Valvular heart disease, endocarditis Flashcards
Valve components
- valve ring
- cusp
- chordae
- papillary muscles
functional failure in valves
mitral stenosis
mitral incompetence
aortic stenosis
aortic incompetence
Stenosis
Narrowing of the valve outlet caused by thickening of valve cusps, or increased rigidity or scarring.
Incompetence
Or insufficiency or regurgitation (which is what happens) caused by incomplete seal when valves close, allowing blood to flow backwards
First: heart sound
mitral and tricuspid - systole
Second: heart sound
aorta and pulmonary – diastole
Congenital heart disease
bicuspid valve, atresia
• Cardiomyopathy
hypertrophic, dilated
Acquired
– Rheumatic fever
– Myocardial infarction
– Age related – idiopathic aortic calcific stenosis – Endocarditis
aortic stenosis causes
calcification of congenital bicuspid valve senile calcific degeneration
rheumatic fever
consequences of aortic stenosis
- increases the work of the heart
- ventricular hypertrophy
- causes cardiac failure late in the clinical course
- clinical symptoms include:
dyspnoea
angina
syncope
causes of aortic incompentance
infective endocarditis
rheumatic fever
marfans syndrome
aortic regurgitation
- increases the volume of blood to be pumped significantly
- increases the work of the heart
cardiac hypertrophy - cardiac failure
- occur in the presence of aortic stenosis
cusp damage
– Rheumatic heart disease – scarring, contraction
– Floppy valve & Marfan syndrome - stretch
– Infective endocarditis - perforation
causes of mitral incompetence
- cusp damage
- chordae
- papillary muscle
- valve ring
mitral stenosis
congenital post rheumatic fever restricts blood flow to left ventricle atrial fibrillation back pressure results in pulmonary hypertension finally causes heart failure
Define infective endocarditis
• Infection of valve with formation of
thrombotic vegetations
• Virulence of organisms determines damage and severity of the clinical illness
Risk factors for infective endocarditis
- valve damage
- bacteraemia
- immunosuppression
Rheumatic fever
• Acute multisystem disease
–heart (myocarditis, valvulitis, pericarditis), joints, connective tissue
• 3 weeks post Streptococcal infection(usually pharyngitis)
• Immune mediated rather than direct infection
• Occurs in children:4-16years
• May occur in recurrent episodes
• Chronic valve disease decades later
Acute Native Valve Endocarditis
– valves may be normal
– aggressive disease
– virulent organisms, such as Staph. aureus and group B streptococci
• Subacute Native Valve Endocarditis
– abnormal valves
– indolent but may deteriorate
– alpha-haemolytic streptococci, enterococci
• Prosthetic valve endocarditis
– 10-20% of cases
– 5% of mechanical and bio-prosthetic valves become infected
– mitral are more susceptible than aortic
IV Drug abuse
– 75% have no underlying valvular abnormalities
– 50% involve the tricuspid valve
– Staph. aureus most common
For more reading see
http://emedicine.medscape.com/article/216650-overview#a2
Principles of diagnosis, treatment and prevention of infective endocarditis
• Treat Strep. infection with antibiotics • Prophylactic cover for invasive procedures eg dental work • Replacedamagedvalves • Clinical suspicion & signs • Imaging – especially echocardiography • Blood culture • Intravenous antibiotics
Local and systemic complications of infective endocarditis
clubbing of fingers
prominent splinter heamoraghes
composition and causes of vegetations
Group D Streptococcus, gut commensals, skin Strep
(Coxiella, fungi, Candida)
fibrin and platelets and bacteria
