5. Cardiomyopathies

Question 1

What does cardiomyopathy refer to?

Answer 1

Primary heart muscle disease - often genetic

Question 2

Name 3 cardiomyopathies.

Answer 2

1. Hypertrophic cardiomyopathy (HCM)
2. Dilated cardiomyopathy (DCM)
3. Arrhythmogenic right/left ventricular cardiomyopathy (ARVC/ALVC)

Question 3

What is the usual inheritance pattern for cardiomyopathies?

Answer 3

Autosomal dominant; off-spring have a 50% chance of being affected.

Question 4

What investigations might you carry out in cardiomyopathy?

Answer 4

CXR, ECG, echo.
Cardiac MR

Question 5

Describe the pathophysiology of HCM.

Answer 5

Systole is normal but diastole is affected - diastolic heart failure
I.E. strong contractions but relaxation = issue!!

The heart is unable to relax properly due to thickening of the ventricular walls.

At cellular level -> myofibrillar disarray

Question 6

Give 3 symptoms of HCM.

Answer 6

1. Angina.
2. Dyspnoea.
3. Syncope.
4. Palpitations.

Question 7

What can cause HCM?

Answer 7

Sarcomeric gene mutations e.g. beta myosin, troponin T mutations. About 1 in 500 people are affected.

Question 8

For HCM, what are the chances of it being caused by genetics and other factors?

Answer 8

50% = autosomal dominant
50% = sporadic

Question 9

What is the major consequence of HCM?

Answer 9

Sudden cardiac death in young people

Question 10

What might an ECG look like from a person with HCM?

Answer 10

1. Large QRS complexes.
2. Large inverted T waves.

Question 11

Treatment of HCM

Answer 11

Beta blockers/CCBs to control symptoms.

Anticoagulate to prevent embolism.

Implantable defibrillator

Question 12

Describe the pathophysiology of DCM.

Answer 12

Ventricular dilation and dysfunction = poor contractility
I.E. poor contractions + thin walls

Question 13

What can cause DCM?

Answer 13

Cytoskeletal gene mutations

Question 14

Give 3 causes of DCM.

Answer 14

Alcohol, hypertension, haemachromatosis, viral infection, autoimmune, congenital.

Question 15

Give 3 symptoms of DCM.

Answer 15

DCM usually presents with symptoms similar to those seen in heart failure:

1. Breathlessness.
2. Tiredness.
3. Oedema.

Question 16

Give 3 clinical features of DCM.

Answer 16

Dyspnoea, embolism or arrhythmia, displaced apex beat, S3 gallop, pleural effusion, oedema, jaundice, ascites.

Question 17

Treatment of DCM

Answer 17

Bed rest.
Diuretics, digoxin, ACE inhibitors.
Biventricular pacing/implantable cardiac defibrillator
Heart transplant.

Question 18

What can cause ARVC/ALVC?

Answer 18

Desmosome gene mutations.

Question 19

Describe the pathophysiology of ARVC/ALVC.

Answer 19

Desmosomes attach cells via their intermediate filaments.

Desmosome mutations lead to myocytes being pulled apart -> muscle undergo programmed cell death.
Ventricles are replaced with fatty, fibrous tissue.

Gap junctions are affected too.

Question 20

Give a sign of ARVC/ALVC.

Answer 20

Ventricular tachycardia.

Question 21

What might an ECG look like from a person with ARVC/ALVC.

Answer 21

Epsilon waves.

Question 22

What is restrictive cardiomyopathy (RCM)?

Answer 22

Rigid myocardium -> poor dilation of the heart -> restricting diastolic ventricular filling

Question 23

Give 2 causes of RCM.

Answer 23

Amyloidosis. haemachromatosis. sarcoidosis. scleroderma. idiopathic.

Question 24

What is the commonest cause of restrictive cardiomyopathy?

Answer 24

Amyloidosis (extra-cellular deposition of an insoluble fibrillar protein - amyloid).

Question 25

Give 3 clinical features / symptoms of RCM.

Answer 25

Raised JVP. oedema, ascites, features of RVH.

Question 26

Investigations for RCM diagnosis.

Answer 26

Cardiac catheterisation.