Valvular disease Flashcards
What percentage of heart failure involves valve disease?
10%
What are the components of the heart valves?
- Valve rings
- Cusp
- Chordae
- Papillary muscle (mitral and tricuspid only)
(pathologies can be due to problems in any of these structures)
What is the function of the valve cusps?
To allow forward flow but to prevent back-flow
What is the definition of stenosis?
Narrowing of the valve outlet caused by thickening of valve cusps, or increased rigidity or scarring
What is the definition of incompetence?
(aka insufficiency or regurgitation)
- Caused by incomplete seal when valves close, allowing blood to flow backwards
What are the aquired causes of cardiac valve stenosis?
- Rheumatic fever
- MI
- Age related - idiopathic aortic calcific stenosis
- Endocarditis
What valves can be heard in systole?
Mitral and Tricuspid
What valves can be heard in diastole?
Aortic and pulmonary
Common causes of cardiac valves stenosis and incompetence?
- Congenital heart disease (bicuspid valve, atresia)
- Cardiomyopathy (hypertrophic, dilated)
- Aquired
What are the aquired causes of cardiac valve stenosis?
- Rheumatic fever
- MI
- Age related - idiopathic aortic calcific stenosis
- Endocarditis
How can aortic stenosis lead to sudden death?
Heart cannot reach demands, often during exercise. Ventricular hypertrophy
Arrhythmias
Can lead to ventricular fibrilation
What is rheumatic fever?
Immune mediated response to streptococcal infection (3 weeks post) results in damage to connective tissue.
Attacks collagen in heart valves
- Occurs in children 4-16 years
What does aortic regurgitation result in?
- Increased work load to heart
- Left ventricular hypertrophy
- Cardiac failure
- Can occur in the presence of aortic stenosis
What can be the causes of mitral incompetence?
- Cusp damage (rheumatic heart disease - scarring, contraction)
- Chordae (as above)
- Papillary muscle (e.g post MI)
- Valve rings (as above, age)
What heart valve is most commonly damaged by rheumatic fever?
Mitral valve
What can mitral incompetence lead to?
- Pulmonary hypertension
- Right Ventricular hypertrophy
What can cause aortic incompetence?
- MI
- Infective endocarditis
- Rheumatic fever
- Marfan’s syndrome
- Dilation of aortic root (age-related or syphilitic)
- Some rheumatological disorders, e.g rheumatoid arthritis, ankylosing spondylitis
What are the consequences of aortic stenosis?
- Increases the work of the heart
- Left ventricular hypertrophy
- Clinical symptoms
Angina, dyspnoea, syncope, sudden death
What can be the effects of mitral stenosis?
- Restricts blood flow to left ventrical
- Atrial fibrilation
- Back pressure results in pulmonary hypertension
- Heart failure
What can be heard in mitral stenosis?
Opening snap and diastolic murmur
What can be heard in aortic incomptence?
- Diastolic murmur
- Wide pulse pressure, collapsing pulse, angina, left ventricular failure
What can be heard in mitral incompetence?
- Pansystolic murmur
- Mid-systolic click and late systolic murmur in mitral prolaspe
What can cause aortic stenosis?
- Calcific degeneration
- Rheumatic fever
Define infective endocarditis
Infection of valve with formation of thrombotic vegetations
What determines the severity of infective endocarditis
The virulence of organisms determines damage and severity
What can directly cause infective endocarditis via bacteria?
- Dental operations
- Catheterisation
- 10% unknown
- IV drug abuse
In what type of endocarditis can the valves be normal?
Acute native valve endocarditis
What type of endocarditis is more aggressive?
Acute native endocarditis
What organisms most commonly cause acute native endocarditis?
- Virulent organisms, such as Staph aureus and group B streptococci
What organisms most commonly cause subacute native valve endocarditis?
Alpha-haemolytic streptococci, enterococci
What percentage of infective endocarditis cases are prosthetic valve endocarditis?
10 - 20%
What percentage of mechanical and bioprosthetic valves become infected?
5%
What organisms can cause early onset prosthetic valve endocarditis?
- Staph aureus
- Gram-negative bacilli
- Candida species
What organisms can cause late onset prosthetic valve endocarditis?
- Staphylococci
- Alpha-haemolytic streptococci
- Enterococci
What percentage of IV drug abuse endocarditis cases involve the tricuspid valve?
50%
What organism most commonly causes IV drug abuse endocarditis?
Staph. aureus
What percentage of patients with IV drug abuse endocarditis have an underlying valvular abnormality?
25%
How is infective endocarditis treated and prevented?
- Treat strep infection with antibiotics
- Prophylactic cover for invasive procedures e.g dental work
- Replacing damaged valves
