Cardiomyopathies

Question 1

What are the three main types of cardiomyopathy?

Answer 1

• Hypertrophic cardiomyopathy
• Dilated cardiomyopathy
• Arrythmogenic cardiomyopathy

Question 2

What is a cardiomyopathy?

Answer 2

A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.

Question 3

Which cardiomyopathy is the most common?

Answer 3

Hypertrophic cardiomyopathy

Question 4

Which cardiomyopathy is most commonly seen following a heart transplant?

Answer 4

Dilated cardiomyopathy

Question 5

Clinical presentation of cardiomyopathy

Question 6

What is hypertrophic cardiomyopathy?

Answer 6

Increased ventricular wall thickness or mass without loading conditions sufficient to cause the observed abnormality.

Question 7

Cause of hypertrophic cardiomyopathy

Answer 7

Most common genetic cardiac disorder and is inherited in an autosomal dominant fashion (although around 50% of cases are sporadic)

Question 8

Three cardinal features of hypertrophic cardiomyopathy

Answer 8

• Hypertrophy (usually asymmetrical left ventricular hypertrophy)
• Myocyte disarray
• Fibrosis

Question 9

Clinical features of hypertrophic cardiomyopathy

Answer 9

• Most people with hypertrophic cardiomyopathy are asymptomatic
• May present with angina, dyspnoea or syncope if left ventricular outflow tract (LVOT) obstruction occurs
• Sudden death is usually caused by arrhythmias or severe LVOT obstruction

Question 10

Managment of hypertrophic cardiomyopathy

Answer 10

1. Manage the LVOT obstruction
2. Prevent sudden cardiac death
   
   • ICD implantation
3. Offer screening
   
   • First degree relatives should be offered ECG and echocardiography

Question 11

How to manage LVOT and SAM?

Answer 11

• Avoid volume depletion as this worsens LVOT obstruction
• First line: beta blocker or rate limiting calcium channel blocker (eg verapamil)
• Second line: surgical myectomy
• Alcohol septal ablation (alcohol injected directly into the coronary artery causing a small iatrogenic MI to reduce septal thickness)
• Heart transplantation may be required in severe cases

Question 12

Dilated cardiomyopathy definition

Answer 12

Dilated cardiomyopathy is characterised by dilation and systolic dysfunction of the left and/or right ventricles.

Question 13

Aetiology of dilated cardiomyopathy

Answer 13

Around 50% of cases are idiopathic but several important associations exist.

• Chronic alcohol consumption
• Genetic (at least 20% are familial)
• Viral infections
• Hypothyroidism
• Peripartum cardiomyopathy
• Chemotherapy (eg doxorubicin, trastuzumab)

Question 14

Clinical features of dilated cardiomyopathy

Answer 14

• Patients may present with symptoms of heart failure, dyspnoea and thromboembolism
• Or patients may be asymptomatic

Question 15

Why is it important to rule our chronic alcohol consumption?

Answer 15

Dilated cardiomyopathy that is secondary to chronic alcohol consummation is potentially reversible.

Question 16

Managment of dilated cardiomyopathy

Answer 16

• Managment of heart failure symptoms
• Anticoaguation
• Some patients may need an ICD or CRT

Question 17

Pathophysiology of restrictive cardiomyopathy

Answer 17

Restrictive cardiomyopathy involves contraction of atria against stiff, non-dilated ventricles with near normal systolic function.

Stiff ventricles lead to impaired diastolic filling, congestive heart failure and reduced cardiac output.

Question 18

Causes of restrictive cardiomyopathy

Question 19

Investigations for restrictive cardiomyopathy

Answer 19

• First line: echo
• Gold standard: endomyocardial biopsy
• CT, MRI and diagnostic angiography are also helpful
• Important to distinguish between constrictive cardiomyopathy and constrictive pericarditis as the latter may be correctable with surgery

Question 20

Managment of restrictive cardiomyopathy

Answer 20

• Treat the underlying cause
• Anticoagulation
• Treat heart failure

Question 21

Arrythmogenic right ventricular cardiomyopathy definition

Answer 21

A form of cardiomyopathy that can present with arrhythmia or sudden death.

Genetic mutations in the desmosomes of the cardiac myocyte lead to eventual fibro-fatty infiltration of the myocardium, leading to impaired RV function.

Question 22

Investigations for Arrythmogenic right ventricular cardiomyopathy

Answer 22

Diagnosis is challenging and requires a combination of ECG changes, echocardiography and cardiac MRI.

ECG shows epsilon wave and T wave inversion on ECG.

Question 23

Management of Arrythmogenic right ventricular cardiomyopathy

Answer 23

Patients should be treated symptomatically and offered ICDs for the prevention of sudden cardiac death.

Question 24

Definition of Takotsubo cardiomyopathy

Answer 24

Also known as broken heart syndrome, is thought to be a catecholamine mediated response to severe stress events.

Question 25

Clinical features of Takotsubo cardiomyopathy

Answer 25

Signs and symptoms may mimic MI but patients have non-obstructive coronary arteries on angiography.

Apical ballooning of the left ventricle is pathognomic on ventriculography.

Question 26

Managment of Takotsubo cardiomyopathy

Answer 26

Usually self limiting, but there is a risk of death due to arrythmia or ventricular free wall rupture.

Most physicians recommend monitoring in the early stages of treatment with beta blockers and ACE inhibitors.