Objectives:To evaluate the valvular and cardiac function,cardiac reverse remodeling at 6-month after transcatheter edge-to-edge repair(TEER)for patients with functional and degenerative mitral valve regurgitation,and summarize the experience of echocardiography application. Methods:The clinical data of 93 patients with moderate to severe mitral regurgitation(MR)treated with TEER and completed 6-month follow-up in Yunnan Fuwai Cardiovascular Hospital from July 2022 to February 2023 were retrospectively analyzed.Patients were divided into functional mitral regurgitation(FMR)and degenerative mitral regurgitation(DMR)groups according to MR etiology.The valve characteristic parameters,as well as valvular function,chamber volume and cardiac functional parameters before and at 6 months after operation were compared.The key points of echocardiography application were summarized. Results:Among all patients,71 were FMR and 22 were DMR.There were differences in valve structure between the two groups.Mitral TEER were successfully accomplished and all patients completed 6-month follow-up.The key points of echocardiography application included:valve structure analysis,atrial septal puncture location,device delivery process monitoring and image optimization during clamping process.The mitral regurgitation grade and NYHA grade were significantly improved in all patients at 6 months after TEER(P<0.05),and the mean mitral valve pressure gradient was higher than that before operation(P<0.05).Left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV)and left atrial volume index in FMR group were significantly decreased(P<0.05),while left ventricular and left atrial volume in DMR group remained unchanged(P>0.05).There were no significant changes in left ventricular ejection fraction and left ventricular global strain in both groups during the observation period(P>0.05).The changes of LVEDV and LVESV before and after operation were more significant in FMR group than those in DMR group(P<0.05). Conclusions:Mitral TEER can reduce the degree of regurgitation and improve cardiac function in the early postoperative period for moderate and severe MR patients with different etiologies.There are differences in preoperative valve structure and postoperative cardiac reverse remodeling between FMR and DMR patients.Echocardiography is an important imaging technique for the evaluation and monitoring process before,during and post mitral TEER.