Mitral Regurgitation (MR) is the backward flow of blood into the left atrium during ventricular systole causing an increased in LA pressure (can be acute or chronic).
ETIOLOGIES:
1. Mitral Annulus Pathology
- Mitral Annular Calcification (MAC)
- LV, LA dilation - increased pull on annulus with increasing dilation of chambers.
2. MV Leaflets Pathology
- Congenital
- Parachute MV
- MS disease processes
- Rheumatic (Calcific) stenosis
- Infective Endocarditis
- Perforations, vegetations
- Myxomatous degeneration
- Prolapse and flail
3. Chordae Pathology
- Myocardial Infarction
- Rupture of chordae, flail
- Infective Endocarditis
- Perforation or rupture of chordae, flail
- Myxomatous degeneration
- Elongation of chordate
4. Papillary Muscle Pathology
- Ischemia
- Pap. dysfunction
- Infarction
- Necrosis
- Post-infarction
- Rupture
5. LV Pathology
- Ischemic heart disease
- Cardiomyopathy (dilated)
Mitral Valve Prolapse
- Displacement of all or part of the MV leaflet(s) into the LA during ventricular systole.
- Posterior displacement beyond the MV annulus is also called Barlow's Syndrome, Systolic Click Murmur Syndrome, Floppy MV.
- M-mode and colour Coppler findings:
- Mid-late systolic sagging, >2 mm from C-D points
- Holosystolic sagging. >3mm from C-D points
- Eccentric MR jet (Coanda effect)
- Complications of MVP include flail leaflet or chordae in diastole.
Acute vs. Chronic Mitral Regurgitation
- Acute
- Ruptured papillary muscle or chordae leading to flail leaflet caused by myocardial infarction or endocarditis.
- Non-compliant LA leading to sudden increase in pressures
- Sudden pulmonary congestion and edema
- Increased stroke volume and cardiac output in initial stages
- Asymmetric CW spectral profile
- Chronic
- Causes: Calcific, Rheumatic, Myxomatous, Dilated or Ischemic Cardiomyopathy
- LA has increased compliance (enlargement) with small increase in pressure
- Minimal pulmonary congestion
- Increased stroke volume with decreased cardiac output
- Symmetric CW spectral profile
Findings of Aortic Regurgitation:
- Colour flow Doppler
- High velocity laminar jet at the vena contracta..
- Assess multiple views for spatial distribution, number of jets and direction.
- Spectral Analysis
- Use apical 5 or 3 chamber view with aligned parallel flow for PW Doppler.
- Peak E > 1.2m/s with normal deceleration time suggests severe MR. Dominant A wave suggests mild MR.
- Systolic flow reversal in the pulmonary veins, can diagnose severe MR
- Preserved S wave in pulmonary vein flow excludes severe MR.
