Cardiomyopathy Flashcards
what is cardiomyopathy?
heart muscle disorder without coronary artery disease, hypertension, valvular or congenital heart diseases
prognosis
varying prognoses
can be asymptomatic to severe life-limiting and life threatening
some are associated with sudden cardiac death
types
dilated cardiomyopathy
hypertrophic cardiomyopathy
restrictive cardiomyopathy
epidemiology
can occur at younger age
suspect in any patient presenting with heart failure
hypertrophic cardiomyopathy is the most common cause of unexpected death in childhood
often genetic link
causes
primary = idiopathic secondary = has a cause
secondary causes
connective tissue disorders endocrine disorders drugs infection nutrition genetics
connective tissue disorders that cause cardiomyopathy
sarcoidosis
SLE
endocrine disorders that cause cardiomyopathy
diabetes
thyroid disease
acromegaly
drugs that cause cardiomyopathy
chemotherapeutic agents
cocaine
alcohol
nutrition causes of cardiomyopathy
obesity
vitamin B1 deficiency
calcium deficiency
magnesium deficiency
genetic causes of cardiomyopathy
duchenne muscular dystrophy
clinical divisions of cardiomyopathy
dilated
hypertrophic
restrictive
arrhythmogenic right ventricular
what is dilated cardiomyopathy?
most common type of cardiomyopathy enlarged ventricular normal wall thickness normal systolic function affects left or both ventricles most common indication for heart transplant
epidemiology of dilated cardiomyopathy
2/10,000
often in genetically susceptible individuals
typically presents in 20-60 year olds
more common in men and africans
causes of dilated cardiomyopathy
ischaemic heart disease alcohol cocaine use thyroid disorder valvular disease genetic causes idiopathic infection autoimmune disorders connective tissue disorders granulomatous disorders drugs peripartum - poor prognosis
infective causes of cardiomyopathy
bacterial
HIV
viral - coxsackie or viral myocarditis
pathophysiology of dilated cardiomyopathy
damage to myocardium
some myocardial cells undergo necrosis
chronic fibrosis
remaining myocardial tissue dilates and hypertrophies to compensate for necrosis and fibrosis
what can occur as a result of hypertrophy?
mitral or tricuspid regurgitation
atrial fibrillation - and other arrhythmias
AV node block as a result of atrial dilatation
thrombus formation in large dilated chambers
onset
gradual except when acute myocarditis is the cause
presentation of dilated cardiomyopathy
heart failure: dyspnoea - exertional fatigue peripheral oedema raised JVP - if RV involved loud 3rd and 4th heart sounds arrhythmia thromboembolism - PE/stroke acute myocarditis
what investigations need to be done for dilated cardiomyopathy?
ECG CXR echocardiogram coronary angiogram cardiac muscle biopsy
ECG changes dilated cardiomyopathy
sinus tachycardia
T wave inversion and Q waves - even in absence of previous MI
ST depression
left BBB
CXR dilated cardiomyopathy
enlarged heart
heart failure
pleural effusion
Echo dilated cardiomyopathy
dilated chambers
hypokinetic chambers
used to rule out primary valve disorders
can detect a mural thrombus
coronary angiogram dilated cardiomyopathy
may be considered when there is doubt over diagnosis, potentially ischaemic heart disease or ischaemic heart disease is the cause
cardiac muscle biopsy dilated cardiomyopathy
rarely performed
considered if there a specific cause is suspected such as myocarditis, amyloidosis or sarcoidosis
management of dilated cardiomyopathy
treat reversible causes prophylactic anticoagulation treat arrhythmias consider pacemaker for AVN block treat like heart failure consider implantable cardioverter defibrillator for patients at high risk of arrhythmia consider heart transplant
treating potential reversible causes of dilated cardiomyopathy
toxoplasmosis
haemochromatosis
thyrotoxicosis
prophylactic anticoagulation for dilated cardiomyopathy
warfarin
DOACs
when to consider heart transplant for dilated cardiomyopathy?
younger patients - <60
70% 5-year survival
prognosis of dilated cardiomyopathy
poor
progression results in worsening heart failure
70% mortality in 5 years
sudden death due to thrombus formation or sudden arrhythmia
what worsens dilated cardiomyopathy prognosis?
ventricular wall is thin
ventricles are markedly dilated
what improves dilated cardiomyopathy prognosis?
ventricular wall maintains normal thickness
less dilated
what is hypertrophic cardiomyopathy?
autosomal dominant genetic disorder
causes diastolic dysfunction with or without outflow obstruction
common cause of sudden death in young athletes
what does hypertrophic cardiomyopathy cause?
hypertrophy of left ventricle causing left ventricular outflow obstruction, mitral valve problems, myocardial ischaemia and risk of tachyarrhythmias
epidemiology of hypertrophic cardiomyopathy
most common genetic cardiac disease 1/500 more common in men and black people obstructive = 25% of cases most common cause of sudden cardiac death in young people
age of presentation of hypertrophic cardiomyopathy
between 20-40
what causes hypertrophic cardiomyopathy?
mutation in any 1 or more of 12 genes that code for cardiac proteins
most significant = troponin T mutations, most likely to cause sudden cardiac death
inheritance of hypertrophic cardiomyopathy
autosomal dominant inheritance
variable penetrance and expressivity
pathophysiology of hypertrophic cardiomyopathy
genetic defects in genes coding for cardiac proteins causing disorganised cardiac matrix and left ventricular hypertrophy
hypertrophy can occur in any part of the left ventricle
most commonly affects anterior ventricular septum
which proteins are affected in hypertrophic cardiomyopathy?
beta-myosin heavy chain
troponin
alpha-tropomyosin
presentation of hypertrophic cardiomyopathy
mostly asymptomatic symptoms: dyspnoea - can be initiated by alcohol chest pain syncope on exercise palpitations sudden death family history
syncope in hypertrophic cardiomyopathy
can be initiated by alcohol
can be seemingly unexplained
sudden death from hypertrophic cardiomyopathy
can be due to arrhythmia or due to outflow tract obstruction
unexplained syncope is a risk factor for sudden death
examination for hypertrophic cardiomyopathy
can be normal or abnormal
abnormal examination findings for hypertrophic cardiomyopathy
forceful apex beat
late ejection systolic murmur exacerbated by valsalva manoeuvre and reduced by squatting
prominent JVP
abnormal blood pressure response to exercise - may fall or rise very little
atrial fibrillation - occurs in 20%
what should happen to BP on exercise?
rise by 20-25mmHg
investigations for hypertrophic cardiomyopathy
ECG Echo CXR Cardiac MRI myocardial biopsy cardiac catheterisation
ECG changes in hypertrophic cardiomyopathy
non-specific ST segment changes T wave inversion signs of left ventricular hypertrophy atrial fibrillation
Echo in hypertrophic cardiomyopathy
standard diagnostic test asymmetric septal hypertrophy >15mm ratio of septal wall to posterior wall >1.4:1 non-dilated left ventricular cavity normal systolic function absence of valvular disease
CXR in hypertrophic cardiomyopathy
often normal
heart size may be normal or enlarged
left atrial enlargement seen in mitral regurgitation
cardiac MRI in hypertrophic cardiomyopathy
assessing segmental hypertrophy
can assess systolic and diastolic dysfunction
myocardial biopsy for hypertrophic cardiomyopathy
used to rule out other conditions
cardiac catheterisation for hypertrophic cardiomyopathy
assesses the degree of outflow obstruction and other structural abnormalities
aims of management for hypertrophic cardiomyopathy
reduce symptoms
reduce progression of disease
management of hypertrophic cardiomyopathy
control arrhythmias
anticoagulation for AF
reduce outflow tract obstruction gradient and improve diastolic function
disopyramide used in severe cases
implantable cardioverter defibrillator for those at risk of sudden death
avoid competitive sports and strenuous exercise
surgical myectomy
heart transplatn for severe heart failure
controlling arrhythmias in hypertrophic cardiomyopathy
anti-arrhythmic drugs
ablation therapy
how to reduce outflow tract obstruction gradient and improve diastolic function
beta blockers
verapamil
reduce cardiac contractility and dilate hypertrophied left ventricle, reduce outflow tract obstruction and improve diastolic function
improve physical function of heart but do not treat arrhythmias
disopyramide
negative inotrope
what should we be wary of in hypertrophic cardiomyopathy management?
drugs that reduce preload, as it decreases the chamber size and can exacerbate symptoms ACE inhibitors ARBs nitrites diuretics
surgical myectomy in hypertrophic cardiomyopathy
patients with symptoms resistant to medical management can be managed with resection of the hypertrophied muscle to reduce outflow tract obstruction
mortality risk if hypertrophic cardiomyopathy
annual = 1-3%
higher risk if younger age at presentation
sudden death is most common cause of death
typically sudden death occurs in young patients with few or no symptoms
risk factors for sudden death in hypertrophic cardiomyopathy
unexplained syncopal events episode of ventricular fibrillation or ventricular tachycardia abnormal BP response to exercise family history of sudden cardiac death under 30
how to prevent sudden death in hypertrophic cardiomyopathy
intra-cardiac devices
when to use ICDs in hypertrophic cardiomyopathy?
secondary prevention in any patient who has had a cardiac arrest or previous episode of sustained VT
good prognosis for hypertrophic cardiomyopathy
patients with LVH wall thickness of <20mm and no other risk factors/ low risk have a similar life expectancy to general population
risk of infective endocarditis
low
no need for antibiotic prophylaxis
what is restrictive cardiomyopathy?
reduced compliance of ventricular walls during diastolic filling
most commonly affects LV but can affect both
how common is restrictive cardiomyopathy?
least common of the cardiomyopathies
types of restrictive cardiomyopathy
- infiltration of myocardium by an invasive substance such as amyloid plaques, sarcoidosis or iron in haemochromatosis
- fibrotic myocardium - no external invasive substance
what can restrictive cardiomyopathy cause?
high diastolic filling pressures
leads to pulmonary hypertension
associated with mural thrombi
epidemiology of restrictive cardiomyopathy
most patients are elderly
equal affect on genders
not inherited
more prevalent in tropical regions
causes of restrictive cardiomyopathy
no underlying cause lofflers syndrome amyloidosis most common in western world sarcoidosis haemochromatosis
lofflers syndrome
tropical disease
starts with arteritis which spreads to cause thrombus formation of the endocardium and valves
leads to fibrosis
presentation of restrictive cardiomyopathy
heart failure signs normal/enlarged heart features of right ventricular failure similar presentation to constrictive pericarditis AF in 75% of patients other arrhythmias - AVN block etc.
signs of heart failure associated with restrictive cardiomyopathy
dyspnoea - exertional orthopnoea fatigue pulmonary oedema loud 3rd heart sound
features of right ventricular failure associated with restrictive cardiomyopathy
raised JVP
hepatomegaly
oedema
ascites
investigations for restrictive cardiomyopathy
ECG
CXR
echo
ECG changes in restrictive cardiomyopathy
non-specific T wave and ST changes
pathological Q waves in absence of previous MI
Left ventricular hypertrophy
CXR changes in restrictive cardiomyopathy
heart size is often normal or small
may be enlarged in late stage amyloidosis or haemochromatosis
Echo changes in restrictive cardiomyopathy
normal systolic function
dilated atria
myocardial hypertrophy - increased wall thickness
can help differentiate from restrictive pericarditis
restrictive pericarditis echo
thickened pericardium
treatment aim for restrictive cardiomyopathy
treat underlying cause
early treatment for major underlying causes may reduce disease progression
no specific cardiac medical treatments
some cases suitable for endocardial resection
heart transplant
prognosis of restrictive cardiomyopathy
poor
similar to dilated cardiomyopathy
30% 5 year survival
no effective treatments for most patients that alter the cause of disease
cautions in restrictive cardiomyopathy
diuretics
digoxin
nitrites
why is caution taken with diuretics in restrictive cardiomyopathy?
reduce preload
stiff ventricles rely on preload for filling
why is caution taken with digoxin in restrictive cardiomyopathy?
amyloidosis patients have extreme digoxin sensitivity and can become easily toxic
why is caution taken with nitrites in restrictive cardiomyopathy?
can reduce afterload and cause dangerous hypotension
differential diagnoses for cardiomyopathy
ischaemic heart disease valvular heart disease - mitral and aortic valves athletes pericarditis pulmonary stenosis VSD
type of dysfunction in dilated cardiomyopathy
systolic
type of dysfunction in hypertrophic cardiomyopathy
diastolic potentially plus outflow obstruction
type of dysfunction in restrictive cardiomyopathy
diastolic
