Miki S, Murakami T, Iwase T, Tomita T, Nakamura Y, Kawai C
Department of Internal Medicine, Kyoto University Hospital, Japan.
J Am Coll Cardiol. 1991 Jun;17(7):1507-16. doi: 10.1016/0735-1097(91)90639-q.
Doppler echocardiographic transmitral peak early velocity normalized to the time-velocity integral during diastole is equivalent to volumetric peak filling rate normalized to stroke volume. To compare the pathophysiologic validity of normalized and nonnormalized peak early flow velocity, pulsed Doppler echocardiography with simultaneous high fidelity left ventricular pressure measurements was performed in 52 patients with coronary artery disease. Left ventricular loading conditions were changed by intravenous administration of norepinephrine in 15 patients and synthetic atrial natriuretic polypeptide in 15 others. Norepinephrine increased nonnormalized and normalized peak early flow velocities in association with significantly elevated end-diastolic, peak systolic and mitral valve opening pressures and decelerated the time constant of left ventricular isovolumetric pressure decline. Atrial natriuretic polypeptide did not change either nonnormalized or normalized peak early flow velocity, despite significant reductions in end-diastolic, peak systolic and mitral valve opening pressure and an accelerated time constant. Normalized peak early flow velocity showed the highest univariate correlation with long-term change in mitral valve opening pressure (n = 52, r = 0.67, p less than 0.0001). It provided a modest univariate correlation (n = 30, r = 0.74, p less than 0.0001) with immediate change in mitral valve opening pressure during norepinephrine infusion, whereas this correlation was lower (n = 30, r = 0.57, p less than 0.001) during polypeptide infusion. However, multivariate regression analysis relating normalized peak velocity with long- and short-term changes in end-diastolic, peak systolic and mitral valve opening pressures, time constant and constant of left ventricular chamber stiffness improved the correlation coefficients (r = 0.80 to 0.85, all p less than 0.0001). In contrast, neither univariate nor multivariate correlations of nonnormalized velocity with long- and short-term changes in these hemodynamic variables were satisfactory. Thus, nonnormalized peak early flow velocity does not directly reflect underlying hemodynamic changes in humans. Normalization to mitral stroke volume clarifies the dependence of peak early flow velocity on the determinants of early diastolic filling. When left ventricular early diastolic filling is evaluated by Doppler echocardiography, normalized peak early flow velocity should be taken into consideration.
舒张期经二尖瓣血流早期峰值速度与舒张期时间 - 速度积分的比值，等同于容积峰值充盈率与每搏输出量的比值。为比较标准化和未标准化的早期峰值血流速度在病理生理学上的有效性，对52例冠心病患者进行了脉冲多普勒超声心动图检查，并同步进行高保真左心室压力测量。15例患者静脉注射去甲肾上腺素，另15例静脉注射合成心房利钠多肽，以改变左心室负荷状态。去甲肾上腺素增加了未标准化和标准化的早期峰值血流速度，同时舒张末期、收缩期峰值和二尖瓣开放压力显著升高，并使左心室等容压力下降的时间常数减慢。尽管舒张末期、收缩期峰值和二尖瓣开放压力显著降低，且时间常数加快，但心房利钠多肽并未改变未标准化或标准化的早期峰值血流速度。标准化的早期峰值血流速度与二尖瓣开放压力的长期变化具有最高的单变量相关性（n = 52，r = 0.67，p < 0.0001）。在去甲肾上腺素输注期间，它与二尖瓣开放压力的即时变化具有适度的单变量相关性（n = 30，r = 0.74，p < 0.0001），而在多肽输注期间，这种相关性较低（n = 30，r = 0.57，p < 0.001）。然而，将标准化峰值速度与舒张末期、收缩期峰值和二尖瓣开放压力的长期和短期变化、时间常数以及左心室腔刚度常数进行多元回归分析，提高了相关系数（r = 0.80至0.85，所有p < 0.0001）。相比之下，未标准化速度与这些血流动力学变量的长期和短期变化的单变量及多变量相关性均不令人满意。因此，未标准化的早期峰值血流速度不能直接反映人体潜在的血流动力学变化。以二尖瓣每搏输出量进行标准化，阐明了早期峰值血流速度对舒张早期充盈决定因素的依赖性。当通过多普勒超声心动图评估左心室舒张早期充盈时，应考虑标准化的早期峰值血流速度。
