Corin W J, Murakami T, Monrad E S, Hess O M, Krayenbuehl H P
Philadelphia Heart Institute, Presbyterian Medical Center, PA 19104.
Circulation. 1991 Mar;83(3):797-807. doi: 10.1161/01.cir.83.3.797.
In chronic mitral regurgitation, the myocardium responds to the increased filling volume by geometric alteration and eccentric hypertrophy. This study was designed to evaluate the effects of a pure volume overload on left ventricular diastolic chamber and myocardial properties and to assess the relation of passive diastolic function to systolic ejection performance.
By use of simultaneous cineangiography and left ventricular micromanometry, left ventricular passive diastolic stiffness was evaluated in nine normal controls (group 1), 14 patients with chronic mitral regurgitation and a normal ejection fraction (greater than or equal to 57%, group 2), and 13 patients with mitral regurgitation and a reduced ejection fraction (less than 57%, group 3). Passive diastolic function was evaluated by using a three-constant elastic model. Left ventricular chamber properties were represented by the relation of pressure to volume; myocardial properties were evaluated by relating myocardial midwall stress to midwall strain. The constant of left ventricular chamber stiffness was decreased in group 2 compared with controls (p less than 0.05) but it was normal in group 3. The constant of myocardial stiffness was increased in group 3 compared with groups 1 and 2 (p less than 0.01). Among patients with mitral regurgitation, there was a significant inverse relation between ejection fraction and the constant of myocardial stiffness (r = -0.83).
The chronic adaptation to volume overload in chronic mitral regurgitation tends to decrease left ventricular chamber stiffness. Patients with mitral regurgitation and a depressed ejection fraction demonstrated diastolic myocardial dysfunction. Compromised diastolic function in patients with chronic mitral regurgitation and reduced systolic performance may contribute to the clinical manifestations of congestive heart failure.
在慢性二尖瓣反流中，心肌通过几何形态改变和离心性肥厚来应对增加的充盈量。本研究旨在评估单纯容量负荷过重对左心室舒张期腔室和心肌特性的影响，并评估被动舒张功能与收缩期射血性能之间的关系。
通过同步电影血管造影和左心室微测压法，对9名正常对照者（第1组）、14名慢性二尖瓣反流且射血分数正常（大于或等于57%，第2组）的患者以及13名二尖瓣反流且射血分数降低（小于57%，第3组）的患者进行左心室被动舒张硬度评估。采用三常数弹性模型评估被动舒张功能。左心室腔室特性用压力与容积的关系表示；心肌特性通过心肌中层壁应力与中层壁应变的关系进行评估。与对照组相比，第2组左心室腔室硬度常数降低（p<0.05），但第3组正常。与第1组和第2组相比，第3组心肌硬度常数增加（p<0.01）。在二尖瓣反流患者中，射血分数与心肌硬度常数之间存在显著的负相关（r = -0.83）。
慢性二尖瓣反流中对容量负荷过重的慢性适应性变化倾向于降低左心室腔室硬度。二尖瓣反流且射血分数降低的患者表现出舒张期心肌功能障碍。慢性二尖瓣反流且收缩功能降低的患者舒张功能受损可能导致充血性心力衰竭的临床表现。
