Cardiovascular magnetic resonance, mitral regurgitation and outcomes: the importance of accurate assessment in an era of increasing intervention

Assessing the severity of mitral regurgitation has been part of clinical practice since the advent of the stethoscope (presence of S3, soft S1, early A2, signs of pulmonary hypertension—loud P2 and parasternal heave, displaced apex beat, signs of left ventricular failure). Nowadays, imaging with echocardiography is the worldwide standard with its ability to give semi-quantitative and quantitative measures, including vena contracta length, effective regurgitant orifice area (EROA) and regurgitant volume (RVol) using the proximal isovelocity surface area (PISA) method, and measures of the haemodynamic consequences of mitral regurgitation (pulmonary vein systolic flow reversal, LV end-systolic diameter, left atrial area or volume, pulmonary systolic arterial pressure at rest).