What is the most important diagnostic feature of mitral regurgitation?

What is the most important diagnostic feature of mitral regurgitation?

1. Apical location of the murmur is the most important diagnostic feature of mitral regurgitation.
2. Second is the blowing quality in chronic mitral regurgitation.
3. Third is the timing – chronic rheumatic MR is pan systolic while that in mitral valve prolapse can be mid or late systolic.

Conduction pattern of the murmur is variable depending on the etiology. Classical rheumatic MR is conducted to the axilla and back, while that of papillary muscle dysfunction is conducted medially to the base of the heart.

Mitral regurgitation is the most common valvular abnormality with about 2% prevalence in the general population. Prevalence increases as age advances, due to degenerative changes in the mitral valve [1]. Mitral regurgitation secondary to left ventricular dilatation causing failure of co-optation of the mitral leaflets is known as functional mitral regurgitation. In many such cases the MR murmur may not be audible because of reduced force of contraction of the left ventricle. MR can be detected on colour Doppler Echocardiogram in those cases.

Diastolic mitral regurgitation due to left ventricular dilatation usually is not associated with a murmur. But one of the mechanisms for the Austin Flint murmur in chronic severe aortic regurgitation is said to be diastolic mitral regurgitation.

Reference

1. Steven Douedi,  Hani Douedi. Mitral Regurgitation. Treasure Island (FL): StatPearls Publishing; 2020 Jan. StatPearls [Internet].