Cardiac Resynchronization Therapy for Functional Ischaemic Mitral Regurgitation

Abstract

Functional mitral regurgitation (MR) is a common finding in patients with heart failure (HF). It results from an imbalance between closing and tethering forces that ensure valve competence as a consequence of systolic dysfunction and altered geometry of the left ventricle (LV). In some patients, mechanical asynchrony in chamber contraction might be present and also contributes to the development of MR, either leading to diastolic MR, systolic MR or both.

Cardiac resynchronization therapy (CRT) has the potential to reverse the vicious cycle resulting in MR worsening, specifically in those patients with abnormal electrical conduction leading to disturbances in mechanical contraction. CRT leads to LV reverse remodeling and reduces morbidity and mortality, in addition to symptoms and exercise capacity improvement. CRT can effectively reduce functional MR by improving mechanical dyssynchrony in cardiac contraction, which leads to improve LV systolic and diastolic function, and also by inducing reverse LV remodeling which in turn restores the abnormal geometry of the mitral valve apparatus. There is growing evidence that CRT can be considered as a first line treatment in patients with HF and severe secondary MR who have mechanical dyssynchrony amenable to be electrically corrected with CRT.