Functional Mitral Regurgitation (MR), due to incomplete mitral leaflet closure rather than an inherent
abnormality in the valve apparatus, is a highly prevalent condition that is associated with an adverse prognosis in
patients with heart failure. To date, traditional medical therapies have largely been ineffective, and enthusiasm for
various surgical strategies has been limited by their lack of prognostic benefit and perceived high risk. In order to
overcome some of these issues, a number of percutaneous approaches have recently emerged, and while these
techniques are still in the research arena, there is already encouraging early data. This chapter will address the
pathophysiologal mechanisms involved in functional MR, and summarise the current data available on percutaneous
mitral valve therapies, with a particular emphasis on devices involving ‘indirect annuloplasty’ via the coronary sinus.
