Assessment Of Right Ventricular Function By Strain And Strain Rate Imaging After Transcatheter Closure Of Atrial Septal Defect

Objective This study was done to evaluate the changes of the right heart dimension, systolic function and regional myocardial contractility using conventional echocardiography and strain as well as strain rate imaging before and after transcatheter closure of atrial septal defect(ASD),and to discuss its clinical value.Methods 33 patients with ASD(mean age 26.47±12.34 years,8 male,25 female) were diagnosed as secundum ASD in the First Affiliated Hospital of Kunming Medical College,and all had been successfully received Amplatzer septal occluder(ASO).They were scanned by conventional echocardiography and dynamic tissue velocity imaging(TVI)before and after the three days and three months undergoing transcatheter closure of ASD.Besides,twenty healthy volunteers(mean age 26.25±12.57 years,4 male,16 female)were selected as control group.①Regional myocardial contractility of right ventricle(RV)were measured by strain and strain rate.The dynamic tissue velocity imaging(TVI)were obtained at apical four-chamber view.Septal and right free walls were divided into basal,mid and apical segments respectively.The systolic peak strain(ε)and strain rate(SR)were measured at basal and mid segments before and after transcatheter closure of ASD and compared with that of the controls.②The diameters of RA and RV was measured.The end-diastolic anterior-posterior diameter of RV was measured at the parasternal long axis view of left ventricle.The end-diastolic fluctuate diameter and left-right diameter of RV,and end-systolic fluctuate and left-right diameter of RA were measured at the apical four-chamber view.③The main pulmonary artery diameter and pulmonary artery systolic pressure were measured.The main pulmonary artery diameter(MPA)was measured at the parasternal aortic short axis view.The pulmonary artery systolic pressure(PASP)was evaluated by peak velocity of tricuspid regurgitation,using continuous wave Doppler at the apical four-chamber view.④Right ventricle volume and function were calculated.Right ventricular end-systolic volume(RVESV), end-diastolic volume(RVEDV),stroke volume(RVSV)and ejection fraction(RVEF) were calculated with Simpson method at the apical four-chamber view.Results Thirty-three patients received transcatheter closure of ASD were examined before and after the three days and three months.①Peak systolic strain and strain rate of the mid segment in right free wall are higher than that of the basal segment in controls(P＜0.05).Compared with the control group,the peak systolic strain and strain rate of mid and basal segments in right free wall in ASD group increased significantly(P＜0.05).Peak systolic strain and strain rate of the mid and basal segments in right free wall and interventricular septal before and after transcatheter closure of ASD were not significantly different(P＞0.05).②Compared with the diameters before ASD closure,the end-diastolic fluctuate diameter and left-right diameter of RA,the end-diastolic anterior-posterior diameter and left-right diameter of RV decreased significantly(P＜0.05)after three days.The end-diastolic fluctuate diameter of RV did not decrease significantly(P＞0.05)after three days,but the diameter decreased significantly(P＜0.05)after three months.Compared with the diameters after three days,the end-systolic fluctuate diameter and left-right diameter of RA,the end-diastolic anterior-posterior diameter and left-right diameter of RV decreased significantly(P＜0.05)after three month.③Compared with the diameter before ASD closure,the main pulmonary artery diameter did not decreased(P＞0.05) after three days,but the diameter decreased significantly(P＜0.05)after three month. Compared with that before ASD closure,the pulmonary artery systolic pressure decreased significantly(P＜0.05)after the three days and three months.But the pulmonary artery systolic pressure three months later is not lower signifcantly than that three clays later(P＞0.05).④Compared with the values before ASD closure, RVESV,RVEDV and RVEF reduced significantly(P＜0.05)after three days,however, RVESV did not reduce(P＞0.05).After three months RVEDV,RVESV,RVSV,and RVEF reduced more significantly than that before ASD closure(P＜0.05).After three months RVEDV,RVESV,RVSV reduced more significantly than that of after three days(P＜0.05),but RVEF did not decrease significantly(P＞0.05).Conclusion The preload of right heart was reduced after transcatheter closure of ASD. The diameter of right ventricle,right atrium and pulmonary artery gradually decreased, and the pulmonary artery systolic pressure decreased.However,the systole peak strain(ε)and strain rate(SR)on the middle and basal segments in right free wall and interventricular septal before and after transcatheter closure of ASD did not change.It indicates that the increased regional myocardial contractility of right ventricular did not change after ASD closure.