Valvular Heart Disease, Endocarditis Flashcards
Is valvular heart disease primary or secondary ?
It can be both.
What proportion of heart failure involve valve disease ?
10% of heart failures involve valve disease
Which valves of the heart are affected by valvular disease ?
All four, but mainly aortic and mitral valve
Give an example of how valvular heart disease could occur secondary to another event.
Dilatation of the heart causing an inability for the valve to close.
Identify the main function of heart valves.
To allow forward flow but prevent backflow.
Identify the main components of valves.
Valve ring
Cusps
Chordae
Papillary muscle (mitral and tricuspid only)
Identify the main functional failures in valves.
Mitral stenosis
Mitral incompetence
Aortic stenosis
Aortic incompetence
Although aortic and mitral valve disease are more common than pulmonary and tricuspid valve disease, are they also more serious ?
Yes, more common and more serious
Are stenosis and incompetence mutually exclusive ?
No, stenosis and incompetence can coexist (but even if they’re both involved, one might be dominant)
Why are pulmonary and tricuspid valves less likely to be affected/why is it less severe in those valves ?
Less involved because under less mechanical stress which also means that any disease affecting the valve is likely to be made much worse in mitral/aortic valve (hence more severe)
Define stenosis.
Narrowing of the valve outlet caused by thickening of valve cusps, or increased rigidity or scarring.
Define incompetence.
Insufficiency or regurgitation (which is what happens) caused by incomplete seal when valves close, allowing blood to flow backwards
Define vegetations and explain their relevance to valvular heart disease.
“any plantlike growth”
Something growing in a valve (typically platelets and fibrin thrombus, sometimes can be calcified scar tissue)
Which phase of the cardiac cycle would you notice aortic incompetence in ?
Diastole
Which phase of the cardiac cycle would you notice aortic stenosis in ?
Systole
Which phase of the cardiac cycle would you notice mitral stenosis in ?
Diastole
Identify general, common causes of cardiac valve stenosis and incompetence.
1) Congenital Heart Disease
- Bicuspid valve (When it should in fact have three cusps. Can be problematic) e.g. in aorta
- Atresia
2) Cardiomyopathy
- Hypertrophic
- Dilated
3) Acquired
- Rheumatic fever
- MI
- Age-related- idiopathic aortic calcific stenosis
- Endocarditis
Which valvular functional failure would a dilated cardiomyopathy result in ?
Incompetence, because the valvular ring would be dilated, so cusps cannot meet anymore
Which valvular functional failure would a hypertrophic cardiomyopathy result in ?
Stenosis or incompetence.
What are the possible risks of aortic stenosis ?
- L ventricular hypertrophy (L ventricle has to push harder)
- Syncope (loss of consciousness)
- Sudden cardiac death
Identify causes of aortic stenosis.
- Calcification of congenital bicuspid valve
- Senile calcific degeneration
- Rheumatic fever (inflammatory holes in cusps resulting in scarring and stenosis)
Identify consequences and clinical symptoms of aortic stenosis.
- Increases work of the heart
- Ventricular hypertrophy
- Causes cardiac failure late in clinical course
Clinical symptoms include:
- Dyspnoea (breathlessness)
- Angina (cardiac chest pain)
- Syncope
Identify the main causes of aortic incompetence.
- Infective endocarditis
- Rheumatic fever
- Marfan’s syndrome (CT too elastic)
- Dilatation of aortic root (age-related or syphilitic)
What are the consequences of aortic regurgitation ?
Increases V of blood to be pumped
Increases work to be done by the heart
Cardiac Hypertrophy
Cardiac Failure
Can aortic regurgitation occur in the presence of aortic stenosis ?
Yes it can.
Identify the main causes of mitral incompetence.
Cusp Damage
- Rheumatic Heart Disease (scarring, contraction)
- Floppy valve & Marfan Syndrome (stretch)
- Infective endocarditis (perforation)
Chordae Damage
- Rheumatic Heart Disease (scarring, contraction)
- Floppy valve & Marfan Syndrome (stretch)
- Infective endocarditis (perforation)
Papillary Muscle Damage
-Post MI
Valve ring Damage
- Age or Hypertension (hence dilated heart, and ring)
- Rheumatic Heart Disease (scarring, contraction)
- Floppy valve & Marfan Syndrome (stretch)
- Infective endocarditis (perforation)
What is the most common cause of mitral incompetence ?
Rheumatic Fever
What are the risks posed by mitral incompetence ?
Pulmonary hypertension
L ventricular hypertrophy
R ventricular hypertrophy
Associate each main valvular heart disease with a kind of murmur.
Aortic stenosis: Ejection systolic murmur
Aortic incompetence: Diastolic murmur
Mitral stenosis: Diastolic murmur
Mitral incompetence: Systolic murmur
Identify the main causes of mitral stenosis.
Congenital (rare) Rheumatic Fever (so rare in developed countries)
What are the risks posed by mitral stenosis ?
- Restricts blood flow to L ventricle
- Atrial fibrillation
- Pulmonary hypertension (due to back pressure)
- Right heart failure
Define infective endocarditis.
Infection (bacteraemia most common) of valve with formation of thrombotic vegetations (organisms within thrombus)
What determines the severity of infective endocarditis ?
Virulence of organisms determines damage and severity
How are different infective endocarditis classified ?
Acute and Sub-Acute
Distinguish between the clinical presentations of acute and sub-acute infective endocarditis.
Acute = Collapse (aggressive disease) Sub-acute = Unwell, possible fever, WBC count might be bouncing up and down (indolent but may deteriorate)
Would blood cultures be conclusive for acute infective endocarditis ? for sub-acute infective endocarditis ?
Acute: Yes
Sub-Acute: Possibly, maybe not
What are the main risk factors for infective endocarditis ?
1) Valve Damage
(all factors of valve damage, especially rheumatic fever)
2) Bacteraemia Dental Catheterisation 10% unknown IV drug abuse
3) Immunosupression
Define rheumatic fever. What is its relation to valve disease ?
Illness which arises as a complication of untreated or inadequately treated strep throat infection (3 weeks post Streptococcal infection, usually pharyngitis). Immune-mediated rather than direct infection.
Chronic valve disease occurs decades late.
What is the single most common acquired risk factor for infective endocarditis ?
Rheumatic fever
Which systems does rheumatic fever affect ?
heart (myocarditis, valvulitis, pericarditis), joints, connective tissue
Describe the demographic distribution of rheumatic fever.
Occurs in children: 4-16 years
What is the timeline of rheumatic fever (once it starts) ?
May occur in recurrent episodes
Describe the composition of a vegetation.
Vegetation = fibrin + platelet (thrombus) +
Whole host of possible organisms within the thrombus (Group D Streptococcus, gut commensals, skin Strep, Candida)
Identify the local and systemic complications of infective endocarditis.
- Clubbing
- Splinter haemorrhages
- Haematuria
- Anaemia
- Renal infarcts/Glomerulonephritis
- Myocarditis
- Cerebral and retina emboli
Distinguish between the state of the valves in acute, and sub-acute infective endocarditis.
ACUTE
– Valves may be normal
SUBACUTE
– abnormal valves
Distinguish between the organisms present in acute, and sub-acute infective endocarditis.
ACUTE
virulent organisms, such as Staph aureus and group B streptococci
SUBACUTE
alpha-haemolytic streptococci, enterococci
What proportion of all endocarditis cases does prosthetic valve endocarditis represent ?
10-20% of cases
What proportion of of mechanical and bioprosthetic valves become infected ?
5% of mechanical and bioprosthetic valves become infected
Does prosthetic valve endocarditis target any valves more than others ?
Mitral are more susceptible than aortic
What organisms are associated with prosthetic valve endocarditis ?
– early onset: Staph aureus, gram-negative bacilli, Candida species
– late onset: staphylococci, alpha-haemolytic streptococci, enterococci
What organism is most associated with infective endocarditis in IV drug users ?
Staph. aureus
Which valve is most affected in infective endocarditis in IV drug users ? Is valvular disease the most common cause of infective endocarditis in IV drug users ?
50% involve the tricuspid valve
No, 75% have no underlying valvular abnormalities
How is infective endocarditis diagnosed, treated and prevented ?
Treatment:
-If Strep infection, antibiotics
Prevention:
- Prophylactic cover for invasive procedures eg dental work
- Replace damaged valves
Diagnosis: • Clinical suspicion • Clinical signs • Imaging – especially echo cardiography (can hint at vegetations in valve, but cannot confirm infective endocarditis) • Blood culture (repeat it)
