We sought to study the mechanics of ventricular contraction in patients with and outward basal movement. Using echocardiographic parasternal long-axis views we retrospectively screened 760 echocardiograms to enroll 50 individuals with late systolic bileaflet prolapse, papillary muscle traction, and outward movement of the sub-annular base and posterior mitral annulus in late systole. Two-dimensional speckle tracking echocardiography was used to analyze the mechanics of contraction. Global and regional longitudinal strain values between the study group and 45 healthy control subjects were compared. The study group's global strain was lower compared to the control group. We identified a pattern of weak contraction of the inferior and lateral walls in the late systolic bileaflet prolapse group. The weakest segment in the study group was the basal-inferolateral segment (- 15.8% vs. - 21.5%, p < 0.001). There was no relationship between the mitral annular size, degree of leaflet prolapse, or degree of basal weakness. Late systolic bileaflet mitral prolapse and papillary muscle traction are accompanied by an outward movement of the sub-annular base and posterior mitral annulus in late systole. We demonstrated an abnormal contractile pattern in these ventricles characterized by a weaker contraction of the base, most significant at the inferolateral segment. This weakness of contraction may contribute to the outward movement of the base and posterior annulus.
Keywords: Abnormal ventricular contractility; Global longitudinal strain; Late systolic bileaflet prolapse; Papillary muscle traction; Regional longitudinal strain; Two-dimensional speckle tracking echocardiography.