Assessment Of Left Atrial Appendage Shape,Mechanical Function And Peak Empty Velocity In Patients With Atrial Fibrillation By Real-time Three-dimensional Transesophageal Echocardiography

BackgroundAtrial fibrillation(AF)is one of the most common arrhythmia,male morbidity slightly higher than women,and the incidence increased with age.Atrial fibrillation for 48 hours to form the left atrial appendage thrombus,and left atrial appendage is the most common site of thrombosis.90% of patients with nonvalvular atrial fibrillation and 57% of patients with valvular atrial fibrillation with thrombosis are located in the left atrial appendage.Therefore,accurate assessment of the left atrial appendage shape,mechanical function and peak empty velocity of patients with atrial fibrillation plays a very important role in treatment and timing of surgery and prognosis evaluation.Three-dimensional transesophageal echocardiography after static,dynamic,real-time three stages of development.At present,real time three-dimensional transesophageal echocardiography can clearly show the dynamic three-dimensional anatomical structure of the left atrial appendage,more accurately provide the functional parameters of the left atrial appendage.At the same time,real time three-dimensional transesophageal echocardiography can provide reliable information for the clinical evaluation of the shape,mechanical function and peak empty velocity of the left atrial appendage.ObjectiveTo evaluate the mechanical function,the peak empty velocity(PEV)of the left atrial appendage(LAA)and the correlation between them in patients with atrial fibrillation by real time three-dimensional transesophageal echocardiography(RT-3D TEE).MethodsFifty-one patients with atrial fibrillation and thirty-eight patients with sinus rhythm underwent RT-3D TEE.LAA ejection fraction(EF)was measured by twodimensional area(EFA-2D),three-dimensional area(EFA-3D)and three-dimensional volume(EFV-3D)respectively,PEV of LAA was measured by Pulse Doppler Wave(PW).In the range of 0 ° ~ 180 ° show two-dimensional structure of the left atrial appendage.At 45 °,the long axis of left atrial appendage,store two-dimensional images of the left atrial appendage.Click on XPlane,through two mutually perpendicular two-dimensional images to ensure that the left atrial appendage is completed,then start 3D ZOOM mode to collect the left atrial appendage three-dimensional images.The peak empty velocity of the left atrial appendage was measured by pulse Doppler at 1 cm from the left atrial appendage orifice.Check the process of connecting with ECG and image synchronization display.Continuous record 5 cardiac cycle images in AF patients and 3 cardiac cycle images in SR patients,the image is stored to the hard disk for off-line analysis,complete image acquisition.The three-dimensional images of the left atrial appendage were randomly cut to show the number of lobes;the two-dimensional area method,the three-dimensional area method and the three-dimensional volume method were used to measure the ejection fraction of the left atrial appendage,to compare whether it has statistical significance by one-way ANOVA.Atrial fibrillation group and sinus rhythm group the ejection fraction and peak empty velocity of the left atrial appendage compared by using independent sample t test.The peak empty velocity of left atrial appendage was measured by pulsed wave Doppler and Pearson correlation was used to analyze the correlation between left atrial appendage ejection fraction and peak empty velocity.The variability of inter-observer and intra-observer was analyzed using Bland–Altman consistency analysis.The difference had statistical significance(P<0.05).ResultsIn 89 patients,the most frequent number of LAA lobes was 2(n=48),followed by 3(n =24),1(n =9),and 4(n =8).ANOVA analysis compared each different TEE methods,all P values >0.05,there is no significant difference between them.The EF and PEV of LAA in AF group were lower than SR group,the differences were statistically significant(FEFA-2D=4.374,P=0.000;FEFA-3D=6.440,P=0.001;FEFV-3D=52.469,P=0.004;FPEV=1.640,P=0.004).The EF and PEV of LAA had a positive correlation(rEFA-2D=0.504,P=0.000;rEFA-3D=0.644,P=0.000;rEFV-3D=0.644,P=0.000).Bland-Altman analysis about observer variability’s are presented in 43 patients.There are lower variability in observer variability of LAA ejection fraction and peak empty velocity.ConclusionsRT-3D TEE can evaluates the mechanical function and PEV of LAA in patients with AF.1.The left atrial appendage has different shapes between different individuals,real-time three-dimensional transesophageal echocardiography can clearly show the number of the left atrial appendage lobes,measuring the orifice diameter and depth;2.Real-time three-dimensional transesophageal echocardiography can quantitatively evaluate the left atrial appendage mechanical function and peak empty velocity;3.The mechanical function,ejection fraction and peak empty velocity of left atrial appendage in patients with atrial fibrillation than sinus rhythm patients decreased;4.The peak empty velocity of the left atrial appendage can indirectly reflect its contraction function.