Week 11 Pathology - The Heart Flashcards
What are the three types of cardiomyopathy?
- Dilated cardiomyoptathy
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy
What is the difference between primary and secondary cardiomyopathy?
Primary = confined to myocardium
Secondary = cardiac manifestation of systemic disease (i.e. sarcoidosis, chronic anaemia)
What is the epidemiology and causes of DCM?
20-50 years
Alcohol, genetic, peripartum, sarcoid, haemachromatosis, myocarditis, IHD, HTN
What is the mechanism of HF and morphology associated with DCM?
HFrEF, EF <40%
Dilated/floppy chambers with variable wall thickness, non specific histologic changes
What is the cause of HCM?
Genetic, disorder of sarcomeric proteins, Beta myosin heavy chain most commonly affected –> hypertrophy –> can cause ventricular outflow obstruction in 1/3 cases (where septum bulges and obstructs the aortic valve)
What is the mechanism of HF in HCM?
Impaired compliance of stiff/hypertrophied ventricle –> “diastolic dysfunction/HFpEF
What are the histological features of HCM?
Myocyte hypertrophy
Disorganised arrangement of myocytes
Interstitial fibrosis
What is the cause of restrictive cardiomyopathy?
Wall stiffness caused by myocardial deposition disease (amyloidosis, radiation induced fibrosis, idiopathic)
What are the 3 classifications of cardiomyopathy?
Dilated
Hypertrophic
Restrictive
What are the causes of DCM, and what is the mechanism of heart failure?
IHD, HTN, thyrotoxicosis, anaemia, alcohol, sarcoid
Systolic dysfunction, HFrEF, EF < 40%
What is the cause of HCM?
Sarcomeric protein dysfunction, most commonly Beta myosin heavy chain. Causes haphazard arrangement of myocytes and asymmetrical septal hypertrophy
Causes restrictive cardiomyopathy –> HFpEF
What are the complications of HCM?
Ischaemic: Angina, ACS in absence of CAD
Arrhythmic: AF, VT, Sudden cardiac death
Structural: CHF, mural thrombus, IE of mitral valve
What are the morphological and histological features of HCM?
Morph: asymmetric septal hypertrophy, decreased ventricular chamber size
Histo: hypertrophied myocytes, haphazard arrangement, interstitial fibrosis
What are the causes of restrictive cardiomyopathy?
Cardiac deposition disease –> amyloidosis, radiation induced, idiopathic –> causes stiff, poorly compliant muscle, HFpEF with diastolic dysfunction
What is the morphology of RCM?
Normal ventricular size, non dilated cavities, firm myocardium, but with dilated atria
What is serous pericarditis?
Inflammatory exudate
Causes including viral, ARF, uraemia, SLE
What is fibrinous pericarditis commonly caused by?
Dressler’s syndrome (post MI)
What is suppurative pericarditis caused by?
Bacterial, parasitic, fungal
What is Haemorrhagic pericarditis caused by?
Cardiac surgery, TB, malignancy
What is constrictive pericarditis?
Restricted diastolic dysfunction due to pericardial effusion, commonly associated with post-suppurative or TB pericarditis
What are the most common causes of secondary pericarditis?
MI, cardiac surgery, uraemia
What is Beck’s Triad?
- Hypotension with narrow pulse pressure
- Distended neck veins
- Muffled heart sounds
What is acute rheumatic fever?
Acute, immunologically mediated, multi system disease that occurs post Group A Haemolytic streptococcus infection (pharyngitis, skin)
What is the pathogenesis?
Hypersensitivity reaction caused by antibodies that )(via incidence of molecular mimicry) mistake proteins in myocardium and cardiac valves for strep antigens (M proteins) –> injury mediated by complement, macrophages and T cells
What eponymous term is pathognomonic for ARF?
Aschoff bodies –> aggregates of inflammatory cell in heart muscle
What are the cardiac manifestations of ARF?
Pancarditis
Fibrinous pericardial exudate
Fibrinoid necrosis and fibrin deposition forming valvular vegetations, commonly mitral valve
When does ARF present?
2-3 weeks post strep infection
What is the most common presentation of ARF?
Fevers and migratory polyarthritis
What is the biochemical inclusion criteria required for a diagnosis of ARF?
Serological evidence of previous GAS infection
What mix of criteria are required for meeting threshold of diagnosis?
2 major OR 1 major and 2 minor
What are the major elements of Jones criteria?
- Carditis (clinical or echo)
- Migratory polyarthritis or polyarthralgia
- Subcutaneous nodules
- Erythema marginatum
- Sydenham chorea
What are the minor criteria for ARF?
Fever
Elevated inflammatory markers
Prolonged PR on ECG
What is heart failure?
Inability of the heart to supply adequate blood flow to match metabolic demands of peripheral tissues/organs
List common causes of heart failure?
CAD
IHD
Cardiomyopathy
Chronic HTN
Sepsis
Valvular disease
What is the most common clinical classification of heart failure?
HFrEF
HFpEF
What single change in terms of heart function triggers the compensatory mechanisms associated with heart failure?
Decreased stroke volume
How does the Frank-Starling mechanism relate to heart failure compensation?
Decreased stroke volume –> decreased cardiac output.
Heart utilised Frank-Starling mechanism to increase cardiac output by increasing end-diastolic volume.
What are compensatory neurohumoral changes in the setting of heart failure?
Activation of RAAS
Increased circulating catecholamines
Vasopressin/ADH
Natriuretic peptides
How does heart failure lead to increased blood volume?
- Decreased renal perfusion –> increased renin secretion
- Decreased baroreceptor stretch –> ADH secretion
How does increased blood volume cause problems in heart failure?
Reliance on increased volume to increase preload and therefore CO –> also increased afterload and venous pressures, leading to pulmonary and peripheral oedema.
