Thomas J D, Choong C Y, Flachskampf F A, Weyman A E
Noninvasive Cardiac Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
J Am Coll Cardiol. 1990 Sep;16(3):644-55. doi: 10.1016/0735-1097(90)90356-t.
Left ventricular filling (as assessed by Doppler echocardiography) has previously been shown to depend in a complex fashion on ventricular diastolic function (compliance and relaxation) as well as other variables, such as atrial pressure and compliance, ventricular systolic function and mitral valve impedance. To study the effect of isolated physiologic alterations on individual Doppler indexes, a mathematic model of mitral flow was analyzed. By varying one physiologic variable at a time, it was shown that mitral velocity acceleration is affected directly by atrial pressure and inversely by the ventricular relaxation time constant, with relatively little impact of chamber compliance. Deceleration rate was directly influenced by mitral valve area, atrial pressure and ventricular systolic dysfunction and inversely affected by atrial and ventricular compliance relations, with little impact of relaxation unless it was so delayed as to be incomplete during deceleration. Peak velocity was directly affected most strongly by initial left atrial pressure, and lowered somewhat by prolonged relaxation, low atrial and ventricular compliance and systolic dysfunction. Strikingly different filling patterns emerged when the primary physiologic alterations were accompanied by simultaneous compensatory changes in atrial pressure designed to maintain stroke volume constant. Low ventricular compliance with preload compensation produced characteristic E waves with very short acceleration and deceleration times and high peak velocity. Thus, mathematic analysis of ventricular filling helps to explain the physical and physiologic basis for the transmitral velocity curve.
先前的研究表明，左心室充盈（通过多普勒超声心动图评估）以复杂的方式取决于心室舒张功能（顺应性和松弛）以及其他变量，如心房压力和顺应性、心室收缩功能和二尖瓣阻抗。为了研究孤立的生理改变对各个多普勒指标的影响，我们分析了二尖瓣血流的数学模型。通过一次改变一个生理变量，结果显示二尖瓣速度加速度直接受心房压力影响，与心室松弛时间常数呈反比，而腔室顺应性的影响相对较小。减速速率直接受二尖瓣面积、心房压力和心室收缩功能障碍的影响，与心房和心室顺应性关系呈反比，除非在减速过程中松弛延迟到不完全，否则松弛的影响很小。峰值速度最直接受初始左心房压力的强烈影响，长时间的松弛、低心房和心室顺应性以及收缩功能障碍会使其有所降低。当主要生理改变伴随着心房压力的同时代偿性变化以维持每搏量恒定时，会出现截然不同的充盈模式。低心室顺应性并伴有前负荷代偿会产生特征性的E波，其加速和减速时间非常短，峰值速度很高。因此，对心室充盈的数学分析有助于解释二尖瓣速度曲线的物理和生理基础。
