Histo: Vascular and Cardiac Pathology Pt.2 Flashcards
What is the 1-year mortality after an MI?
30%
What is chronic ischaemic heart disease?
- Progressive heart failure due to ischaemic myocardial damage
- Leads to hypertrophied, dilated LV
- Usually due to long-standing atherosclerosis
- Microscopic fibrosis
NOTE: there may be no prior infarction
What is sudden cardiac death?
- Unexpected death from cardiac causes in individuals without symptomatic heart disease or early (1hr) after the onset of symptoms
- Usually due to lethal arrhythmia
What are some underlying conditions that can cause sudden cardiac death?
IHD (90%)
- Acute myocardial ischaemia the usual trigger
- Leads to electrical instability of the conduction system
- This usually occurs at sites of old MI scars
Non-atherosclerotic cause (10%) - e.g. long QT
List some causes of heart failure.
- Ischaemic heart disease
- Valve disease
- Hypertension
- Myocarditis
- Cardiomyopathy
List some complications of heart failure.
- Sudden death
- Arrhythmias
- Systemic emboli
- Pulmonary oedema with superimposed infection
- Hepatic cirrhosis (nutmeg liver)
Outline the histology of heart failure.
- Dilated heart
- Scarring and thinning of the walls
- Fibrosis and replacement of ventricular myocardium
What are cardiomyopathies?
Intrinsic problems of the heart muscle
What is dilated cardiomyopathy?
Caused by progressive loss of myocytes leading to a dilated heart
Systolic dysfunction
List some causes of dilated cardiomyopathy.
- Idiopathic
- Genetic: familial, haemochromatosis
- Infection: post-viral myocarditis
- Toxins: alcohol, drugs (cocaine, doxorubicin)
What is hypertrophic cardiomyopathy?
- Thickening of the heart muscle
- Family history in 50% of cases
- Leads to ventricular outflow obstruction and arrhythmia
Diastolic dysfunction
NOTE: some are associated with a specific abnormality in the beta-myosin heavy chain
What is restrictive cardiomyopathy?
Impaired ventricular compliance - diastolic dysfunction, near-normal systolic function
Causes:
- Amyloidosis
- Sarcoidosis
- Haemochromatosis
What is chronic rheumatic heart disease caused by?
Antigenic mimicry
Caused by immune cross-reactivity of group A streptococcal antigens and cardiac valves
Which valve is most commonly affected in rheumatic heart disease?
Mitral valve
What is the most common cause of aortic stenosis?
Aortic valve sclerosis - calcification (age-related)
List some causes of aortic regurgitation.
Valvular defect
- Congential bicuspid valve
- Age-related degeneration
- RHD
- Endocarditis
Aortic dilatation
- Dissection
- Chronic hypertension
- Connective tissue diease e.g. Marfan’s
- Aortitis e.g. syphilis
Which valves are most commonly affected by endocarditis?
- Left-sided valves (mitral > aortic)
- If IVDU, then tricuspid
What are the two different types of true aneurysms?
- Saccular
- Fusiform
Describe the histology of rheumatic heart disease
- Beady fibrous vegetations (verrucae)
- Aschoff bodies (small giant-cell granulomas)
- Anitschkov myocytes (regenerating myocytes)
Acute vs subacute endocarditis?
Causative organism:
- Acute = staph aureus, strep pyogenes
- Subacute = strep viridans
Virulence:
- Acute = high
- Subacute = low
Vegetation morphology:
- Acute = larger and more localised
- Subacute = friable, soft thrombi, few mm in size
Spread:
- Acute = aorta
- Subacute = chordae
Treatment for infective endocarditis?
Acute:
- MSSA - fluclox
- MRSA - rifampicin + vancomycin + gentamicin
Subacute:
- Benzylpenicillin + gentamicin, or vancomycin for 4wks
What is the most common cause of constrictive pericarditis?
TB
What is the most common cause of myocarditis?
Viral infection
What is the most common primary tumour in the heart?
Myxoma
