Nakayama T, Wakao Y, Nemoto H, Uechi M, Kageyama T, Muto M, Takahashi M
Department of Veterinary Surgery, School of Veterinary Medicine, Azabu University, Kanagawa, Japan.
Am J Vet Res. 1996 Jun;57(6):791-7.
To examine our hypothesis that changes of the mitral valve in dogs with mitral regurgitation lead to various degrees of protrusion of the cusp in individual dogs in systole.
Assessing the mitral protrusion, using B-mode echocardiography in dogs with mitral regurgitation.
33 dogs with chronic mitral regurgitation and 40 clinically normal dogs.
The mitral valve was imaged in the right parasternal left ventricular long-axis view, and we measured the height (H) from the coaptation point or tip of the protruded cusp to the mitral annular plane. When the tip of the protruded cusp was located beyond the mitral annular plane extending into the left atrium, H was expressed as negative values.
The H in clinically normal dogs was 3.7 +/- 0.8 mm. In dogs with mitral regurgitation, the mitral cusp protruded toward the left atrium to various degrees, and H was -0.7 +/- 1.9 mm (range, 2.9 to -5.0 mm). The 2 dogs in the latter group with the lowest H (-5.0 and -4.5 mm, respectively) presented typical mitral flail on B-mode images. The indices of left atrial and ventricular dimension (left atrial dimension/aortic dimension and left ventricular end-diastolic dimension/body weight, respectively) were significantly higher than those in the clinically normal dogs and were negatively correlated with H.
The mitral valve in individual dogs with mitral regurgitation has different degrees of protrusion. The degree of protrusion might be related to the hemo-dynamic condition in mitral regurgitation.
检验我们的假设，即二尖瓣反流犬的二尖瓣变化会导致个体犬在收缩期出现不同程度的瓣叶脱垂。
使用B型超声心动图评估二尖瓣反流犬的二尖瓣脱垂情况。
33只慢性二尖瓣反流犬和40只临床正常犬。
在右胸骨旁左心室长轴视图中对二尖瓣进行成像，测量脱垂瓣叶的贴合点或尖端至二尖瓣环平面的高度（H）。当脱垂瓣叶的尖端位于二尖瓣环平面之外并延伸至左心房时，H表示为负值。
临床正常犬的H为3.7±0.8毫米。在二尖瓣反流犬中，二尖瓣瓣叶向不同程度地突向左心房，H为-0.7±1.9毫米（范围为2.9至-5.0毫米）。后一组中H最低的2只犬（分别为-5.0和-4.5毫米）在B型图像上呈现典型的二尖瓣连枷样改变。左心房和心室尺寸指标（分别为左心房尺寸/主动脉尺寸和左心室舒张末期尺寸/体重）显著高于临床正常犬，且与H呈负相关。
二尖瓣反流个体犬的二尖瓣有不同程度的脱垂。脱垂程度可能与二尖瓣反流的血流动力学状况有关。
