Cardiomyopathies

Question 1

What is a cardiomyopathy and the 4 main types?

Answer 1

• Heart muscle disease
• Dilated
• Hypertrophic
• Restricitve
• Arrythmogenic RV cardiomyopathy

Question 2

Describe dilated cardiomyopathy

Answer 2

• Progessive dilation leading to contractile dysfunction
• Heart enlarged, heavy, flabby (dilated chambers)
• Myocyte hypertrophy with fibrosis
• Causes: genetic (autosomal dominant, cytoskeletal protein gene mutation), alcohol, SLE, Scleroderma, thiamine deficiency, acromegaly, diabetes
• Age 20-50
• Slow progressive signs
• SoB, fatigue, poor exertional capacity
• Treat with transplant of ventricular assist
• 5yr survival due to arrhythmia, CCF, embolism

Question 3

Describe hypertrophic cardiomyopathy

Answer 3

• Myocardial hypertrophy (stiff LV)
• Diastolic function with preserved systolic function
• Thick-walled, heavy & hyper-contracting
• Main causes of unexplained LVH
• 100% genetic (mutations sarcomeric proteins)
• Dec stroke vol due to impaired diastolic filling by reduced chamber size
• Exertional dyspnoea
• V outflow obstruction
• Ant mitral leaflet moves toward V septum during systole

Question 4

What are complications and treatment of hypertrophic cardiomyopathy?

Answer 4

• C: AF, mural thrombus= embolization/stroke, cardiac failure, V arrhythmias, sudden death
• T: β-adrenergic blockers to dec HR & contractility, reduction of mass of the septum

Question 5

Describe restrictive cardiomyopathies

Answer 5

• Primary dec in V compliance so imparied V filling during diastole
• Idiopathic/secondary cause fibrosis, amyloidosis, sarcoidosis, metastatic tumours or deposition of metabolites
• Ventricles normal size
• Myocardium is firm & noncompliant

Question 6

Describe arrythmogenic right ventricular cardiomyopathy

Answer 6

• Genetic
• RV dilation/myocardial thinning
• Fibrofatty replacement of RV
• Disorder of cell-cell desmosomes
• Exercise leads to cell detachment and death
• Silent, syncope, chest pain, palpitations
• Sudden cardiac death