Answer is C (Left Ventricular S3) The severity of Mitral Regurgitation may be judged clinically by the presence of left ventricular dilatation and the presence of third hea sound (Left Ventricular SJ? . These features indicate a more severe disease 'A third hea sound (S3) in chronic mitral regurgitation is usually indicative of severe regurgitation' Severity of Mitral Regurgitation: . If the murmur is harsher and has a lot of low and medium frequencies. It usually indicates a lot of flow and therefore will imply significant regurgitation. A harsh decrescendo mitral regurgitation murmur is usually indicative of severe regurgitation because the decrscendo effect is caused by early buildup of a very high v wave pressure in the left atrium resulting from a severe degree of regurgitation. Thus decreasing the gradient in late systole (If the murmur, on the other hand, is all pure high frequency and confined only to late systole. Then it must indicate a high pressure difference between the left ventricle and the left atrium and therefore only mild regurgitation). When the mitral regurgitation is severe, the volume overload on the left ventricle will be high, resulting in an enlarged left ventricle. This may be reflected in a displaced hyperdynamic wide -area left ventricular apical impulse. In addition, the hyperdynamic left ventricle will have rapid ejection. This will make the A2 occur early. Resulting in a wide-split S2. Thus, a wide -split S2 in the presence of mitral regurgitation is a sign of severe regurgitation if the wide split is not caused by P2 delay. In addition, severe regurgitation because of the volume load effect will have a torrential inflow through the mitral valve during diastole. This will set up the necessary conditions for the production of an S3 or a mid -diastolic inflow rumble. The presence of an S3 or an inflow rumble at the apex will, therefore, be a sign of significant mitral regurgitation as well. Severity of Mitral Regurgitation : Features indicating increased severity: Presence of Left ventricular S3 or an inflow rumble at the apex Harsh Decrescendo murmur with lot of low and medium frequencies Wide split S, due to early A2 (not caused by P2 delay) in presence of MR Note : Loudness and duration of Mitral regurgitation murmur does not always correlate with the severity of the regurgitation