Evaluation of Right Ventricular Global Longitudinal Function in Patients with Tetralogy of Fallot by Two-dimensional Ultrasound Speckle Tracking Imaging

Quantification of right ventricular(RV)volume and function remains a challenge because of RV complex geometry by conventional echocardiography.The purpose of this study was to assess RV global longitudinal function in patients with tetralogy of Fallot(TOF)by 2-dimensional ultrasound speckle tracking imaging(STI).Thirty-eight patients with TOF were enrolled in this study and divided into child group(n=25)and adult group(n=13)according to age.Thirty-eight age-and sex-matched normal subjects were selected as control groups including child control group(n=25)and adult control group(n=13).RV global longitudinal peak systolic strain(GLS),strain rate(GLSRs),early diastolic strain rate(GLSRe)and late diastolic strain rate(GLSRa)were measured in all subjects by STI from the apical 4-chamber view and compared between groups.Furthermore,the main factors affecting the RV global longitudinal functional parameters were assessed.Compared with those in controls,RV GLS,GLSRs and GLSRe were significantly reduced in patients with TOF(P<0.05 for all).RV GLSRs was significantly decreased in adult patients with TOF as compared with that in child patients(P<0.05).There was no significant difference in RV GLS,GLSRe and GLSRa between child and adult TOF groups(P>0.05).The diameter of right ventricle,main pulmonary artery and ventricular septum defect had correlations with RV GLSRs(r1=-0.490,r2=0.580,r3=-0.528,respectively,P<0.05 for all).Tricuspid annular plane peak systolic velocity(Sm)was the independent predictor of RV global strain and strain rate(β1=0.355,P1=0.031,β2=0.307,P2=0.021).RV global longitudinal function is decreased in patients with TOF,especially in adult patients.STI is a sensitive and accurate technique in RV global functional assessment.