Quantitative assessment of diastolic filling function: a new Doppler echocardiographic method and in vitro validation

The effects of changes in preload and chamber compliance on the transmitral flow pattern was investigated with a fluid dynamics model. A decrease in compliance led to a steepening of the deceleration slope and a shortening of the pressure half-time in both restricted and nonrestricted valves. An increase in the preload led to a longer pressure half-time but did not affect the slope in the restricted valve. However, increased preload led to a shorter pressure half-time and a steeper slope in the nonrestricted valve. A mathematically derived method to measure the net atrioventricular compliance (-[annular area] va/[pvt [flow deceleration rate]]), where va and vt are flow velocities at the mitral anulus and the mitral tip levels) was then proposed. The values obtained by this method showed a strong correlation with true values (r2 = 0.89). A possibility of noninvasive quantitative assessment of diastolic filling function was implied.