Evaluation Of Left Atrial Function By Real Time Three-dimensional Echocardiography And Two-dimensional Speckle Tracking Imaging In Heart Transplant Recipients

Part1 Real-time Three-Dimensional Echocardiographic Quantification of Left Atrial Volume in Heart Transplant RecipientsObjective: The purpose of this study was to testify the feasibility and accuracy of realtime three-dimensional echocardiography(RT-3DE)and two-dimensional echocardiography(2DE)to evaluate the left atrial(LA)volume against cardiac magnetic resonance(CMR)in heart transplant(HT)recipients.Methods: Thirty-one HT recipients(23 male;mean age 46 ± 14 years;median time from transplantation 1.2 years)who received both echocardiography and CMR examination on the same day were prospectively enrolled.Standard biatrial technique was employed in 12 subjects whereas 19 underwent bicaval techniques.2DE and RT-3DE derived values of the LA volume were compared with the corresponding CMR reference values using linear regression with Pearson correlation coefficients and Bland-Altman analyses to assess the bias and limits of agreement(LOA).Paired sample t test was used to estimate LA volume differences for respective inter-technique values.Differences in LA volume between biatrial technique and bicaval technique were assessed using two-sample t test.Reproducibility of 2DE and RT-3DE techniques was assessed by intraclass correlation coefficient.Results:(1)RT-3DE derived LA volume values showed higher correlation with CMR than 2DE measurements in HT recipients(r = 0.93 vs.r = 0.76 for maximal LA volume;r = 0.91 vs.r = 0.81 for minimal LA volume).(2)LA volume quantification as determined with 2DE revealed a maximal LA volume of 79 ± 22 ml and a minimal LA volume of 49 ± 18 ml,whereas MRI showed a maximal LA volume of 89 ± 23 ml and a minimal LA volume of 76 ± 22 ml(P = 0.001 for maximal LA volume and P < 0.001 for minimal LA volume).Bland-Altman analysis revealed biases of-10 ml and-26 ml,LOA of(-41,21)ml and(-51,-1)ml,respectively.(3)There was significant difference between RT-3DE and CMR in minimal LA volume(RT-3DE: 61 ± 17 ml;CMR: 76 ± 22 ml,P < 0.001),with a bias of-15 ml and LOA of(-34,4)ml.However,no significant difference between RT-3DE and CMR was observed in maximal LA volume(RT-3DE: 86 ± 22 ml;CMR: 89 ± 23 ml,P = 0.079),with a bias of-3 ml and LOA of(-19,14)ml.(4)Individuals operated with the biatrial technique presented higher LA volume with subjects with bicaval technique(P < 0.05).(5)Inter-observer and intra-observer agreement were excellent for 2DE and RT-3DE parameters.Conclusions: RT-3DE derived LA volume measurements are more accurate than 2DE based analysis in HT recipients.RT-3DE may be a valid alternative to CMR for quantification LA volume in HT recipients.Part2 Evaluation of Left Atrial Function by Two-dimensional Speckle Tracking Imaging and Real Time Three-dimensional Echocardiography in Heart Transplant RecipientsBackground: The aims of this study were to explore left atrial(LA)function by using real time three-dimensional echocardiography(RT-3DE)and two-dimensional speckle tracking imaging(2D-STI)in clinically stable patients after heart transplant(HT).Methods: This study enrolled 112 clinically well HT patients(84 male;mean age 47 ± 12 years)and 40 healthy controls(32 male;mean age 43 ± 10 years).The 2D images of the apical four-and two-chamber views and 3D full volume images of LA were acquired,and analyzed using the software of 2D Cardiac Performance Analysis and Tom Tec 4D LV-Analysis offline.Peak LA strain,passive LA strain,passive LA strain rate,active LA strain and active LA strain rate were acquired from 2D-STI,left atrial emptying fraction(LAEF)was acquired from RT-3DE.LA reservoir function was assessed by using the peak LA strain and LAEF.LA conduit function was assessed by using passive LA strain,passive LA strain rate.LA pump function was assessed by using active LA strain and active LA strain rate.Differences in LA function between HT patients and healthy controls were assessed using two-sample t-test.Univariate linear regression analysis and multivariable linear regression models were used to analyze the correlates of reduced peak LA strain in HT patients.Results:(1)There were no differences between the HT group and the healthy controls in sex,age,body surface area,body mass index.However,the subjects underwent HT were faster heart rate than healthy controls(P < 0.05).(2)Compared with controls,HT patients had larger LA volume,smaller left ventricular(LV)volume and higher LV mass index compared with controls(all P < 0.05).Moreover,the measurements of LV ejection fraction and LV global longitudinal strain(GLS)were decreased in HT group(both P < 0.05).(3)Compared with controls,HT patients had worse LA reservoir(peak LA strain: 18.1 ± 5.6% vs 44.2 ± 6.5%;LAEF:32.0 ± 10.2% vs 60.3 ± 7.3%;both P < 0.001),conduit(passive LA strain: 14.1 ± 4.8% vs 26.7 ± 6.4%,passive LA strain rate:-1.17 ± 0.47s-1 vs-2.03 ± 0.47s-1;both P < 0.001),and pump function(active LA strain: 4.4 ± 2.3% vs 17.5 ± 4.7%;active LA strain rate:-1.77 ± 0.51s-1 vs-0.62 ± 0.29s-1;both P < 0.001)(4)Surgery of HT,age,LV GLS,LV end-diastolic volume index,e′,LA volume were independent correlates of reduced LAS-peak in HT patients.(5)Inter-observer and intra-observer agreement were excellent for LAS-peak and LV GLS.Conclusions: In HT cohort,we observed impairment in all phases of LA function.RT-3DE and 2D-STI play important roles in the evaluation of LA function in HT recipients.