"Echocardiographic evaluation of the functional mitral regurgitation after cardiac resynchronization therapy: which is the best approach?"

A strong association between functional mitral regurgitation severity and all-cause mortality and hospitalization was found in patients with dilated cardiomyopathy and left ventricular systolic dysfunction, with or without an implanted device. Many studies revealed a bidirectional link between the decrease in functional mitral regurgitation severity and the response to cardiac resynchronization therapy. This emphasizes the importance to find methods for mitral regurgitation evaluation in heart failure patients after device implantation. In this complex pathology, adequate measurement remains a challenge for clinicians. Echocardiography is the key technique used to confirm the diagnosis and to assess the severity and prognosis. In this review, we discuss the echocardiographic challenges in the evaluation of functional mitral regurgitation after cardiac resynchronization therapy. An integrated approach including various criteria is strongly recommended. The assessment includes the integration of data from 2D/3D echocardiography imaging, as well as Doppler measures of severity. For quantifying the regurgitation degree, the vena contracta width and the parameters derived from the PISA method, effective regurgitant orifice area and regurgitant volume, are the most useful. There is also important to provide information about the left ventricle and right ventricle dimensions and ejection fraction, as well as the left atrium, right atrium dimensions and the pulmonary arterial systolic pressure.