Week 1 - CVS Flashcards
ARF, RHD, IE, Cong. Heart Disease, CMP
Describe septum appearance in Hypertrophyic CMP
Irregular thickening of septum –> becomes abnormally large (due to abnormal B-myosin) –> therefore ventricular lumen becomes very narrow (like a BANANA)
What are complications of valve replacement?
- Tissue Valves –> degeneration requiring a 2nd operation
2. Mechanical Valves –> need for anticoagulant therapy to prevent thrombus formation
What is NBTE?
“Non-Bacterial Thrombotic Endocarditis”
- thrombus formation on valves (hypercoagulable state, DIC, malignancy, etc.)
- may cause strokes or secondary bacterial infections
What are Libman-Sacks?
Sterile immune complex vegetations seen in autoimmune disorders (e.g. SLE)
What are the risk factors and complications for infective endocarditis in RHD?
Risk Factors:
- poor dental hygiene
- systemic sepsis
- diabetes
- immunosuppression
- trauma/surgery
- IVDU
Complications:
- septic embolism
- septicaemia
- renal/spleen infarcts
What is the aetiology of mitral valve prolapse?
- MI
- Primary 3-5% congenital degeneration
- Marfan’s Syndrome –> fibrillin gene mutation causing abnormal connective tissue
What is the morphology of myocarditis?
- inflammation
- lymphocytes
- fibrosis (late)
What are the clinical features of myocarditis?
- pain
- fever
- arrhythmias
- CHF–> sudden death :(
What are the causes of myocarditis?
Viral: - enterovirus, CMV, EBV, HIV
Bacterial: - diptheria, leptospirosis, Lyme’s disease
Parasitic: - trypanasoma, toxoplasmosis, trichinosis
Other: - Immune (SLE), ionising radiation, drugs (e.g. doxorubicin)
What type of dysfunction is restrictive CMP?
Diastolic dysfunction –> normal sized but impaired diastolic filling due to stiff firm ventricles
What are the gross features of restrictive CMP?
- normal sized ventricles/rarely enlarged
- myocardium is firm/rigid
What are the causes of restrictive CMP?
- idiopathic, iron deposition
- AMYLOIDOSIS –> amyloid deposition
- endomyocardial fibrosis –> children, helminths, malnutrition, eosinophilia
- loeffler endomyocarditis –> adults, mural thrombi, hypereosinophilia?
What type of dysfunction is hypertrophic CMP?
Diastolic dysfunction –> rigidity of myocardium results in low stroke volume/cardiac output
What is the cause of hypertrophic CMP?
100% genetics - sarcomere dysfunction (autosomal dominant mutation in B-myosin)
-cause of sudden cardiac death in young :(
What is the microscopy of hypertrophic CMP?
- hypertrophy
- disorientation of myofibres
- fibrosis
What is ARVC?
“Arrhythmogenic Right Ventricular Cardiomyopathy”
- type of dilated CMP (RARE)
- inherited, thin, dilated RV with complete loss of muscle (replaced by fibrous wall)
- arrhythmogenic, VT & fibrillation
What type of dysfunction is dilated CMP?
Systolic dysfunction –> heart cannot properly contract and consequently becomes weak due to a structural abnormality (cytoskeleton dystrophin)
What is the main cause of secondary/acquired dilated CMP?
alcohol abuse (N.B. genetics = 20%)
Describe the gross features of a heart with dilated CMP?
- flabby
- enlarged
- 4-chamber dilatation
- mural thrombi –> can cause a stroke
What happens to the LV ejection fraction in dilated CMP?
LVEF < 25% –> slowly progressive CHF
What is cardiomyopathy?
intrinsic myocardial dysfunction due to structural or electrical abnormality without significant inflammation (otherwise it would be called myocarditis)
What is Coarctation of aorta? And what are the 2 types?
congenital disorder that results in narrowing of the aorta.
- Infantile/Pre-ductal
- narrow aorta with patent ductus arteriosus –> cyanosis of lower half of body and early death :( - Adult/Post-ductal
- closed PDA, slight aorta narrowing –> upper extremity HTN with lower limb claudication
What is the only instance in which a patient can survive with transposition of the great arteries (TGA)?
if there is an associated VSD
What is Eisenmenger’s complex?
Reversal of a shunt (i.e. ASD) with cyanosis - from R –> L
What can occur in ASD?
asymptomatic till adulthood - usually a small murmur.
-CHF, pulmonary HTN (late/rare) –> RVH can result from pulm HTN
What are the complication of ASD?
- Eisenmenger’s complex
- Infective endocarditis and paradoxical embolisation (thrombus traveling from one side to the other)
What is patent foramen ovale?
-lack of fusion of septum primum and spetum secundum
-NOT and ASD
-80% close in first 2yrs of life
20% remain patent after 2yrs –> temporary L-R shunt (increased right sided pressure)
When do congenital heart defects occur in utero?
4-9wks gestation (during organogenesis)
What is the etiology of congenital heart diseases?
- 80% = unknown
- 20% = alcohol/drugs, rubella, diabetes, vitamin def.
Outline fetal circulation
- non functional lungs
- maternal blood –> umbilical veins to right side –> shunt to left by : ductus arteriosus, foramen ovale and ductus venosus (liver)
What are the valve problems that cause:
- pan-systolic murmur
- mid-diastolic murmur
- ejection systolic murmur
- early diastolic murmur
- Mitral regurgitation - often radiates to axilla
- Mitral stenosis - opening snap
- Aortic stenosis - radiates to carotids; systolic ejection click
- Aortic regurgitation - heard best with pt. leaning forward
What are the complications of ARF + RHD?
ARF:
- arrhythmia
- cardiac hypertrophy
- heart failure
RHD:
- arrhythmia
- AF –> thromboembolism
- infective endocarditis
- heart failure
What are mitral facies and why do they occur?
butterfly rash over nose and cheeks occurring in mitral stenosis patients
- occurs due to chronic hypoxemia and cutaneous vasodilation
What are gross and microscopic features of ARF?
Gross:
-Pancarditis (Pericarditis –> fibrinous; Myocarditis –> T-cell inflamm; Endocarditis –> vegetations)
Micro:
-Aschoff body (fibrinoid necrosis, macrophages/giant cells, t lymphocytes)
Outline pathogenesis of rheumatic fever
- Susceptible host (ATSI; children 5-15)
- Environmental factors –> overcrowding, nutrition, repeated GAS infections
- ARF develops 2-3wks following pharyngitis as development of autoimmunity needs time for T-cell proliferation
- Molecular mimicry (cross-reactivity with GAS M protein)
- T - cell mediated autoimmune response –> deposition of cross-reactive Ab –> vegetations, aschoff bodies, fibrosis
- Repeated ARF attacks + fibrosis –> yrs –> chronic RHD!
What is rheumatic fever?
- multisystem, autoimmune, inflammatory disorder that affects heart, skin, brain and joints
- follows a GAS infection
What is required clinically for a Dx. of infective endocarditis according to Dukes’ Criteria?
2 major OR 1 major + 3 minor OR 5 minor
What are the major and minor criteria for Dukes Criteria for infective endocarditis?
Major:
- blood culture for IE
- evidence of endocardial involvement (+ ECHO)
Minor:
- predisposition (IVDU/heart condition)
- fever (>38)
- vascular phenomena (Janeway’s lesions, arterial emboli)
- immunologic phenomena (glomerulonephritis, osler’s nodes, roth’s spots)
- microbiological evidence
- echocardiographic findings
True or False?
Clinical features of myocarditis can mimic those of acute MI
True
What is the most common cause of myocarditis?
Viral infections
-esp. enteroviruses (coxsackie A+B)
What is the key feature of syphilic heart disease?
Aortitis
What is stress (takotsubo) CMP?
acute, reversible LV systolic dysfunction
- caused by severe stress/emotional trauma
- AKA broken heart syndrome
What is Cor Pulmonale?
R-sided heart failure secondary to lung disease (i.e. COPD/pulmonary hypertension)
How does restrictive CMP cause heart failure?
stiff ventricular walls –> decreased ventricular compliance –> restricted ventricular filling –> decreased diastolic volume of one/both ventricles –> diastolic dysfunction –> HEART FAILURE
What is the most common cause of cyanosis in infancy?
Tetralogy of Fallot
What murmur is heard in a VSD?
Loud pansystolic murmur + thrill
How does dilated CMP cause heart failure?
Dilatation of all 4 chambers –> hypertrophy occurs with impaired contraction of LV –> systolic dysfunction –> HEART FAILURE (LVEF < 25%)
Clinically, what do endocarditis, myocarditis and pericarditis each give rise to?
Endocarditis –> murmurs
Myocarditis –> arrhythmias
Pericarditis –> pericardial rub
Why is there shortening/fusion of chordae tendinae in RHD?
INFLAMMATION
- andiogenesis and fibrogenesis factors attracted to valve inflammation cause constant healing and scarring of chordae tendinae which overtime shorten as a result (think of how a scab shortens with time)
- also the reason why BVs are present in abnormal RHD valves
What is the pathognomonic feature of ARF?
Aschoff Bodies
What is the most characteristic serum finding in ARF?
Increased ASO titre (Anti-Streptolysin O)
-Abs against streptolysin O which is a substance produced by GAS bacteria.
What is the pathogenesis of SOB in RHD?
Mitral stenosis –> backlog of blood from LA to lungs –> increased pulmonary hydrostatic pressure –> fluid in lungs –> SOB
True or False?
Cardiac tamponade is a complication of MI
True
How can mitral stenosis lead to RVH/Heart failure?
- Stenotic valve = decreased blood flow from LA –> LV
- Therefore increase LA presssure –> increased pulmonary venous pressure –> pulmonary hypertension –> RVH/Heart failure
How can mitral stenosis lead to AF?
Increased LA pressure due to decreased blood flow from LA to LV –> LA enlargement –> further travel required for impulses which can cause circus impulses –> AF
What is the pathogenesis of mitral facies?
Dilation of capillaries due to low CO in mitral stenosis
How can MI cause mitral regurgitation?
Infarct can prevent papillary muscles from contracting and closing the valves properly
What axis deviation on an ECG occurs in mitral regurgitation?
Right
What is a bifid P wave and when is it commonly seen?
- biphasic P wave
- seen in LA enlargement (due to mitral stenosis commonly)
What are complications of infective endocarditis?
- septic embolism
- septicaemia
- glomerulonephritis
- splenomegaly
- arrhythmias
Compare the 2 types of endocarditis
Acute Endocarditis :(
- rare, elderly, IVDU
- occurs on normal valves
- highly virulent bacteria (S.aureus)
- necrotising, destructive lesions
- sudden onset (abrupt fever, fatigue, weakness)
- poor prognosis
- increased mortality
Sub-acute Endocarditis :)
- common, any age
- occurs on abnormal valves
- less virulent bacteria (S.viridans)
- less destructive lesions
- slow onset (wks –> mths)
- good prognosis (cure with antibiotics)
- decreased mortality
What additional sound is heard in mitral stenosis?
Opening snap
When is non-systolic ejection click and systolic ejection click heard?
Non-systolic –> mitral valve prolapse
Systolic –> aortic stenosis
True or False?
Mitral valve prolapse is more common in males
False - females
What is the gross appearance of aortic valve calcification?
Thick, irregular, fibrosed valve with nodules of calcification
What is the etiology of aortic valve calcification and what can result from it?
- progressive age-associated “wear and tear”
- congenital bicuspid aortic valves increased risk
- with time can cause LVH and failure
What is the most common cause of aortic valve stenosis?
Aortic valve calcification
What are the 4 components to Tetralogy of Fallot?
- VSD
- RVH (as a result)
- Pulmonary stenosis
- Overriding aorta
Therfore R–>L shunt with cyanosis and clubbing
What is the murmur heard in patent ductus arteriosus?
Harsh, machinery-like murmur
Which congenital heart defect is the commonest at birth?
Ventricular Septal Defect
-BUT –> 50% of cases close without therapy - thus ASDs are the most common congenital defects overall
What are Anitschkow cells?
- Activated macrophages found within the aschoff bodies of rheumatic heart fever patients on microscopy.
- They have a characteristic caterpillar or owl-eyed nuclei appearance
Why do patients receive long tern antibiotic Tx. after ARF but not during ARF?
- ARF = autoimmunt disease NOT an infection
- antibiotic treatment given after ARF to prevent RHD developing by stopping recurrent attacks of endocarditis
What are MacCallum plaques?
- occur in chronic RHD
- rough, fibrous plaques in LA caused by regurgitation of jets of blood flow through valve due to mitral stenosis/regurgitation
What are the gross features of valves in RHD?
- leaflet thickening
- commisural fusion (fish-mouth)
- shortening, thickening and fusion of chordae tendinae
Why is ARF incidence increased in children (esp. 5-15yrs)?
early exposure to environmental factors
What is an Aschoff body?
small granulomatous lesions seen in ARF patients consisting of: - fibrinoid necrosis of collagen, macrophages & giant cells, T lymphocytes
True or False?
Aschoff bodies are seen in RF but NOT RHD
True
Which valves are most commonly affected in ARF and why?
- mitral and aortic valves (increased mitral)
- exposed to the highest pressure of all the valves thus increased damage
What is the pathogenesis of vegetations/endocarditis in ARF?
- Abs attack collagen which is normally covered by endocardial layer
- Edges of valves which constantly hit each other begin to form small ulcers which expose underlying collagen allowing Abs to bind
- Platelet agglutination results at valve border surface
- Platelets + Ulcers = VEGETATIONS
What is the pathogenesis of pericarditis in ARF?
- fibrinogen leaks out of BVs and clots on pericardial surface forming fibrin deposits and threads
- “Bread and Butter” pericarditis –> pericardial rub as it is no longer smooth
- result of T cell autoimmunity
- marked vasodilation and oedema in pericardial sac
Describe features of ARF on CXR
- cardiomegaly
- opacities in lungs from pulmonary oedema
What are the major and minor criteria for ARF according to Jones’ criteria?
Major:
- pancarditis
- migratory polyarthritis
- erythema nodosum
- sydenham’s chorea
- subcutaneous nodules
Minor:
- fever
- prolonged PR interval
What are the diagnostic requirements for ARF?
- 2 major criteria OR 1 major + 2 minor criteria
- PLUS evidence of a preceding GAS infection
Describe appearance of normal heart valves compared to RHD valves
Normal:
- avascular
- transparent
- thin
- elastic/flexible
RHD:
- vascular
- fibrous/calcification
- thick
- scarred
- stenotic and fixed (MS/MR)
What are the 3 etiological factors for rheumatic fever?
- Genetics –> ? (increased in ATSIs)
- Environment –> GAS infection - overcrowding, poor nutrition, poor housing/sanitation, etc.
- Autoimmunity –> T-cell; Anti-DNAse B
