Application of color Doppler M-mode echocardiography in the assessment of ventricular diastolic function: Potential for quantitative analysis

Color Doppler M-mode echocardiography provides a spatiotemporal map of blood distribution (v(s,t)) within the heart, with a typical temporal resolution of 5 ms, a spatial resolution of 300 μm, and a velocity resolution of 3 cm/s. M-mode echocardiographic data can be obtained along a streamline from the mid-left atrium to the mid-left ventricle from either the apical transthoracic window or the basal transesophageal window. A key parameter of the color Doppler M-mode is the transmitral propagation velocity, the slope of the leading edge of the M-mode derived E-wave. This propagation velocity is significantly less than the velocities measured within the E-wave by pulsed Doppler echocardiography and appears to provide important independent information about left ventricular filling pressures and diastolic function. Furthermore, color M-mode velocities can be processed quantitatively by the Euler equation to yield estimates of the small (< 2 mmHg) pressure gradients between the base and apex during filling, the first time such gradients have been measured noninvasively.