Dynamic Changes of Right Ventricular Global Longitudinal Strain on Echocardiography in the Development of Right Ventricular Fibrosis of Experimental Piglets With Right Ventricular Pressure Overload
Objectives:To explore the dynamic changes of right ventricular global longitudinal strain (RVGLS) on echocardiography during the process of right ventricular fibrosis with right ventricular pressure overload.Methods:Animal models with RV pressure overload (n=5) were established by main pulmonary artery (PA) banding in piglets.The ratio of RV pressure to left ventricular (LV) pressure was greater than 60％ as assessed by the pressure measuring needle during the operation.Pre-and post-operative echocardiography were performed.Histopathological examination of RV tissues was performed at the end of the experiment.Results:During the establishment of the animal models,2 piglets died due to hemorrhagic shock,while 3 piglets survived and were included in the analysis.Systolic RV pressure,systolic PA pressure and mean PA pressure(measured at the proximal end of the constriction) were significantly increased immediately after PA banding,mean RV pressure and mean PA pressure were significantly inreased at 14 weeks postopseratively (all P<0.05).Tricuspid annulus plane systolic excursion and peak early diastolic velocity of tricuspid annulus (TV e') decreased immediately after operation (all P<0.05).They returned to the pre-operative level in the following three weeks.The absolute values of RVGLS were reduced after PA banding (all P>0.05).The RVGLS of the inner membrane layer began to recover after 3 weeks,and the RVGLS of the middle and outer membrane layers began to recover after 7 weeks.However,the time to peak RVGLS was significantly prolonged and could not be restored even untill the end of the experiment (14 weeks after surgery)(all P<0.05).At the end of the experiment,pathological examination revealed fibrous tissue hyperplasia in both the myocardial interstitium and endocardium.Conclusions:The measurement of intracardiac pressure and pathological results confirmed the success of the establishment of the animal model of increased right ventricular afterload.Both stress and strain cannot truly represent the intrinsic characteristics of the myocardium under pressure overload.The prolonged time to peak of longitudinal strain might indirectly reflect the progression of myocardial injury more persistently during the process of increased right ventricular afterload and myocardial injury.
global longitudinal straintime to peak strainpressure overloadright ventricular fibrosis
万方数据
维普
