされるようになった。しかし，心音図によってもその雑音の性質，放散方向に特徴ある所見が得られる。

　我々は腱索断裂により"murmur on top of the head"を呈したMRの1例を経験したので報告する。この症候群については，1967年Merendinoら^1）によって紹介されて以来その存在は有名であるが，報告例は少なく稀なものと考えられる。

A 52-year-old house wife was admitted to our department with exertional dyspnea and pretibial edema. She has no history of rheumatic fever, infec-tive endocarditis or trauma, and was pointed out a heart murmur on medical check-up 8 years prior to the admission. Mild dyspnea and pretibial edema have developed since 3 years.

Physical examination on admission revealed no cyanosis, no venous dilatation nor hepatomegaly, but has minimal rales and pretibial edema. Her blood pressure was 112/62 mmHg, heart rate was 75/min with regular sinus rhythm. On precordial palpation, the apical impulse was felt in sustained fashion at the middle anterior axillary line and seventh intercostal space, and a thrill was present over the aortic area and the apex, and a left atrial impulse was also palpable. On auscultation, a grade 5/6 apical pansystolic, diamond-shaped and harsh murmur was heard, and was radiated to the axilla, scapulae, neck, left hemithorax and paravertebral area. The murmur was clearly heard even on the top of the head and peripheral parts of the body conducted by spinal column and bones.

The electrocardiogram showed normal sinus rhy-thm and left ventricular hypertrophy with left atrial overload. Moderate left atrial and left ventricular enlargements were noted on the chest roentgeno-gram. M-mode as well as two-dimensional echocar-diograms showed abnormal intra-atrial echo, ante-rior leaflet prolapse and incomplete coaptation of the mitral leaflets.

Cardiac catheterization showed increased pulmo-nary wedge pressure and moderate pulmonary arterial hypertension. Angiography disclosed severe mitral regurgitation (grade III by Sellers' classifica-tion).

Mitral regurgitation due to ruptured chordae tendineae, therefore, became evident, then, mitral valve replacement was successfully performed, and torn chordae tendineae of the anterior mitral leaflet were found. The postoperative course was favorable.

Clinical importance of the "Murmur on Top of the Head" was discussed with understanding ana-tomical and hemodynamical interrelations between radiation of the murmurs and type of mitral regur-gitation.