Cardiomyopathy and Pathology of the Heart

Question 1

What are the main classifications of cardiomyopathy?

Answer 1

Dilated
Hypertrophic
Restrictive

Question 2

The heart itself actually ENLARGES in dilated cardiomyopathy, whilst the chambers dilate. TRUE/FALSE?

Answer 2

TRUE

Question 3

50% of dilated cardiomyopathy is caused by genetic factors. TRUE/FALSE?

Answer 3

TRUE
- mutations in genes that encode heart muscle proteins
=> Desmin, dystrophin (muscular dystrophy) etc

Question 4

Other than genetics, what can cause dilated cardiomyopathy?

Answer 4

• Toxins (e.g. chemotherapy agents)

- alcohol

Question 5

Describe the clinical picture of patients with dilated cardiomyopathy

Answer 5

• essentially like heart failure (as heart is an ineffective pump)
• SOB
• poor exercise tolerance
• Low ejection fraction

Question 6

What happens to the heart muscle in hypertrophic cardiomyopathy and what does this eventually cause?

Answer 6

• Big solid hearts => strong muscle contraction
• Diastolic dysfunction as heart cant relax properly (systolic contraction is fine)
• Eventually outflow obstruction
• may cause sudden death in athletes

Question 7

The majority of cases of hypertrophic cardiomyopathy are die to a genetic cause. TRUE/FALSE?

Answer 7

TRUE

• Beta myosin heavy chain
• Myosin binding protein C
• Alpha tropomyosin

Question 8

Describe the macroscopic appearance of hypertrophic cardiomyopathy

Answer 8

• Bulging interventricular septum
• Outflow tract obstruction
• LV lumen reduced

Question 9

Describe the microscopic/histological appearance of hypertrophic cardiomyopathy?

Answer 9

Disorganised myofibres (swirls)

Question 10

What happens in restrictive cardiomyopathy to impair the function of the heart?

Answer 10

Stiff heart
=> Doesn’t fill well in diastole (diastolic dysfunction)
- Can look normal
- BUT may have Biatrial dilatation as a result of back pressure

Question 11

What can cause a restrictive cardiomyopathy?

Answer 11

• Deposition of something in myocardium

e. g. iron, amyloid, sarcoid, tumour, fibrosis (post-radiation)

Question 12

What are the two different types of amyloidosis that can be found in the body?

Answer 12

AA – relate to chronic diseases like rheumatoid

AL – light chains, abnormal immunoglobulin

Question 13

How is amyloid identified in the heart?

Answer 13

Waxy pink material
Stains positively for “congo red”
Exhibits apple green birefringence

Question 14

What is Arrhythmogenic Right Ventricular Dysplasia?

Answer 14

• Genetic disease – autosomal dominant
• Right ventricle becomes largely replaced by fat

Causes:

• Syncope and funny turns
• Arrhythmia
• Occasional sudden death

Question 15

What can cause a non-infectious myocarditis?

Answer 15

Immune mediated hypersensitivity reactions
=> Hypersensitivity to infection – Rheumatic fever after strep sore throat
=> Hypersensitivity to drugs – Eosinophilic myocarditis
=> Systemic Lupus Erythematosus (SLE)

Question 16

Primary tumours of the heart are rare. TRUE/FALSE?

Answer 16

TRUE

• as cardiac muscle cells are at END of their differentiation
• atrial myxoma is most common tumour
• BENIGN

Question 17

What metastatic tumours may reach the heart?

Answer 17

• Metastatic malignant melanoma

- direct invasion by Lung/oesophagus

Question 18

Atrial myxoma may cause what complications for the patient?

Answer 18

• ball/valve obstruction
• tumour emboli
• develop endocarditis
• Assoc. with systemic fever and malaise – IL-6