Cardiomyopathy Flashcards
What does cardiomyopathy mean?
heart muscle disease
a disorder in which heart muscle is structurally and functionally abnormal (in the absence of other heart conditions severe enough to cause the heart muscle abnormality)
Name 4 types of cardiomyopathies and their basic cause
hypertrophic - heart muscle thickens (especially ventricular septum)
dilated (heart muscle stretches and weakens)
arrhythmogenic right ventricular (fat and scar tissue replace muscle in right ventricle)
restrictive (walls of ventricles become stiff)
What is the commonest cause of sudden cardiac death (SCD) in <35 years?
hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy inheritance
autosomal dominant
autosomal dominant mutations in genes that code for components of the sarcomere
What age does hypertrophic cardiomyopathy present?
any age
Describe myocytes in hypertrophic cardiomyopathy
myocytes thickened and in disarray
separated by areas of scar/fibrous tissue
Describe hypertrophic obstructive cardiomyopathy (HOCM)
turbulent blood flow from left ventricle into aorta due to thickened ventricular septum pulls anterior mitral leaflet towards septum, causing an outflow obstruction and mitral regurgitation
HOCM symptoms and reasons for them
syncope (due to ventricular arrhythmias)
sudden death (due to ventricular arrhythmias)
SOB (due to impaired relaxation and therefore increased LVEDP)
chest pain (due to increased myocardial demand)
Hypertrophic cardiomyopathy examination findings
may be normal
double apical impulse
S4
features of systolic outflow obstruction:
- jerky pulse (brisk carotid upstroke which suddenly stops)
- systolic murmur (murmur at left sternal edge, mitral regurgitation)
ECG findings in hypertrophic cardiomyopathy
left ventricular hypertrophy (tall QRS)
repolarisation abnormalities (T wave inversion)
Management of hypertrophic cardiomyopathy
education + reassurance
risk stratification for sudden cardiac death
management of symptoms and complications
family screening
Describe risk stratification and outcomes in hypertrophic cardiomyopathy
prior event (SCD, sustained VT) = highest risk = ICD recommended
> = 1 risk factor (FH SCD, massive LVH, syncope, LV aneurysm, impaired LV function, non-sustained VT, extensive scar on CMR) = intermediate risk = ICD can be considered
no risk factors = lowest risk = ICD not recommended
How can hypertrophic cardiomyopathy be treated?
treat symptoms
Beta blockers (or Verapamil):
- decrease heart rate (increase diastolic filling time)
- decrease force of contraction (decrease myocardial oxygen demand)
obstruction:
- myomectomy if still symptomatic
(remove chunk of thickened septum)
Name 2 hypertrophic cardiomyopathy complications and describe how they can be managed
AF - anticoagulate, rate/rhythm control
heart failure - drugs or myomectomy, refractory HF symptoms should be referred for transplant
Describe family screening in hypertrophic cardiomyopathy
genetic counselling for all patients
50% chance of passing gene onto children
if pathogenic mutation detected then cascade family screening can be offered to first degree relatives
if no clear mutation detected then first degree relatives should have regular (~5 yearly) follow up with ECG and ECHO
Causes of dilated cardiomyopathy
idiopathic
genetic (familial, neuromuscular - myotonic or muscular dystrophy)
inflammatory: infectious = post-viral, non-infectious = connective tissue disease, peripartum cardiomyopathy, sarcoidosis
toxic (alcohol, chemotherapy)
metabolic (hypothyroidism)
tachycardia induced
What is the management of dilated cardiomyopathy the same as?
treatment for HFrEF
Describe arrhythmogenic cardiomyopathy
an inherited heart muscle disease characterised by progressive replacement of the myocardium by fibrofatty tissue
predisposes to ventricular arrhythmias and impaired contraction
Which part of the heart does arrhythmogenic cardiomyopathy most commonly affect?
right ventricle
When does arrhythmogenic cardiomyopathy present?
young-middle age
Arrhythmogenic cardiomyopathy presentation
asymptomatic
palpitations
syncope
sudden death
What is arrhythmogenic cardiomyopathy a disease of?
desmosome (binds muscles together)
fibrofatty tissue prevents desmosomes from correctly binding myocytes
Arrhythmogenic cardiomyopathy ECG changes
T wave inversion
localised prolongation of QRS interval in right precordial leads (V1-V3)
What is the typical arrhythmia in arrhythmogenic cardiomyopathy?
LBBB VT
(in contrast VT coming from LV has a RBBB pattern)
Arrhythmogenic right ventricular cardiomyopathy clinical phases
concealed phase (patient asymptomatic but still SCD risk)
electrical phase (symptomatic ventricular arrhythmias)
advanced phase (right ventricular or biventricular failure)
Management of ARVC
risk stratification for sudden death (defibrillators for highest risk)
improve symptoms and quality of life:
- ventricular arrhythmias = beta-blockers, antiarrhythmic drugs, catheter ablation
- heart failure = diuretics, HF medications, heart transplant
prevent disease progression (exercise restriction - vigorous exercise associated with accelerated disease progression and increased risk of ventricular arrhythmias)
cascade screening of family members
What causes restrictive cardiomyopathy?
due to myocardial fibrosis or infiltration (usually amyloid)
poor prognosis
Signs and symptoms of restrictive cardiomyopathy and the reasons why they are present
jugular venous distention, hepatomegaly, ascites and peripheral oedema - due to rigid myocardium causing increased ventricular pressure, causing venous congestion
weakness and fatigue - due to rigid myocardium causing reduced ventricular filling causing decreased cardiac output
