Nagata S, Sakakibara H, Beppu S, Park Y D, Matsuhisa M, Kimura E, Masuda Y, Nimura Y
J Cardiogr. 1982 Sep;12(3):779-87.
Currently, echocardiographic diagnosis of mitral valve prolapse is made when the mitral leaflets protrude into the left atrium crossing the mitral ring. However, there remains the possibility that some mitral valve prolapse, particularly mild one, is overlooked by the currently used criterion. In the present study, new echocardiographic criterion in the diagnosis of mitral valve prolapse is proposed. The criterion includes the systolic dislocation of the mitral leaflets at its coaptation zone. The validity of the new criterion is supported by the following facts. (1) Dislocation of the mitral leaflets at the coaptation zone was never observed in healthy subjects. (2) Real-time two-dimensional echocardiograms from eight cases with a midsystolic click and a late systolic murmur, the characteristic phonocardiographic findings of mitral valve prolapse, invariably demonstrated the dislocation of either the anterior or posterior mitral leaflet at the coaptation zone leading to the diagnosis of mitral valve prolapse. Four of five cases with a midsystolic click and a holosystolic murmur were also diagnosed echocardiographically as mitral valve prolapse based on the proposed criterion. However, two of the former cases and one of the latter cases did not demonstrate the protrusion of the mitral leaflets into the left atrium crossing the mitral ring, indicating inability to diagnose mitral valve prolapse based on the commonly adopted criterion. (3) Based on the extent and degree of dislocation of the coaptation of the mitral leaflets, mitral valve prolapse could be classified into nine grades. It was found that the incidence of mitral regurgitation proved by phonocardiography or angiocardiography is higher as the grade of prolapse becomes greater.
目前，当二尖瓣叶突入左心房并越过二尖瓣环时，即可通过超声心动图诊断二尖瓣脱垂。然而，仍有可能一些二尖瓣脱垂，尤其是轻度脱垂，会被目前使用的标准所忽视。在本研究中，提出了一种用于诊断二尖瓣脱垂的新超声心动图标准。该标准包括二尖瓣叶在其瓣叶闭合区的收缩期移位。以下事实支持了新标准的有效性。（1）在健康受试者中从未观察到二尖瓣叶在瓣叶闭合区的移位。（2）对8例伴有收缩中期喀喇音和收缩晚期杂音（二尖瓣脱垂的典型心音图表现）的患者进行实时二维超声心动图检查，均显示二尖瓣前叶或后叶在瓣叶闭合区移位，从而诊断为二尖瓣脱垂。根据所提出的标准，5例伴有收缩中期喀喇音和全收缩期杂音的患者中有4例也通过超声心动图诊断为二尖瓣脱垂。然而，前一组中的2例和后一组中的1例并未显示二尖瓣叶突入左心房并越过二尖瓣环，这表明根据常用标准无法诊断二尖瓣脱垂。（3）根据二尖瓣叶瓣叶闭合处移位的范围和程度，二尖瓣脱垂可分为9级。研究发现，经心音图或心血管造影证实的二尖瓣反流发生率随着脱垂程度的增加而升高。
