The disproportionate/proportionate nature of secondary mitral regurgitation (sMR) has been recently introduced to explain the different outcomes of patients undergoing percutaneous mitral valve procedures [1,2]. The proportionality is determined by the ratio between mitral effective regurgitant orifice area (EROA) or regurgitant volume (RV) and left ventricular (LV) volume. By the proposed framework, in patients with similar ejection fraction (EF) and similar EROA or RV, disproportionate MR is characterized by small LV end-diastolic-volume, low LV stroke volume (SV) and, therefore, by an out of proportion regurgitant fraction (RF) for the same value of EROA [3].
