🫀🫁Cardio & Resp🫀🫁 - Cardiomyopathies

Question 1

What are the 3 different types of cardiomyopathy?

Answer 1

Dilated
Hypertrophic
Restrictive

Question 2

What is dilated cardiomyopathy (DCM)?

Answer 2

Dilation of left ventricle - reduced contractility
Typically global hypokinesis
Reduced systolic function - reduced ejection fraction
Classified as heart failure with reduced ejection fraction (HFrEF)

Question 3

What are the most common causes of DCM?

Answer 3

Idiopathic
Genetic
Toxins (alcohol, cardiotoxic chemotherapy)
Pregnancy (peripartum cardiomyopathy)
Viral infections (myocarditis) Tachycardia-related cardiomyopathy
Thyroid disease
Muscular dystrophies

Question 4

How is dilated cardiomyopathy managed?

Answer 4

Goal is to lower blood pressure
Sodium-glucose transporter reuptake inhibitor - e.g. dapagliflozin and empagliflozin - first line
Medical heart failure therapy - ACE inhibitors, beta-blockers, mineralocorticoid receptor antagonists
Diuretics for fluid overload
Anticoagulation for atrial fibrillation
Cardiac devices

Question 5

What are the future implications for DCM patients?

Answer 5

Risk of heart failure hospitalization
Cardiac arrhythmias
Risk of sudden cardiac death due to ventricular arrhythmia

Question 6

What are the clinical signs and symptoms of heart failure?

Answer 6

Oedema is key distinguishing feature

Question 7

How does left and right heart failure present differently?

Answer 7

Right heart failure - peripheral oedema e.g. leg swelling, raised jugular venous pressure
Left heart failure – pulmonary oedema

Question 8

Why do left and right heart failure produce their respective symptoms, with respect to oedema?

Answer 8

Left heart failure - lack of output from left side to the aorta, blood is backed up into the lungs - pulmonary oedema
Right heart failure - lack of output from right side to the lungs, blood is backed up to the body, especially pronounced in feet due to gravity - peripheral oedema

Question 9

What is hypertrophic cardiomyopathy (HCM)?

Answer 9

A genetic disorder characterised by left ventricular hypertrophy
Missense mutation in at least 1 of the 10 genes that encode the proteins of the sarcomere
Majority of patients asymptomatic, some present severely with dyspnoea, angina, and syncope - even sudden death

Question 10

What is the cause of HCM in most cases?

Answer 10

Genetic condition

Question 11

What is the pathophysiology of HCM?

Answer 11

Genetic, storage diseases, neuromuscular or mitochondrial disorders, malformation syndromes
Leads to thickening and disarray of left ventricle - frequently involves the ventricular septum

Question 12

How can HCM lead to sudden cardiac death

Answer 12

Disorganised myocytes can interrupt electrical signals
Leads to ventricular fibrillation and cardiac death

Question 13

What are the different forms of HCM?

Answer 13

Obstructive and non-obstructive
Categorised based on whether the hypertrophy obstructs the flow of blood out of the ventricle

Question 14

What are the management options for obstructive HCM?

Answer 14

Question 15

What are the management options for non-obstructive HCM?

Answer 15

LVEF - left ventricle ejection fraction
In HCM, only left side is relevant

Question 16

What is restrictive cardiomyopathy (RCM)?

Answer 16

Walls of the ventricles become stiff but not necessarily thickened, leading to impaired ventricular filling
Less-well defined - need evidence of a restrictive ventricular filling pattern

Question 17

What are the managements options for RCM?

Answer 17

Heart failure medications - ACE inhibitors, ARBs, diuretics, aldosterone inhibitors - attempting to lower BP
Antiarrhythmic therapy
Immunosuppression - steroids
Pacemaker
Cardiac transplantation