Investigation of right ventricular longitudinal systolic function by velocity vector imaging

Abstract

Objective To investigate the feasibility and accuracy of velocity vector imaging(VVI)to assess strain and strain rate of right ventrieule(RV)during varying myocardial functional states.Methods VVI of the longitudinal RV were recorded in 7 closed-chest anesthetized mongrel dogs from the apical 4-chamber view during 3 different inotropic states.Peak dp/dt from the RV contraction during the right cardiac catheterization,which was used as the gold standard of RV contractility,was obtained simultaneously in each inotropic state.Peak systolic velocities(V), peak systolic strain rates(SR),peak systolic strains(S)at the basal, middle and apical segments of RV free wall and septal from the longitudinal axis were quantitatively measured by using VVI software system respectively.Results The peak systolic strain and strain rate of the longitudinal RV free wall and septal were increased with the infusion of dobutamine and decreased with the infusion of metoprolol.A significant correlation was found between peak RV dp/dt and RV mean strain and mean strain rate(r=0.79, 0.75;P <0.01).Among all RV segments, the peak systolic S,SR of RV basal free wall had the most significant correlation to peak dp/dt (r=0.83,0.78;P<0.01).Conclusions Strain rate imaging drived from VVI could quantitatively and sensitively detect the longitudinal RV contractile function.Peak systolic S and SR determined at the longitudinal RV basal free wall were the strong noninvasive indices of RV contractility. Key words: Echocardiography; Ventrieular function,Right; Strain; Strain rate