Yamamoto K, Masuyama T, Tanouchi J, Uematsu M, Doi Y, Naito J, Hori M, Tada M, Kamada T
First Department of Medicine, Osaka University School of Medicine, Japan.
J Am Coll Cardiol. 1993 Mar 1;21(3):662-72. doi: 10.1016/0735-1097(93)90099-m.
This study was designed to assess whether the transmitral flow velocity pattern provides an estimation of left atrial pressure irrespective of the presence of left ventricular systolic dysfunction and, if not, to clarify the mechanism.
The pulsed Doppler transmitral flow velocity pattern, particularly peak early diastolic filling velocity, has been shown to change in parallel with left atrial pressure. However, extremely elevated left atrial pressure in association with heart failure does not necessarily cause an increase in peak early diastolic filling velocity in patients.
Left atrial pressure was elevated with intravenous saline infusion in 11 dogs (normal left ventricular function group) and hemodynamic, transesophageal Doppler echocardiographic and M-mode echocardiographic variables were recorded at three different loading levels. In another 12 dogs, left atrial pressure was elevated by production of left ventricular systolic dysfunction with the stepwise injection of microspheres into the left coronary artery (left ventricular dysfunction group) and the same set of recordings was obtained at three different levels of dysfunction.
Peak early diastolic filling velocity increased with left atrial pressure in the normal left ventricular function group and correlated with mean left atrial pressure (r = 0.61, p < 0.01) and early diastolic left atrial to left ventricular crossover pressure (r = 0.71, p < 0.01). In contrast, peak early diastolic filling velocity did not increase with left atrial pressure in the left ventricular dysfunction group and did not correlate with mean left atrial pressure (r = -0.05) or the crossover pressure (r = 0.06). Peak early diastolic filling velocity correlated well with the difference between the crossover pressure and left ventricular minimal pressure in the left ventricular dysfunction group (r = 0.64, p < 0.01). In contrast to peak early diastolic filling velocity, deceleration time of the early diastolic filling wave correlated with mean left atrial pressure and the crossover pressure irrespective of the primary cause of preload alteration (r = -0.54, r = -0.59, p < 0.01 respectively, n = 69 for all data).
Preload dependency of the Doppler transmitral flow velocity pattern is hampered if an increase in left atrial pressure is due to left ventricular systolic dysfunction. In this setting, the increase in left ventricular minimal pressure due to left ventricular systolic dysfunction cancels the effect of the increase in left atrial pressure on the flow velocity pattern.
本研究旨在评估二尖瓣血流速度模式是否能在不考虑左心室收缩功能障碍的情况下估算左心房压力，若不能，则阐明其机制。
脉冲多普勒二尖瓣血流速度模式，尤其是舒张早期峰值充盈速度，已被证明与左心房压力平行变化。然而，心力衰竭患者中左心房压力极度升高并不一定会导致舒张早期峰值充盈速度增加。
通过静脉输注生理盐水使11只犬（左心室功能正常组）的左心房压力升高，并在三个不同负荷水平记录血流动力学、经食管多普勒超声心动图和M型超声心动图变量。在另外12只犬中，通过向左冠状动脉逐步注射微球导致左心室收缩功能障碍来升高左心房压力（左心室功能障碍组），并在三个不同功能障碍水平获得相同的记录。
在左心室功能正常组中，舒张早期峰值充盈速度随左心房压力升高而增加，并与平均左心房压力（r = 0.61，p < 0.01）和舒张早期左心房与左心室交叉压力（r = 0.71，p < 0.01）相关。相比之下，在左心室功能障碍组中，舒张早期峰值充盈速度并未随左心房压力升高而增加，且与平均左心房压力（r = -0.05）或交叉压力（r = 0.06）无关。在左心室功能障碍组中，舒张早期峰值充盈速度与交叉压力和左心室最小压力之间的差值密切相关（r = 0.64，p < 0.01）。与舒张早期峰值充盈速度不同，舒张早期充盈波的减速时间与平均左心房压力和交叉压力相关，而与前负荷改变的主要原因无关（分别为r = -0.54，r = -0.59，p < 0.01，所有数据n = 69）。
如果左心房压力升高是由于左心室收缩功能障碍所致，则二尖瓣血流速度模式的前负荷依赖性会受到影响。在这种情况下，左心室收缩功能障碍导致的左心室最小压力升高抵消了左心房压力升高对血流速度模式的影响。
