| Objectives: In this study,three-dimensional transesophageal echocardiography was used to evaluate the differences of mitral valve structure and motion changes in patients with persistent atrial fibrillation(Ps AF)before and after radiofrequency ablation,and to further explore the mechanism of the effect of radiofrequency ablation on mitral regurgitation.Methods: This study prospectively included patients who received radiofrequency ablation for persistent atrial fibrillation in the Department of Cardiology of Dalian Central Hospital from January 2022 to January 2023 and completed follow-up.Hospital Exclusion criteria: primary valvular disease,invasive,restrictive or hypertrophic cardiomyopathy,congenital heart disease,previous cardiac valve surgery,left ventricular wall segmental motion abnormality,intracardiac thrombus,failure of radiofrequency ablation,poor imaging quality of three-dimensional transesophageal echocardiography,and lost patients.A total of 44 patients were included in the study and were divided into two groups according to the degree of regurgitation of the effective regurgitant orifice area(EROA): EROA<0.20 cm ~2 Group and EROA ≥0.20 cm ~2 Group.All patients were evaluated by two-dimensional transthoracic echocardiography and three-dimensional transesophageal echocardiography before and3 months after radiofrequency ablation.The general baseline data of patients were collected,including age,gender,height,weight,body mass index(BMI),history of hypertension,history of diabetes,history of coronary heart disease,etc.The left ventricular end-diastolic diameter(LVD),left atrial diameter(LAD),left ventricular ejection fraction(LVEF),early diastolic peak velocity(E)of the mitral valve orifice,the maximum velocityat the ventricular septum of the mitral annulus during diastolic period(interval e ’),the maximum motion velocity at the lateral wall of the left ventricle of the mitral annulus(lateral septal e ’),the average value of the two and the average E/e’ value,the left atrial volume(LAV)and the left atrium global longitudinal strain(LAGLS)were measured by two-dimensional transthoracic echocardiography.Three-dimensional transesophageal echocardiography was used to evaluate mitral valve structure and motion changes.Determine a series of mitral annulus parameters including the anteroposterior diameter of mitral annulus,the perimeter of mitral annulus,the height of mitral annulus,the mitral annulus area,the leaflet area of mitral valve,and the non-planar angle,and compare and analyze the changes of the mitral annulus area with the cardiac cycle,including isovolumic systole(immediately after the mitral valve begins to close),rapid ejection(the largest early opening of aortic valve),isovolumic diastole(immediately after the aortic valve closes),rapid filling(the largest early opening of mitral valve),and atrial systole(before the mitral valve closes).SPSS 26.0software was used for statistical analysis,and mixed design analysis of variance was used to compare the statistical differences of various parameters between the patients before and 3 months after operation.Single factor and multiple factor linear regression analysis was used to predict and analyze the factors affecting the improvement of the severity of functional mitral regurgitation,and to determine the independent predictive factors affecting the improvement of the severity of functional mitral regurgitation.P<0.05 is statistically significant.Results: Before radiofrequency ablation,at EROA ≥ 0.20 cm ~2 Group and EROA <0.20cm~2 in the group comparison,the E was higher(82.60±25.31cm/s 比 100.79±20.53cm/s,P=0.046),the height of mitral annulus was lower(0.75±0.20 cm vs 0.59±0.16 cm,P=0.013),and the change rate of presystolic mitral valve area was lower(5.94±0.50%比 5.04±0.59%,P<0.001).Three months after radiofrequency ablation,the structure and function of mitral annulus changed.Compared with that before operation,three months after operation,LAD decreased(45.73±5.49 mm 比 44.68±5.50 mm,P=0.016),LAV decreased(92.45±21.25 ml 比 84.77±21.20 ml,P<0.001),LAGLS increased(9.95±5.50%比 11.48±6.07%,P=0.003),LVEF increased(58.25±6.82%比59.75±6.19%,P=0.018),EROA decreased(0.16±0.07cm~2比 0.09±0.06cm~2,P<0.001),the anteroposterior diameter of mitral annulus decreased(3.07±0.46 cm 比 2.97±0.34 cm,P=0.002),the perimeter of mitral annulus decreased(11.82±1.41 cm 比 11.46±1.06 cm,P=0.006),and the mitral annulus area decreased(10.12±1.94cm~2比 8.78±1.64cm~2,P<0.001),the leaflet area of mitral valve decreased(11.47±2.82cm~2比 10.84±2.09cm~2,P=0.017),the non-planar angle became smaller(125.94±15.20°比 122.13±16.33°,P=0.045),the change rate of total mitral valve area became higher(10.63±0.81%比 18.63±0.80%,P<0.001),and the change rate of presystolic mitral valve area became higher(5.55±0.70%比 10.17±0.67%,P<0.001).Multivariate linear regression analysis showed that the change rate of presystolic mitral valve area was an independent predictor of the improvement of the severity of mitral regurgitation(P<0.001).At EROA≥0.20cm~2 Group and EROA<0.20cm~2 in the group comparison,3 months after radiofrequency ablation,the improvement of EROA was more obvious(0.05±0.04cm~2比 0.11±0.04cm~2,P<0.001),and the change rate of presystolic mitral valve area was also more significant(5.28±0.92%比 6.07±0.52%,P=0.001).Conclusion:The mitral annular motion function in patients with persistent atrial fibrillation is impaired,which is mainly manifested by the reduction of annular motion in the early stage of contraction.The more obvious the reduction of annular motion in pre-striction,the more severe the degree of functional mitral regurgitation.The change rate of presystolic mitral valve area is an independent factor affecting the severity of functional mitral regurgitation.Radiofrequency ablation can gradually restore the structure and motor function of mitral annulus by restoring sinus rhythm,thus improving functional mitral regurgitation in patients with persistent atrial fibrillation. |
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