Mechanism of Ischemic Mitral Regurgitation

Augmented leaflet tethering due to the outward displacement of the PMs with LV remodeling appears to be a basic mechanism for ischemic MR. Further, annular dilatation and LV dysfunction likely contribute to the development of MR in the presence of augmented tethering. PM dysfunction per se does not usually cause ischemic MR and may occasionally attenuate tethering and MR. The concept of PM dyssynchrony is important and further study to separate effects of PM dyssynchrony from other factors are required. Although surgical annuloplasty is often effective in reversing ischemic MR, the frequency of patients with persistent or recurrent ischemic MR after surgical ring annuloplasty even with advanced down sizing suggests the need for approaches to address tethering. Finally, leaflet tethering in patients with ischemic MR can vary within a single patient and between patients, indicating the multiple and individualized approaches may be required to correct ischemic MR in affected patients.