Valvular heart disease - mitral regurgitation Flashcards
intro
incomplete closure of the mitral valve during systole
causes leakage of blood from the LV to the LA
aetiology (causes)
abnormalities of the valve leaflets, annulus, chordae tendinae, papillary muscles or LV
causes of PRIMARY mitral regurgitation (organic) - caused by the DIRECT INVOLVEMENT of the valve leaflets or chordae tendinae
- degenerative mitral valve disease (myxomatous, mitral valve prolapse, mitral annular calcification, ruptured chordae tendinae)
- rheumatic fever/heart disease
- infective endocarditis
- papillary muscle dysfunction/rupture - post MI
- ischaemic heart disease
causes of SECONDARY mitral regurgitation (functional) caused by the CHANGES OF THE LV that lead to valvular incompetence
- coronary artery disease
- prior MI causing papillary muscle involvement
- dilated and hypertrophic cardiomyopathy - LV dilation
- rheumatic AI diseases - SLE
- CT collagen disorders (EDS, Marfan’s)
- disorders caused by drugs eg. dopamine agonists (cabergoline) and centrally acting appetitie suppressants (fenfluramine)
pathophysiology
- reflux of blood into the LA causes LA dilation
- LA pressure increases with chronic regurgitation, but large LA accomodates a smaller increase in pressure
- whereas in acute regurgitation, there is normal compliance of LA so not much dilation - the LA pressure rises, sp the pulmonary venous pressure rises, leading to pulmonary oedema
- some SV is regurgitated, so SV increases to maintain forward CO and so the LV enlarges
an increased LV end-diastolic volume
causes an increased LA and pulmonary pressure
causes pulmonary venous congestion
causes pulmonary oedema
symptoms
- dysponea and orthopnoea - from pulmonary venous hypertension due to direct result of mitral regurgitation and secondarily as a consequence of LV failure
- fatigue and lethargy - due to reduced CO
- palpitations
- symptoms of causative disease eg. fever
- later stages - RHS HF and eventually congestive HF
- cardiac cachexia can develop
- thromboembolism in mitral regurgitation is less common than in mitral stenosis
- subacute infective endocarditis in mitral regurgitation is more common than in mitral stenosis
ACUTE MR = rapid pulmonary oedema, needs emergency valve repair as can be life threatening
CHRONIC MR = well tolerated but dilated LV causes HF and breathlessness
signs
- laterally displaced forceful diffuse apex beat - displaced hyperdynamic apex beat
- systolic thrill (if severe MR)
- soft S1 due to adjacent valve cusps partially closed by the time ventricular systole begins
- pansystolic murmur due to reflux of blood during systole, loudest at the apex, radiating widely over the precordium and into the left axilla
- mid-systolic click due to sudden prolapse of mitral valve and the tensing of chordae tendinae during systole (may be followed by a late systolic murmur for some reflux)
- prominent S3 due to sudden rush of blood back into the dilated LV in early diastole (may be followed by a short mid-diastolic flow murmur)
signs of AF and PULMONARY HYPERTENSION and HF develop later on, AF symptoms not as bad as in mitral stenosis
main signs being :
- holosystolic murmur heard best over the apex, radiating to the left axilla
- a displaced hyperdynamic apex beat
- signs of AF
diagnosis
ECHOS
TTE = shows LV function and MR severity
- dilated LA + LV
- chordae tendinae + papillary muscle rupture
- flow volume shown by colour Doppler for severity
TOE = assesses suitability for repair not replacement
- identifies structural valve abnormalities before surgery
- intraoperative helps see efficacy of valve repair
+ confirm diagnosis with cardiac catheter
investigations
CXR:
- LA + LV hypertrophy = chronic MR
- mitral valve calcification
- pulmonary oedema
- increased cardiothoracic ratio
ECG:
ACUTE MR = non-specific findings
- normal sinus rhythm
- AF
CHRONIC MR = cardiac remodelling
- LV hypertrophy : tall R waves in the LHS lateral leads (leads I, V6) and deep S waves in the RHS precordial leads (leads V1,V2)
- LA hypertrophy shows as LA delay if in sinus rhythm : bifid p waves (p mitrale)
cardiac catheter:
- confirms diagnosis
- excludes other valvular disease
- assesses CAD
- combines CABG with valve surgery
- for pt needing surigcal repair or replacement
management for mild/moderate MR
regular echos
+ prophylaxis against endocarditis
management for severe MR
SURGERY - repairs or replaces valve before LV is irreversible damaged
given to both:
- symptomatic pt with reduced LVEF <30%
- asymptomatic pt with LV dysfunction and reduced LVEF <60%
- asymptomatic pt with preserved LVEF + AF/pulmonary hypertension
if pt can’t have surgery or pt has residual symptoms after surgery
- give ACEi for HF
- control rate if AF
- anticoagulate if AF/embolism/prosthetic valve
- give diuretics to improve symptoms
- percutaneous mitral valve repair
mitral valve prolapse (Barlow’s syndrome/floppy mitral valve) is
myxomatous degeneration of mitral valve leaflets (becomes floppy)
peak incidence in
more commonly seen in young women
(more than in men or older women)
- familial incidence
seen commonly in pt w/
or associated w/
- CT disorders eg. Marfan’s, EDS, pseudoxanthoma elasticum
- cardiac issues eg. WPW syndrome, patent DA, ASD, cardiomyopathy
- congenital issues eg. Turner’s, OI
