Left ventricular filling and diastolic myocardial deformation in chronic primary mitral regurgitation

Abstract

Chronic primary mitral regurgitation (MR) results in enhanced filling of the left ventricle (LV) during early diastole. Filling is impaired with the onset of LV systolic dysfunction, due to increased myocardial stiffness and reduced restoring forces. We investigated echocardiographic parameters of early diastolic function in relation to LV systolic function. Early diastolic transmitral flow and tissue Doppler velocities, propagation velocity of early filling (V(p)), and early diastolic strain rates (SR-E) were measured in 30 patients with chronic degenerative MR and 30 age-matched controls. MR subjects were further subdivided into group 1 (14 subjects) if they had well compensated LV, and group 2 (16 subjects) if they had one or more of the following: functional limitation (> NYHA class I), LV end-systolic diameter >or=4.0 cm, and LV ejection fraction <or=60%. Group 1 had increased early diastolic transmitral flow and tissue velocities, V(p) and SR-E, compared with controls. V(p) and SR-E in group 2 (46.5 +/- 9.92 cm/s and 1.44 +/- 0.36 s(-1), respectively) decreased significantly compared with group 1 (74.4 +/- 19.9 cm/s and 1.96 +/- 0.53 s(-1), P <or= 0.002). Onset and peak of early long-axis expansion and myocardial lengthening were significantly delayed in MR, and this delay was directly correlated with preload parameters. In chronic MR, novel echocardiographic measurements of early diastolic function exhibit a biphasic pattern depending on the state of LV systolic function, and may prove useful in the timing of surgery.