Preliminary study on new parameter of myocardial elasticity

Objective To discuss the value of the new parameter of myocardial elasticity derived from circumferential strain.Methods Right ventrieular apical pacing was established on the beagle dogs.Before and after pacing,the peak of early diastolic flow velocity (E peak),peak of atrial flow velocity (A peak),and the ratio of A/E were measured.The peak pressure-rise rate (+ dp/dtmax),peak pressure-fall rate (-dp/dt max),left ventricular systolic pressure(LVSP),LV diastolic pressure(LVDP)were measured by cardiac catheterization.The circumferential strain at the levels of base (CSRA),papillary (CSPM) and cardiac apex (CSAP) were measured,and the parameter of myocardial clasticity at the levels of base (EBA),papillary (EPM) and cardiac apex (EAP) were measured and calculated,respectively.Results ①After pacing,the + dp/dt and LVDP were increased,but the-dp/dtmax was decreased (P ＜0.05).② After pacing,the CSPM and CSAP were all decreased,but EBA,EPM,EA were all increased(P ＜0.05).③ The areas under the receiver operating characteristic curves (ROC) of CSAP,CSPM,EAP,EPM and EBA were all 1,and the area under the curve of CSBA was 0.687.EAB,EPM and EAP were significant negative correlation with CSPM and CSAP,but are positive correlated with A/E and LVDP (P ＜ 0.05).Conclusions The parameter of myocardial elasticity derived from circumferential strain includes useful information about myocardial deformation and function.The new parameter can be applied to assess the diastolic function of left ventricle. Key words: Echocardiography; Cardiac pacing,artificial; Ventricular function,left; Elasticity; Strain