Chronic heart failure (HF) is frequently accompanied by functional mitral regurgitation (FMR) caused by left ventricular (LV) remodeling and subsequent papillary muscle displacement resulting in mitral valve (MV) leaflet tethering, dilatation and flattening of the mitral annulus and reduced closing forces. Up to moderate FMR affects the majority of patients with systolic heart failure - roughly 80% - still independently increasing mortality. Every fifth patient with chronic heart failure experiences a progression of FMR during the first three years of follow up despite guideline directed heart failure therapy, which is independently associated with a poor prognosis. Furthermore, MR is well known to have a strong dynamic component not only during the cardiac cycle at rest and with exercise.