A Comparative Study Of Echocardiography And CT In The Evaluation Of Pulmonary Veins In Patients With Atrial Fibrillation

Part One:The comparison of single cardiac cycle real-time three-dimensional transesophageal echocardiography with computed tomography for assessment of the anatomical structure and inner diameter of pulmonary veinsObjective:To compare single cardiac cycle real-time three-dimensional transesophageal echocardiography(TEE)with computed tomography(CT)in evaluation of the anatomical structure and inner diameter of pulmonary veins.Methods:Among the 74 patients,the anatomy and inner diameter of pulmonary veins were assessed by both TEE and CT before the procedure of radiofrequency ablation.Results:By using the CT assessment as references,the detect rate of TEE were 99%and 97%for the right superior and inferior pulmonary veins,100%and 95%for the left superior and inferior veins.7(70%)cases of variant right middle and 2(67%)of left middle pulmonary vein were successfully identified by TEE.The inner diameters of pulmonary veins measured by TEE vs CT were right superior 19.10±4.13mm vs 20.59±4.75mm,right inferior 13.35±3.02mm vs 17.48±2.97mm,left superior 18.63±3.41mm vs 21.78 ± 3.77mm,and left inferior 12.47± 3.25mm vs 18.13 ± 3.31mm(P<0.001 for all),respectively.Conclusions:The single cardiac cycle real-time three-dimensional TEE had a high detectability of pulmonary veins,however underestimated the inner diameters of the veins compared with the CT reference.Therefore,TEE is not yet possible to replace CT as an independent method to evaluate pulmonary veins for clinical practice.Part Two:Reproducibility of pulmonary vein diameter by transthoracic echocardiographyObjective:Transthoracic echocardiography can be used to evaluate the diameter and anatomy of pulmonary veins in clinical practice.The purpose of this study was to assess the intra-and inter-readers reproducibility of the pulmonary veins measured by transthoracic echocardiography by the standardized examination and measurement process.Methods:A total of 20 patients without pulmonary venous anomalies or unilateral pulmonary venous malformations were recruited.The transthoracicly echocardiographic image of the pulmonary veins were obtained according to the standardized protocol and stored for the off-line analyes.Reader A accessed the the anatomy and diameter of the pulmonary veins twice in one week and in three months,respectively.The reader B analyzed the stored images once by using the same protocol.Thereafter,the intra-and inter-reader reproducibility of the mearuments were statistically assessed by using the Bland-Altman method.Results:Of 20 patients with an age of 56.7±14.0 years,12(60%)were women.The overall averages of the pulmonary vein diameter measured by reader A and reader B were 17.61±1.54mm for right upper,16.17± 1.72 mm for right inferior,17.7± 1.53 mm for left upper and 16.10±1.65 mm for left inferior viens.The intra-reader differences(reader A)of the pulmonary vein diameter were-0.35±0.88 mm for right upper,0.30±1.26 mm for right inferior,0.15± 1.31 mm for left upper and 0.10±0.79 mm left inferior veins,while the corresponding inter-reader differences(between Readers A and B)were-0.08±2.17 mm,-0.45± 1.89 mm,-0.23±2.60 mm and 0.55±2.04 mm,respecitively.Paired t-test comparsions showed that there was no significant difference of the measurement within the reader(P?0.24)and between the two readers(P?0.090).The intra and inter-reader reproducibitliy were 1.75-2.62 and 3.8-5.2,respectively,and accounted for 10?16%and 23-29%of the overall averages of the measurement.Conclusions:Transthoracic echocardiography produces repeatable measrues of pulmonary vein diameter,and proved the feasiblity and retionale of the following comparison study between transthoracic echocardiography and comupted tomography.Part Three:Comparison of transthoracic echocardiography with computed tomography in evaluation of pulmonary veinsObjective:Transesophageal echocardiography can be used to assessing pulmonary veins for atrial fibrillation ablation.No study focused on the role of transthoracic echocardiography in evaluating diameter and anatomy of pulmonary veins.Methods:For 142 atrial fibrillation patient(57.7%men;mean age,60.5)hospitalised for catheter ablation,we assessed and compared pulmonary veins by transthoracic echocardiography with cardiac CT before ablation.Among them,17 patients had a follow-up study.Results:Transthoracic echocardiography(TTE)identified and determined the diameter for 140(98.6%)of both right and life/left superior PVs,136(95.7%)right and 135(95.1%)left inferior PVs.The separate middle PV ostia were identified in 14 out of the 22 patients(63.6%)for right side and 2 out of 4(50.0%)for left side.The PV diameters before ablation assessed by CT vs.TTE were 18.03 vs.18.07 mm for right superior,15.94 vs.15.51 mm for right inferior,18.57 vs.18.42 mm for left superior,and 15.64 vs.15.45 mm for left inferior.The paired differences between the assessments of CT and TTE were not significant(P?0.31)except for right inferior vein with a CT minus TTE difference of-0.41 mm(P=0.018).The follow-up PV diameters by both CT(P?0.069)and TTE(P?0.093)were not different from baseline measurement.Conclusions:With better understanding PV anatomy in TTE images,the diameter assessment of PV by non-invasive TTE is feasible.However,the clear identification of anatomic variation might still be challenging.