Influence of body size and age on maximal systolic velocity of mitral annulus motion

The maximal systolic velocity of the mitral annulus motion (or maximal syst olic long-axis contraction velocity of the ventricle, MLACV) has been sugge sted as a means to assess left ventricular function. However, reference val ues for a wide range of age and body size are lacking. The maximal systolic velocity was studied with M-mode echocardiography using the apical four- a nd two-chamber views. Data are reported as the average of the measurements of four sites of the mitral annulus. Fifty-seven healthy subjects aged 6 mo nths to 72 years were studied. In children and adolescents up to age 18, ML ACV had a significant positive correlation with age, height, body surface a rea, weight and mitral annulus motion amplitude and a significant negative correlation with heart rate. In adults, there was a significant positive co rrelation between MLACV and height, mitral annulus motion amplitude and bod y surface area and a significant negative correlation with age and heart ra te. Multiple stepwise analysis showed that the maximal systolic velocity is highly dependent on height and age in children and adolescents up to age 1 8, and on height in adults. The maximal long-axis contraction velocity (MLA CV) can be described by the following equations: MLACV (mm s(-1)) = 24.0 0.34 x height (cm) (Standard Error of the Estimate (SEE) = 10.5) in childre n and adolescents, and MLACV (mm s(-1)) = -50.5 + 0.75 x height (cm) (SEE = 9.8) in adults over 18. There were significant differences between the fou r sites, with the highest velocity at the lateral site and the lowest veloc ity at the septal site. No significant difference was found between inspira tory and expiratory beats.