Yellin E L, Yoran C, Sonnenblick E H, Gabbay S, Frater R W
Circ Res. 1979 Nov;45(5):677-83. doi: 10.1161/01.res.45.5.677.
We designed this study to test the hypothesis that in acute mitral regurgitation the mitral regurgitant area (MRA) is a dynamic quantity which varies with the time variation of ventricular volume. Mitral insufficiency was created in five open-chest dogs in which a portion of the anterior leaflet was excised. Phasic aortic and mitral flows were measured electromagnetically, along with left atrial and ventricular pressures. Filling, regurgitant, and stroke volumes, and systolic pressure gradient were determined by digital methods. MRA was calculated from the fluid dynamic equation of motion to give the temporal mean and the instantaneous value at three instants of time and at the time of peak flow (when inertia is negligible). Mean regurgitant fraction was 42 +/- 12% with no indication of left ventricular failure due to volume overload. MRA decreased monotonically with time to 59% of its initial value and closely paralleled the decrease in ventricular volume during systole. In a control study using a tilting-disc prosthesis with a hole 5 mm in diameter in the occluder, the calculated MRA was time invariant and equal to the measured area for regurgitation. We conclude that in acute mitral regurgitation the MRA is a function of ventricular volume.
我们设计了这项研究，以检验以下假设：在急性二尖瓣反流中，二尖瓣反流面积（MRA）是一个动态量，它会随心室容积的时间变化而改变。我们对五只开胸犬造成二尖瓣关闭不全，切除了部分前叶。通过电磁法测量主动脉和二尖瓣的时相血流，同时测量左心房和心室压力。通过数字方法确定充盈量、反流量、每搏量和收缩压梯度。根据流体动力学运动方程计算MRA，得出三个时间点以及流量峰值时（此时惯性可忽略不计）的时间平均值和瞬时值。平均反流分数为42±12%，没有因容量超负荷导致左心室衰竭的迹象。MRA随时间单调下降至其初始值的59%，并且在收缩期与心室容积的下降密切平行。在一项对照研究中，使用一个在封堵器上有一个直径5毫米孔的倾斜盘式人工瓣膜，计算得出的MRA不随时间变化，且等于测量的反流面积。我们得出结论，在急性二尖瓣反流中，MRA是心室容积的一个函数。
