CHORDAL PRESERVATION DURING MITRAL VALVE REPLACEMENT--EFFECT ON LV FUNCTION

评估弦结构的相对贡献， 二尖瓣装置对左心室功能（LVF）的影响， 存在慢性二尖瓣返流（CMR），18/26动物模型 的CMR是通过在前壁创建一个4 mm的穿孔来开发的。 二尖瓣瓣叶在心肺转流术。 完成 血流动力学、超声和放射性核素功能分析 将在对照组动物中进行， 穿孔手术的幸存者，以评估 左心室纤维化。 迄今为止获得的数据显示，存活率达到70- 80 20- 25 kg动物中，25- 30 kg动物中超过90%。 急性变化 LVF中包括dP/dt下降，而心输出量保持不变 不变 右心、左心房和楔压增加。 研究的第二阶段包括进行二尖瓣置换术， 在18只对照动物中进行MVR，其中一半将 随机分配至保留腱索组，一半随机分配至标准自体- 瓣膜移除 研究组包括CMR的随机化 这两组动物。 LV功能研究和 将获得几何结构沿着与核血管造影数据， 分析，以评估MVR期间的腱索保留是否有任何 对正常容量超负荷心室随后LVF的影响。

To assess the relative contribution of the chordal structures and mitral valve apparatus to left ventricular function (LVF), in the presence of chronic mitral regurgitation (CMR), 18/26 animal models of CMR were developed by creating a 4mm perforation of the anterior mitral valve leaflet during cardiopulmonary bypass. Complete hemodynamic, ultrasonographic, and radionuclide functional analysis will be performed on a control group of animals and in all survivors of the perforation operation to evaluate the effects of CMR on LVF. Data acquired to date show that a 70-80% survivorship was attained in 20-25kg animals, and over 90% in 25-30kg animals. Acute changes in LVF included a drop in dP/dt, while cardiac output remain unchanged. Right heart, left atrial and wedge pressure increased. The second phase of the study consists of performing mitral valve replacement (MVR) in 18 control animals, half of which will be randomized to chordal preservation and half to standard native- valve-removal. The study arm consists of randomization of the CMR animals to these same two groups. Studies of LV function and geometry along with nuclear angiographic data will be obtained and analyzed, to assess whether chordal preservation during MVR has any effect on subsequent LVF in normal volume overloaded ventricles.