MECHANICS OF DIASTOLIC SUCTION

描述(改编自申请人的摘要)：本报告的目标 研究目的是了解左心室的意义和机制。 (LV)恢复力(RF)和二尖瓣吸力流入。存在射频 当收缩末期容量(ESV)小于平衡时，就会发生吸力 音量。调查人员将在开胸时使用伺服马达系统 快速夹住左房内压(圈)在预期值的狗。 当LAP低于LV舒张压时，可防止充盈，LV 在ESV完全放松。负的完全松弛压力(FRP)表示 射频的存在。LAP=0毫米汞柱(准零源压力)，填充 完全通过吸力发生。该系统允许调查人员 通过操纵载荷将ESV与RFS(负FRP)相关联 条件。申请人表明，调查人员以前曾 描绘了充盈“生理”范围内存在的射频的大小 急性冠脉闭塞对FRP的影响。初步数据 表明1)全身和冠状动脉内(左前降支 动脉)多巴酚丁胺增加RFS和吸引流量；2)前壁 穿壁变形模式作为一种机制尤为重要 RFS；3)RFS在心动过速心衰起搏时明显受损。 调查人员现在提议更全面地描绘这一关系 与左心室扭转相关的前壁变形与RFS之间的关系 吸力。此外，调查人员将检验这一假设 胸内负压、心包束缚和心内压 流体静力梯度对RFS或吸力没有重大影响。最后的, 调查人员将开始确定这些变化的作用和机制 在RFS和吸引术中作为舒张期病理生理的组成部分 在几种过载状态下出现充盈异常。

DESCRIPTION (adapted from the applicant's abstract): The goal of this research is to understand the significance and mechanism of left ventricular (LV) restoring forces (RFs) and mitral inflow by suction. A RF is present and suction occurs when end-systolic volume (ESV) is less than equilibrium volume. The investigators will employ a servomotor system in open chest dogs which rapidly clamps left atrial pressure (LAP) at a desired value. With LAP less than LV diastolic pressure, filling is prevented and the LV fully relaxes at ESV. A negative fully relaxed pressure (FRP) indicates presence of a RF. With LAP = 0 mmHg (quasi-zero source pressure), filling occurs exclusively by suction. The system allows the investigators to relate ESV to RFs (neg FRP) an suction flow by manipulating loading conditions. The applicant indicates that the investigators have previously delineated the magnitude of RF present over "physiologic" range of filling and the effect of acute coronary occlusion on FRP. Preliminary data indicate that 1) both systemic and intra-coronary (left anterior descending artery) dobutamine increase RFs and suction flow; 2) anterior wall transmural deformation patterns are especially important as a mechanism of RFs; and 3) RFs are markedly impaired in pacing tachycardia heart failure. The investigators now propose to more completely delineate the relationship between anterior wall deformation linked to LV torsion ("twist") and RFs and suction. In addition, the investigators will test the hypothesis that negative intra-thoracic pressure, pericardial restraint and intra-cardiac hydrostatic gradients do not have a major effect on RFs or suction. Last, the investigators will begin to determine the role and mechanism of changes in RFs and suction as a component of the pathophysiology of diastolic filling abnormalities in several overload states.