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CARDIOLOGY > CARDIOMYOPATHIES > Flashcards

CARDIOMYOPATHIES Flashcards

1
Q

What is cardiomyopathy?

A

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

(a disease of heart muscle that cannot otherwise be explained by common cardiovascular diseases or congenital heart disease)

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2
Q

What are the different types of cardiomyopathies?

A

Hypertrophic cardiomyopathy
Dilated cardiomyopathy
Restrictive cardiomyopathy
Arrhythmogenic cardiomyopathy
Unclassified cardiomyopathies

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3
Q

How is each subtype of cardiomyopathy further classified?

A

Familial causes - develops due to a genetic variant
Non-familial causes - develops due to a clear acquired cause

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4
Q

What are some secondary causes of cardiomyopathy?

A

Drugs (e.g. chemotherapy, hydroxychloroquine, cocaine use)
Infections (e.g. Coxsackie virus, Brucellosis, Lyme disease)
Systemic diseases (e.g. amyloidosis, sarcoidosis)
Nutritional deficiencies (e.g. beriberi) and obesity
Radiation
Malignancy
Alcohol
Endocrine - diabetes, thyrotoxicosis, acromegaly
Connective tissue disorders
Genetic causes e.g. duchennes

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5
Q

Outline the pathology behind inherited causes of cardiomyopathy?

A

The abnormal gene often encodes important structural cardiac proteins such as sarcomere proteins or intercalated disc proteins. In these cases, cardiomyopathy often presents as the lone abnormality. These commonly have an autosomal dominant inheritance. Examples include beta-myosin heavy chain, troponin, or desmoplakin mutations.

In other cases, the abnormal gene may cause a widespread genetic disease involving multiple organs of which cardiomyopathy is one component of the disease spectrum. Examples include Myotonic dystrophy, Fabry disease, or Glycogen storage disease.

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6
Q

How is cardiomyopathy diagnosed?

A

Echocardiography - helps define morphological and functional features of each cardiomyopathy phenotype as well as exclude other causes of heart muscle disease
Cardiac MRI/CT can provide more detailed information to better classify suspect cardiomyopathy

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7
Q

What is peripartum cardiomyopathy?

A

A type of dilated cardiomyaopthy
rare but serious that can lead to HF and even death
Typical develops between last month of pregnancy and 5 months post-partum
More common in older women, greater parity and multiple gestations. Women who have hypertension history, preeclampsia or gestational diabetes may be at higehr risk

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8
Q

What is Takotsubo cardiomyopathy?

A

‘Stress’-induced cardiomyopathy e.g. patient just found out family member dies then develops chest pain and features of heart failure
Transient, apical ballooning of the myocardium

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9
Q

What is hypertrophic cardiomyopathy?

A

Increased ventricular wall thickness or mass not caused by pathologic loading conditions (e.g. hypertension)

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10
Q

Whats the aetiology of hypertrophic cardiomyopathy?

A

Most commonly due to an abnormal gene that encodes one of the sarcomere proteins needed for myocardial contraction
The most common mutation in the gene that encodes the beta myosin heavy chain protein or myosin-binding protein C
inheritance is usually autosomal dominant

Can also be idiopathic

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11
Q

Outline the pathophysiology of hypertrophic cardiomyopathy

A

Mutation in one of the several myocyte sarcomere genes causing an abnormal increase in the number and size of sarcomeres (concentric hypertrophy), resulting in the thickening of the heart muscle and disarray of cardiac muscle fibers, which can impair the ability of the heart to contract and relax properly. It causes septal hypertrophy particularly on the left ventricle side. This can lead to diastolic dysfunction. thickening of the heart muscle can lead to obstruction of blood flow from the left ventricle to the aorta, known as left ventricular outflow tract obstruction. The thickening of the heart muscle can also affect the function of the mitral valve and cause arrhythmias

Abnormal hypertrophy can have numerous pathological consequences:
- left ventricular outflow obstruction
- mitral regurgitation
- diastolic dysfunction
- systolic dysfunction
- arrhythmias

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12
Q

Why does hypertrophic cardiomyopathy cause left ventricular outflow obstruction?

A

Septal hypertrophy narrows the outflow tract from the left ventricle to the aorta = obstructs blood flow out of the heart
The hypertrophy can cause abnormalities in the mitral valve which can also cause obstruction or create turbulent blood flow

This collectively causes obstruction to blood flow during systole.

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13
Q

Why does hypertrophic cardiomyopathy cause mitral regurgitation?

A

Hypertrophy of heart muscle causes displacement of the mitral valve, systolic anterior motion of the mitral valve and abnormalities in mitral valve leaflets/chordea tendinae

These factors cause the valve to leak

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14
Q

Why does hypertrophic cardiomyopathy cause diastolic dysfunction?

A

Fibrosis and hypertrophy limit the compliance of the ventricle leading to reduced ability to relax and fill during diastole.

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15
Q

Why does hypertrophic cardiomyopathy cause systolic dysfunction?

A

Hypertrophy can disrupt the normal arrangement of muscle fibres making it diffiuclt for the heart to contract effectively = reduction in the left ventricular ejection fraction
Thickened Herat muscle also reduces the size of the left ventricle which can decrease the pre-load

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16
Q

Why does hypertrophic cardiomyopathy cause arrhythmias?

A

Remodelling of heart muscle which can create areas of scar tissue and disrupt the normal electrical pathways of the heart
Hypertrophy of heart can also create areas of ischaemia which can also increase the risk arrhythmias

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17
Q

What are clinical features of hypertrophic cardiomyopathy?

A

Majority asymptomatic
Syncope with exertion
Sudden cardiac death
Heart failure symptoms - Fatigue, SOB, orthopnoea, ankle swelling, chest pain, presyncope, syncope, palpitations
Ejection systolic murmur from left ventricular outflow obstruction
Mid-late systolic murmur - mitral regurgitation
S4

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18
Q

How is hypertrophic cardiomyopathy diagnosed from echo?

A

Increased left ventricular wall thickness ≥15 mm in the absence of any other identifiable cause

Mitral regurgitation
Systolic anterior motion of anterior mitral valve
Asymmetric septal hypertrophy

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19
Q

What ECG changes might you see in hypertrophic cardiomyopathy?

A

Evidence of left ventricular hypertrophy:
Non-specific ST segment abnormalities e.g. ST depression
T wave inversion
Deep/dagger-like Q waves
Signs of left ventricular hypertrophy
AF in 20% of pt
Left axis deviation

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20
Q

How is hypertrophic cardiomyopathy characterised on biopsy?

A

myofibrillar hypertrophy with chaotic and disorganized fashion myocytes and fibrosis

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21
Q

How do you manage hypertrophic obstructive cardiomyopathy?

A

Amiodarone (for arrhythmias. Also anticoagulate if AF)
Beta-blockers or verapamil (for symptoms of HF as they reduce left ventricular outflow tract gradient and diastolic dysfunction)
Implantable Cardioverter defibrillator if at risk for sudden death
Septal/surgical myectomy if unresponsive to medical therapy

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22
Q

What drugs should you avoid in hypertrophic obstructive cardiomyopathy? And why?

A

ACEi, Nitrates and inotropes
They decrease after load which would lead to worsening LV outflow tract obstruction

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23
Q

Whats the most common cause of sudden cardiac death in the young?

A

Hypertrophic obstructive cardiomyopathy

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24
Q

Whats the inheritance pattern of hypertrophic cardiomyopathy?

A

Autosomal dominant
However, half the cases are as a result of sporadic mutations where parents dont carry a disease-causing mutation

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25
Q

Whats the prevalence of hypertrophic cardiomyopathy?

A

1 in 500 adults

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26
Q

What age does hypertrophic cardiomyopathy typically affect?

A

Late childhood and adolescence - especially if there is FHx or child had symptoms
HCM may not be diagnosed until later in life, when symptoms or complications of the condition become apparent.

27
Q

What is dilated cardiomyopathy?

A

dilatation and impaired contraction of one or both ventricles that commonly manifests as heart failure

28
Q

Whats the most common form of cardiomyopathy?

A

Dilated cardiomyopathy - accounts for 90% of cases

29
Q

What can cause dilated cardiomyopathy?

A

Idiopathic
myocarditis: e.g. Coxsackie B, HIV, diphtheria, Chagas disease
ischaemic heart disease
peripartum
hypertension
iatrogenic: e.g. doxorubicin
Chagas’ disease
Nutritional deficiencies e.g. wet beriberi
substance abuse: e.g. alcohol, cocaine
inherited: either a familial genetic predisposition to DCM or a specific syndrome e.g. Duchenne muscular dystrophy
infiltrative e.g. haemochromatosis, sarcoidosis

30
Q

Whats the most common cause of dilated cardiomyopathy?

A

Idiopathic (up to 50%)

31
Q

Whats the pathophysiology of dilated cardiomyopathy?

A

Progressive dilation of chambers of the heart, particularly the left ventricular cavity and eccentric hypertrophy that cases heart walls to thin and lose contractility= leads to progressive systolic dysfunction and reduced ejection fraction

32
Q

What are typical clinical features of dilated cardiomyopathy?

A

Characterised by the development of HF

Breathlessness
Reduced exercise tolerance
Fatigue
Orthopnoa
Paroxsymal nocturnal dyspnoea: severe, sudden shortness of breath, usually at nighttime
Peripheral oedema
Palpitations: due to the development of arrhythmias

Systolic murmur and S3 (due to blood slamming into dilated vertical wall)

33
Q

What might ECG changes might you see with dilated cardiomyopathy?

A

Poor R wave progression

34
Q

What might you see on CXR in dilated cardiomyopathy?

A

Balloon appearance of heart

35
Q

What would you see on an echo in dilated cardiomyopathy?

A

evidence of dilation and impaired contraction of the left ventricle or both ventricles
Thinning of LV wall

36
Q

How do you manage dilated cardiomyopathy?

A

HF treatment - ACEi, beta blockers, diuretics etc

Cardiac transplantation is more likely to be considered due to the young age of onset

37
Q

What is restrictive cardiomyopathy?

A

An uncommon cardiomyopathy due to stiff non-compliant myocardium
characterised by abnormal ventricular filling in non-dilated and non-hypertrophied ventricles

38
Q

What causes restrictive cardiomyopathy?

A

Infiltration disease e.g. amyloidosos (most common!), haemachromatosis or sarcoidosis
Familial non-infiltrative cardiomyopathy - Inheritance of abnormal sarcomere gene
Storage diseases
Radiation and some chemotherapy
Loefflers endocarditis

39
Q

What is Loeffler’s endocarditis?

A

A restrictive cardiomyopathy caused by infiltration of eosinophils. This leads to inflammation, scarring and thickening of the endocardium which can eventually lead to HF

40
Q

Whats the pathophysiology of restrictive cardiomyopathy?

A

Myocardium becomes stiff and less compliant -> ventricles unable to fill fully during diastole -> decreased stroke volume and cardiac output -> increased pressure causing dilated atria = diastolic HF

41
Q

What are clinical features of restrictive cardiomyaopthy?

A

Symptoms of HF
Arrhythmias (up to 75% will have AF)
Sudden cardiac death

42
Q

What does an echo show for restrictive cardiomyopathy?

A

non-dilated, non-thickened ventricles with abnormal ventricular filling, features of diastolic dysfunction and usually atrial enlargement

43
Q

How do you manage restrictive cardiomyopathy?

A

Treatment of RCM should be aimed at the underlying cause whilst optimising patients with heart failure, particularly fluid overload. However, many prognostic medications used in chronic heart failure are ineffective in patients with RCM.

44
Q

How can you differentiate between restrictive cardiomyopathy and constrictive pericarditis?

A

Appear the same on echo
Cardiac MRI

45
Q

What are arrhythmogenic cardiomyopathies?

A

a group of rare disorders that affect the myocardium and are characterised by frequent arrhythmias and ventricular dysfunction.

3 types:
Arrhythmogenic right ventricular cardiomyopathy
Arrhythmogenic left ventricular cardiomyopathy
Dilated cardiomyopathy with arrhythmias

46
Q

What is arrhythmogenic right ventricular cardiomyopathy?

A

a form of inherited cardiovascular disease which may present with syncope or sudden cardiac death. It is generally regarded as the second most common cause of sudden cardiac death in the young after hypertrophic cardiomyopathy.

47
Q

Whats the pathophysiology of arrhythmogenic right ventricular cardiomyopathy?

A

inherited in an autosomal dominant pattern with variable expression
around 50% of patients have a mutation of one of the several genes which encode components of desmosome

the right ventricular myocardium is replaced by fatty and fibrofatty tissue. This fibro-fatty replacement causes the right ventricle to become thinner and weaker which can disrupt the normal structure of the heart and cause progressive right ventricular dystrophy

48
Q

How does arrhythmogenic right ventricular cardiomyopathy present?

A

Palpitations
Syncope
Sudden cardiac death

49
Q

What are ECG changes for arrhythmogenic right ventricular cardiomyopathy?

A

T wave inversion in V1-3
Epsilon wave in abut 50% of cases (terminal notch in QRS)

50
Q

What is seen on echo for arrhythmogenic right ventricular cardiomyopathy?

A

Subtle in early stages but may show enlarge, hypokinetic right ventricle with a thin free wall

51
Q

How is arrhythmogenic ventricular cardiomyopathy diagnosed?

A

ECG
Echocardiogram
Cardiac MRI (may show fibro-fatty changes)

52
Q

How is arrhythmogenic right ventricular cardiomyopathy managed?

A

Prevention of sudden cardiac death with anti-arrhythmias (sotalol) and Catheter ablation to prevent V tach
Implantable cardiac defibrillator

53
Q

What is Naxos disease?

A

A rare genetic disorder characterised by the presence of arrhythmogenic cardiomyopathy and palmoplantar keratoderma and woolly hair

Inherited in an autosomal recessive pattern

54
Q

Whats the pathophysiology of Takotsubo’s cardiomyopathy?

A

Not fully understood
Thought to be caused by release of catecholamines which cause small blood vessels in the heart to constrict, reducing blood flow to the heart muscle
Another theory is that stress hormones may cause direct damage to the heart muscle

55
Q

Why is Takotsubo cardiomyopathy named after an octopus trap?

A

Severe hypokinesis of mid and apical segments of the left ventricle with preservation of activity of basal segments = apical ballooning appearance

56
Q

Who does Takotsubo cardiomyopathy typically affect?

A

Post menopausal women

57
Q

What are the features of Takotsubo cardiomyopathy?

A

chest pain
features of heart failure
ECG: ST-elevation
normal coronary angiogram

58
Q

How do you manage Takotsubo cardiomyopathy?

A

Usually a transient disorder so is managed with supportive therapy

59
Q

What is left ventricular non-compaction cardiomyopathy?

A

A rare form of genetic cardiomyopathy characterised by a spongy appearance of the myocardium in the left ventricle
Thought to be the result of the failure of the myocardium to properly compact during foetal development leading to recesses in the myocardium in the adult heart
Results in impaired heart function

60
Q

What is Friedreich’s ataxia? And why is it associated with cardiomyopathies?

A

A rare, genetic neurodegenerative movement disorder
It is a trinucleotide repeat expansion disorder that can cause death of myocyte and difficulty pumping of blood leading to thickening of ventricles and hypertrophic cardiomyopathy

61
Q

In hypertrophic cardiomyopathy, what can cause a louder systolic murmur?

A

Valasalva manoeuvre, standing up
(reduced preload and afterload = lower ventricular blood volume = allowing for closer proximity of the mitral valve to the hypertrophied septal wall = more turbulent blood flow.)

62
Q

In hypertrophic cardiomyopathy, what can cause a quieter systolic murmur?

A

Hand grip or squatting
(Pre-load increases = increased amount of blood within ventricles = reduces proximity of mitral valve to hypertrophied septal wall = less turbulent blood flow)

63
Q

What arrhythmias is hypertrophic cardiomyopathy associated with?

A

Wolff Parkinson white syndrome
AF

CARDIOLOGY (19 decks)

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