Collateral-dependent ischemic mitral regurgitation.

There is much debate on the pathogenesis of ischemic mitral regurgitation (MR), usually related to global or regional left ventricular dysfunction or remodeling secondary to chronic ischemic changes, altering the tethering and closing forces on the mitral apparatus. There is a paucity of literature describing MR in the setting of acute ischemia. We describe a case in which the MR was dynamic and directly related to changes in coronary collateral flow.