All patients that are willing to participate will undergo stress testing (i.e. volume challenge and low dose dobutamine stress) to determine whether patients display severe dynamic FMR under stress conditions. Within the registry patients will be followed-up during routine ambulatory visits for three years. Patients with severe dynamic functional mitral regurgitation will be compared to patients without severe dynamic FMR. Record of clinical events during the FUP will be performed. Routine laboratory parameters, have been measured at inclusion. Additionally, neurohormone patterns will be measured at baseline and at peak stress.