Mitral Regurgitation Flashcards
What is MR?
Leakage of blood backwards through the mitral valve each time LV contracts
What factors increase the annular dilatation and so volume regurgitated through the mitral valve?
Annulus enlargement:
Increase in preload, afterload and LV contractility
Annular enlargement -> regurgitant vol. increases
How does the LV compensate for mitral regurgitation?
Acute:
End-systolic pressure and volume DECREASE as blood is also pushed through MV to LA as well as aortic v.
Wall tension DECREASES
Chronic:
EDV increases (overload leads to LV to remodel as a thin-walled enlarged chamber)
ESV returns to normal
LVH
Explain reduced LA compliance to mitral regurgitation
Marked pressure rise
Thickening of atrial myocardium
Increase in PVR
Remodelling of pul. vasculature with PHT
What are the causes of mitral regurgitation?
Rheumatic fever Mitral valve prolapse Infective endocarditis Degenerative valve LV dilation and annular calcification
What are the signs in clinical examination?
Normal or reduced pulse JVP prominent if R HF Hyperdynamic apex beat RV heave Auscultation: reduced S1, split S2 Pansystolic murmur
What are the symptoms of acute mitral regurgitation?
Breathlessness due to:
Pulmonary oedema
Cardiogenic shock
What investigation should be carried out?
ECG
CXR
Angiography
Echo
What is the non-surgical treatment for acute MR?
Preload and afterload reduction:
Sodium nitropressuide
Dobutamine
LABP
What causes mitral valve prolapse?
Degeneration of the valve, occurs at about 50
There is genetic susceptibility
Explain increased LA compliance to mitral regurgitation
Marked volume enlargement
Lesser changes in pul. vasculature
Develops AF
How does mitral regurgitation cause atrial fibrillation?
The stretching and enlargement of left atrium causes the upper chambers of your heart beat chaotically and rapidly
What are the symptoms of chronic mitral regurgitation?
Fatigue
Exhaustion (low CO)
R HF
Dyspnoea or palpitation due to AF
What is cariogenic shock?
Condition where your heart suddenly can’t pump enough blood to meet your body’s needs
Why does the apex beat become hyperdynamic?
A valve leak will cause the ventricle to become dilated due to the extra volume of blood within it
