Pathology Flashcards
Cardiomyopathy
Any disease of the cardiac muscle. It often results in changes in the size of the heart and thickness of the heart
Classification of cardiomyopathy
Dilated, hypertrophic, restrictive, arrhythmogenic
What is dilated cardiomyopathy
Big heart - 2 or 3 times normal size. Heart is flabby and floppy
Causes of dilated cardiomyopathy
Genetics, toxins, alcohol, doxurubicin (chemotherapy agent), cardiac infection, pregnancy
Clinical features of dilated cardiomyopathy
General picture of heart failure, SOB, poor exercise tolerance, low ejection fraction
What is hypertrophic cardiomyopathy
Big solid hearts with thickened myocardium
What sort of dysfunction does hypertrophic cardiomyopathy result in?
Diastolic dysfunction - heart can’t relax, eventually resulting in outflow obstruction
Causes of hypertrophic cardiomyopathy
Most are genetic
Types of genes responsible for hypertrophic cardiomyopathy
Beta myosin heavy chain, myosin binding protein C, alpha tropomyosin
Interventricular septum and LV lumen in hypertrophic cardiomyopathy
Bulging interventricular septum and LV luminal reduction
Myocytes in interventricular septum
Swirling pattern
What is restrictive cardiomyopathy?
Stiff heart causing lack of compliance
What sort of dysfunction does restrictive cardiomyopathy result in?
Diastolic due to heart not filling well
What causes biatrial dilatation in restrictive cardiomyopathy?
Back pressure
Causes of restrictive cardiomyopathy
- Deposition of something in the myocardium
- Metabolic byproducts – iron
- Amyloid
- Sarcoid – multi system granulomatous disorder
- Tumours
- Fibrosis following radiation
What is amyloid?
Abnormal deposition of abnormal protein
Waxy pink material
Why can’t the body get rid of amyloid?
It is insoluble to any of the body’s enzymes
Classification of amyloid
- AA – relate to chronic diseases like rheumatoid
- AL – light chains, abnormal immunoglobulin
- Haemodynamically associated – beta 2 microglobulin
- Familial forms: transthyretin
- Diabetes
- Alzheimer’s
What colour does amyloid stain on a histological slide?
“congo-red” and exhibits apple green birefringence
Which type of cardiomyopathy is amyloid associated with?
Restrictive cardiomyopathy
Arrythmogenic right ventricular dysplasia - what is it?
Genetic disease - autosomal dominant with low penetrance - which causes the right ventricle to be largely replaced by fat and it appears big and floppy. There is near total replacement of the ventricular wall by fat
Symptoms of arrythmogenic right ventricular dysplasia
Syncope and ‘funny turns’, arrhythmias
What does myocarditis look like?
‘Beefy’ myocardium
Causes of infectious myocarditis
- Coxsackie A and B
- ECHO virus
- Many other viruses
- Chaga’s diesea (parasitic cause)
- Lyme’s disease (parasitic cause)
- HIV (very rare subcause)
