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.
Exercise-Induced Left Bundle Branch Block Resulting in Severe Mitral Regurgitation
