Valvular Heart Disease Flashcards
What are the components and functions of vales
Function - Allow forward flow but to prevent backflow.
Components - Valve ring, cusp, cordae, and papillary muscles (only for tricuspid and mitral)
Name the functional failure in valves
Mitral stenosis or incompetence, aortic stenosis or incompetence. Tricuspid and pulmonary valve stenosis or incompetence but this is less common and less severe.
Define stenosis
Narrowing of valve outlet caused by thickening of valve cusps or increased rigidity or scarring
Define incompetence
Insufficiency or regurgitation caused by incomplete seal when valves close allowing for blood to flow backwards
What are vegitations?
Lesions or growths on your heart valves that occur with endocarditis
When do you hear the valve sounds?
Tricuspid and mitral in systole. Aortic and pulmonary in diastole
What are some of the common generic causes of cardiac valve stenosis and incompetence?
- Congenital heart disease (Bicuspid valve and atresia)
- Cardiomyopathy (Hypertrophic or dilated)
- Acquired (Rheumatic fever, myocardial infarction, age related (calcification) or endocarditis)
What are some risks of aortic stenosis?
Left ventricular hypertrophy, syncope and sudden cardiac death.
Name some aortic stenosis causes
- Calcification of a congenital bicuspid valve,
- Senile/idiopathic calcification degeneration,
- Rheumatic fever
What are consequences of aortic stenosis?
Increased work of the heart leading to ventricular hypertrophy/ Can lead to cardiac failure. Symptoms include dyspnoea, angina and syncope.
What are some causes of aortic incompetence?
- Infective endocarditic,
- Rheumatic fever
- Marfan’s syndrome
What are the consequences of aortic regurgitation?
Increases the volume of blood the heart needs to pump as a portion of it will flow back into ventricles. This increases work which can cause cardiac hypertrophy and can lead to cardiac failure.
What are some causes of mitral incompetence?
Cusp damage - Rheumatic heart disease (scarring, contraction) Marfan syndrome (stretch), Infective endocarditis (perforation).
Chordae - (same causes as above),
Papillary Muscle - Post MI,
Valve ring - same as above and aging.
What are some of the risks of mitral incompetence?
Pulmonary hypertension or right ventricular hypertrophy
What are some of the consequences of mitral stenosis?
Restricts blood flow to left ventricles, atrial fibrillation, back pressure resulting in pulmonary hypertension and finally causes right heart failure
Define infective endocarditis
Infection of valves or endocardium with formation of thrombotic vegetations.
As blood is constantly moving past valves very quickly then its difficult to get build up of chemotactic factors.
Risk factors for infective endocarditis
Valve damage (Especially post rheumatic fever).
Bacteraemia - Presence of bacteria in circulation, can be due to dental work, catheterisation, IV drug abuse.
Immunosuppression
What is Rheumatic fever?
Acute multisystem disease - affecting heart, joints and connective tissue. Normally occurs 3 weeks post streptococcal infection and is an immune mediated rather than direct infection. Real issue as it can cause chronic valve disease decades later.
Describe the composition of a vegetation
Mass of platelets, fibrin, microcolonies of microorganisms (most commonly group D streptococcus, gut commensals and skin strep), and scant inflammatory cells
What are some of the local and systemic complications of infective endocarditis
- Cardiac failure
- Fever
- Splinter Haemorrhages
- Clubbing
- Joint pain
- Haematuria
- Primary kidney
- Lung Disease
Describe Acute Native Vale Endocarditis
Valves may be normal but infected by a very virulent organisms (staph. aureus) meaning it is an aggressive disease
Describe subacute native valve endocarditis
Occurs with abnormal valves and may be indolent but can deteriorate. Can be caused by alpha-haemolytic streptococci and enterococci
Describe features of prosthetic valve endocarditis
- Where mechanical and bio-prosthetic valves become infected (5%).
- Mitral valves more susceptible than aortic.
- Early onset caused by staph.aureus, gram negative bacilli or candida species.
- Late onset caused by alpha-haemolytic streptococci or enterococci
What are some ways to prevent infective endocarditis?
Treat strep infections with antibiotics, for patients with history of rheumatic fever then give prophylactic cover for invasive procedures such as dental work and replace damaged valves.
What are some of the principles of diagnosis and treatment of infective endocarditis
Clinical suspicion and signs, imaging (ECHO) and take many blood cultures. Then treat with IV antibiotics.
