Doppler Evaluation of Left Ventricular Diastolic Inflow and Outflow Waveforms in Normal Subjects

The measurements of the left ventricular inflow parameters do not necessarily reflect the measurements of the respective outflow ones. The A wave transit time from the mitral valve to the left ventricular outflow tract has been demonstrated to have a fair correlation with measures of the left ventricular late diastolic stiffness. We performed this study to obtain the normal patterns of the diastolic left ventricular outflow as well as inflow waveforms and to evaluate the roles of aging and other physiological parameters in their evolution. The study population consisted of 60 healthy subjects (aged 22-66 years). They were divided into three groups: group 1 (aged 20-34 years), group 2 (aged 35-49 years), and group 3 (aged 50-70 years). Pulse-wave Doppler echocardiography was performed to get the patterns of diastolic left ventricular inflow and outflow waveforms. With aging, the peak velocity and velocity-time integral of the transmitted transmitral E wave decreased, and those of the transmitted transmitral A wave increased with a progressive decrease in their ratio of transmitted transmitral E to A wave. The diastolic left ventricular inflows followed a similar aging course. There was no obvious aging trend in the A wave transit time from the mitral valve to the left ventricular outflow tract. Multiple linear regression analyses selected age as the most important determinant in the differences in most left ventricular inflow and outflow indices among normal subjects. Besides, heart rate had modest influences on some Doppler indices. This study confirms the age related changes in the left ventricular inflow waveforms and further establishes the concept that the diastolic left ventricular outflow waveforms are also significantly influenced by age and heart rate. Hence, both factors should be taken into account in interpreting the diastolic left ventricular outflow as well as inflow indices.