Origin of regional pressure gradients in the left ventricle during early diastole.
Origin of regional pressure gradients in the left ventricle during early diastole.
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舒张早期左心室区域压力梯度的起源。
DOI：
10.1152/ajpheart.1995.268.2.h550
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Yellin,EL
中科院分区：
文献类型：
--
作者：
Nikolic,SD;Feneley,MP;Pajaro,OE;Rankin,JS;Yellin,EL
用于评价左心室舒张功能的左心室（LV）压力（P）-直径、LVP-面积或LVP-容积关系假定LV壁运动均匀且LVP恒定。与这些假设相反，在LV的不同部位同时测量的心室动态几何形状和LV压力存在显著差异，特别是在早期心室收缩期。我们用三对正交超声晶体（前-后和无隔壁短轴和基底-心尖长轴）和两个微压计（心尖和LV基底）对六只麻醉开胸犬进行了仪器化。在标准心肺转流期间，将二尖瓣封堵器植入二尖瓣环。在11例短暂性腔静脉闭塞期间记录数据。每隔6-8次心搏，闭塞二尖瓣1次，造成非充盈性二尖瓣狭窄。随着左心室收缩末期容积（Ves）降低至平衡容积Veq（LVP = 0时完全舒张的左心室容积）以下;非充盈性搏动中的最小负LVP增加，充盈性和非充盈性搏动中的心室形状更接近椭圆形，无论是否存在充盈，LVP最小值时的基底-心尖压差均增加。因此，在等容舒张和早期舒张期间的异质性心肌应力导致心室形状改变、心室内腔室容积重新分布、局部血液加速和相关的心室内LVP梯度。弹性回缩的作用在Ves小于Veq时具有更大的重要性，此时左心室在等容舒张期间的形状变得更加椭圆形，进而导致更大的形状变化和更大的LVP梯度。
Left ventricular (LV) pressure (P)-diameter, LVP-area, or LVP-volume relationships used to evaluate LV diastolic function assume uniform LV wall motion and constant LVP. Contrary to these assumptions, there are significant differences in ventricular dynamic geometry and in LV pressures measured simultaneously in different parts of the LV, particularly during early diastole. We instrumented six anesthetized open-chest dogs with three pairs of orthogonal ultrasonic crystals (anterior-posterior and septal-free wall minor axes, and base-apex major axis) and two micromanometers (in the apex and in the LV base). The mitral valve occluder was implanted during standard cardiopulmonary bypass in the mitral annulus. Data were recorded during 11 transient vena caval occlusions. The mitral valve was occluded for 1 beat every 6–8 beats during each vena caval occlusion to produce nonfilling diastole. With the decrease of the LV end-systolic volume (Ves) below the equilibrium volume Veq (volume of the completely relaxed LV at LVP = 0); the minimum negative LVP in nonfilling beats increases, the shape of the ventricle is more ellipsoidal in both filling and nonfilling beats, and the base-to-apex pressure gradient at the time of LVP minimum increases regardless of the presence or absence of filling. Thus heterogeneous myocardial stresses during isovolumic relaxation and early diastole result in ventricular shape changes, intraventricular redistribution of chamber volume, local accelerations of blood, and associated intraventricular LVP gradients. The role of elastic recoil assumes greater importance at Ves smaller than Veq, when the left ventricle becomes more ellipsoidal in shape during isovolumic relaxation, leading, in turn, to greater shape changes and greater LVP gradient.