Cardiac Resynchronisation Therapy or MitraClip® Implantation for Patients with Severe Mitral Regurgitation and Left Bundle Branch Block?

Secondary or functional mitral regurgitation (FMR) is a common problem in patients with chronic heart failure (HF). About one-third of patients with chronic HF also have left bundle branch block (LBBB). Approximately one-third of patients with an indication for cardiac resynchronisation therapy (CRT) have moderate-to-severe FMR. This FMR may either be a consequence of systolic dysfunction or it may occur due to dyssynchrony. Both directly reducing FMR and correcting cardiac dyssynchrony are viable therapeutic approaches in selected patients, according to the 2012 European Society of Cardiology (ESC) Guidelines for valvular heart disease. Initial presence of FMR is an independent predictor of lack of clinical response to CRT. Patients undergoing CRT without signs of significant clinical improvement may be considered candidates for the percutaneous MitraClip® procedure. As yet, there are not enough data to select patients that would benefit from being treated primarily with MitraClip. A clinical trial in HF patients to be randomised to either MitraClip procedure or CRT is needed to confirm actual ESC Guideline therapy.