Phase differences between left ventricular wall motion and transmitral flow in man: evidence for involvement of ventricular restoring forces in normal rapid filling

Abstract

To assess the possible role of restoring forces underlying left ventricular wall motion during rapid filling, the time relations between left ventricular dimensions and filling velocity were studied by digitised M-mode and Doppler echocardiography in 23 normal children and 43 patients: 11 with mild and 17 with severe mitral regurgitation, and 15 with left ventricular hypertrophy due to aortic stenosis. In normal children, peak mitral flow velocity characteristically lagged peak rate of dimension increase by 50 ± 15 msec, and peak rate of posterior wall thinning by 35 ± 15 msec, ( P < 0.01 for both). Towards the apex, and along the long axis of the ventricle, these phase differences between dimension and flow velocity were not apparent. The characteristic time relations between flow velocity and transverse dimension were also present in patients with left ventricular hypertrophy or mild mitral regurgitation, but when mitral regurgitation was severe they were lost and there was no significant difference in timing between peak flow velocity and peak rate of dimension change (−2 ± 30 msec) or wall thinning (−4 ± 25 msec). We conclude that phase differences between left ventricular wall motion and mitral inflow velocity are present in the normal ventricles of children. They cannot be explained on the basis of simple shape changes or passive filling of the relaxing ventricle, but strongly suggest the additional presence of ventricular restoring forces. They persist in patients with left ventricular hypertrophy or mild mitral regurgitation, but are lost when the regurgitation is severe, the filling pattern reverting to that predicted for passive distension of the ventricular cavity by a high left atrial pressure.