The transition to decompensation in mitral regurg is dependent on the mechanisms of compensation and the severity of the valvular reguritant volume. What are two important determinants of outcome (with or without surgery)?
LV chamber size
What are the characteristics of compensated MR? (probably not a TQ he said)
• LVEDD<6 cm, LV LVESD<4 cm
What characterizes the transitional phase of MR?
•Worsening symptoms (usually)
• LVEF decreasing from normal or hyperdynamic to slightly depressed (ie, EF<55%)
What characterizes the decompensated phase of MR?
• LVEF<40%, LVEDD>7 cm, LVESD>4.5cm.
How are outcomes for the decompensated MR patient?
•Very important to recommend surgery prior to decompensation as surgical results are very poor in these patients.
What are the five parts of the mitral valve apparatus?
•2. Mitral Annulus
•3. Chordae Tendinae
•5. LV (papillary muscle, regional LV dysfunction at the origin of the muscle, etc)
What are the three things that can cause mitral regurg?
•1. Myxomatous degeneration of MV (MV Prolapse) (by far most common cause)
•2. Rheumatic changes (underdeveloped countries)
•3. SBE (subacute bacterial endocarditis)
If 3-12 of the chordae tendinae rupture, what happens? What causes this?
mild to severe mitral regurgitation, usually acute.
Fixation from RF
Disruption from SBE - Usually acute
What does progressive LA dilatation lead to?
Mitral valve being "pulled apart" d/t continuity of LA with leaflets
Ischemic heart disease can cause MR. How? IS it reversible?
•The papillary muscles contract late in the cardiac cycle, “end circulation” of the muscles can lead to MR by loss of “holding down” the leaflets due to ischemia of the papillary muscles. Chronic MR may develop, and it usually is reversible with revascularization techniques (PCI or CABG).
What are the signs and symptoms of MR?
•Dyspnea on Exertion (DOE)
•Palpitations- especially with atrial fibrillation
•CHF decompensation, orthopnea, PND, Functional Class III or IV
What are the key signs on PE of a patient with MR?
• LV heave
• Holosystolic Murmur, or Pan Systolic Murmur (PSM, HSM), at the apex, radiates in direction of MR jet, anterior or posterior (opposite leaflet).
•Decreased S1, wide split S2 from early A2, occasional S3
•Rapid rising and falling bounding pulse-volume problem like AR
If you feel a heave, what is the ejection fraction?
35% or lower.
What are the echocardiographic findings in MR?
•Chamber size (LA, LV) and function (EF increased at first)
•Doppler measurements of Flow, regurgitant volume (fraction), direction and volume of jet in LA, etc.
What is the medical tx for MR?
Decrease peripheral resistance to increase amount of blood exiting the aortic valve, thus decreasing backflow into the left atrium.
Vasodilators such as ARBs, ACEi, Hydralazine, nitrates.
What is LA resistance determined by?
LA size and compliance
What is the surgical procedure for the repair of MR?
•Mitral Valve Repair favored over Replacement
•Percutaneous Mitral “Clip”
What are the two basic mechanisms of acute mitral regurgitation?
•1. Ruptured mitral chordae tendinae due to myxomatous disease (was called MVP), infective endocarditis, trauma, rheumatic heart disease (either acute or chronic) or spontaneous rupture.
•2. Papillary muscle rupture due to acute MI or trauma or pap muscle displacement due to ischemia or MI.
What can lead to tissue valve leaflet rupture?
What can cause acute impaired closure of the mechanical valve?