Cardiomyopathy

Question 1

What is cardiomyopathy?

Answer 1

Broad-brush term for primary disease of the myocardium.

Question 2

What are the different types of cardiomyopathy? (x3)

Answer 2

Dilated, hypertrophic, or restrictive.

Question 3

What is the aetiology of dilated cardiomyopathy? (x8)

Answer 3

• Mostly idiopathic
• Post-viral myocarditis
• Alcohol
• Drugs such as doxorubicin or cocaine
• Familial (usually autosomal dominant)
• Thyrotoxicosis
• Haemochromatosis
• Peripartum

Question 4

What is the aetiology of hypertrophic cardiomyopathy?

Answer 4

Up to 50% of cases are genetic (autosomal dominant) with mutations in beta-myosin, troponin T or alpha-tropomyosin (components of the contractile apparatus).

Question 5

What is the aetiology of restrictive cardiomyopathy? (x3)

Answer 5

Amyloidosis, sarcoidosis, haemochromatosis

Question 6

What is the pathophysiology of dilated cardiomyopathy?

Answer 6

Left ventricular remodelling which manifests as increasing left ventricular end-diastolic and end-systolic volumes, wall thinning, and change in chamber geometry to a more spherical and less elongated shape. Two compensatory responses are subsequently employed: Frank-Starling law (stretch and increased volumes leads to increased contractility), and SNS and RAAS feedback.

Question 7

What is the pathophysiology of restrictive cardiomyopathy?

Answer 7

Myocardium becomes rigid but not thickened so heart is restricted from stretching and filling properly. Preload increases, and so blood flow is reduced and blood volume that would normally enter heart is backed up in the circulatory system.

Question 8

What is the epidemiology of cardiomyopathy: Prevalence of each?

Answer 8

Dilated and hypertrophic have 0.05-0.2% prevalence; Restrictive is rare.

Question 9

What are the symptoms of dilated cardiomyopathy?

Answer 9

• Symptoms of heart failure
• Arrythmias
• Thromboembolisms
• Family history of sudden death

Question 10

What are the signs of dilated cardiomyopathy? (x4)

Answer 10

• Raised JVP
• Displaced apex beat
• Functional mitral and tricuspid regurgitations
• Third heart sound

Question 11

What are the symptoms of hypertrophic cardiomyopathy?

Answer 11

• Usually none.
• Syncope
• Angina
• Arrythmias
• Family history of sudden death

Question 12

What are the signs of hypertrophic cardiomyopathy? (x3)

Answer 12

• Jerky carotid pulse
• Double apex beat
• Ejection systolic murmur

Question 13

What are the symptoms of restrictive cardiomyopathy?

Answer 13

• Dyspnoea
• Fatigue
• Arrythmias
• Ankle or abdominal swelling
• Family history of sudden death

Question 14

What are the signs of restrictive cardiomyopathy? (x6)

Answer 14

• Raised JVP (Kussmaul’s sign also present)
• Palpable apex beat
• Third heart sound
• Ascites
• Ankle oedema
• Hepatomegaly

Question 15

What are the investigations for cardiomyopathy? (x5)

Answer 15

• CXR: may show cardiomegaly and signs of heart failure
• ECG
• Echocardiography
• Cardiac catheterisation: may be necessary for measurement of pressures
• Endomyocardial biopsy: may be helpful in restrictive cardiomyopathy

Question 16

What does an ECG show for each of (i) dilated, (ii) hypertrophic, and (iii) restrictive cardiomyopathy?

Answer 16

1. Non-specific ST changes, conduction defects, arrythmias
2. Left-axis deviation, signs of left ventricular hypertrophy (increased voltage), Q waves in inferior and lateral leads, non-specific ST changes, conduction defects, arrythmias
3. Low voltage complexes, non-specific ST changes, conduction defects, arrythmias

Question 17

What does echocardiography show for each of (i) dilated, (ii) hypertrophic, and (iii) restrictive cardiomyopathy?

Answer 17

1. Dilated ventricles with global hypokinesia
2. Ventricular hypertrophy
3. Non-dilated non-hypertrophied ventricles. Atrial enlargement, preserved systolic function, diastolic dysfunction, granular appearance of myocardium in amyloidosis