cardiomyopathy Flashcards
what is cardiomyopathy?
structural and functional disorder of ventricular myocardium (heart muscles) not caused by another cardiac disease.
name 6 subtypes of cardiomyopathy
hypertrophic
dilated
restrictive
arrhytmogenic right ventricular (ARVC)
takostubo
peripartum
what happens in hypertrophic cardiomyopathy (HCM)?
abormal growth of myocardium specifically left ventricle (>15mm) and atrial septum. NOT secondary to diseases which cause LVH eg htn, aortic stenosis
what happens in HCOM?
some patients with hypertrophic cardiomyopathy develop left ventricular outflow tract obstruction (LVOTO) due to septum growing assymetrically and obstructing blood flow through aortic valve
what are some potential signs of LVOTO?
ejection systolic murmur
can sometimes cause mitral regurgitation
what are the genetics behind HCM?
60% of cases are due to a single autosomal dominant inherited mutation.
some can be spontaneous non inherited mutations
if someone has a strong family history of HCM/sudden cardiac death but no genetic causes were found in genetic tests what needs to happen?
family members have regular cardiac screening with ECGs and echos
what happens in dilated cardiomyopathy?
dilated and thin walls, less contractility
what is the most common consequence of dilated cardiomyopathy?
heart failure
what are the causes of dilated cardiomyopathy?
usually idiopathic
can be caused by single gene mutations, usually autosomal dominant genetic inheritance
what are the risk factors for dilated cardiomyopathy?
FH
alcohol
chemotherapy
viral myocarditis
autoimmune disease
pregnancy
what happens in restrictive cardiomyopathy?
stiff ventricle walls leading to less ventricular filling. atria can also become enlarged as a result of this extra pressure.
what are the causes of restrictive cardiomyopathy?
usually due to systemic disease which leads to abnormal protein infiltration or scarring of ventricle walls eg amyloidosis, sarcoidosis, haemachromatosis
what happens in arrhythmogenic right ventricular cardiomyopathy (ARVC)?
replacement of normal myocardium with fibro-fatty tissue. abnormal tissue is high risk of conducting electrical signals poorly and patients are at risk of developing life threatening arrhythmias.
what can you do in ARVC to reduce the number of VTs?
radio-ablation -use heat on area of heart causing abnormal rhythm to break abnormal circuits and destroy areas of heart muscle which are triggering arrythmias
what are the differences between primary and secondary cardiomyopathies?
primary =primary disease of heart muscle itself eg HCM, myocarditis
secondary=develops due to secondary condition eg amyloidosis, sarcoidosis, haemachromatosis , fabry’s disease
what is fabry’s disease?
genetic disorder that means you don’t have an enzyme to break down some lipids so some lipids build up in different organs in the body.
what are the red flags for cardiomyopathy?
sx of poor cardiac output esp exercise induced: dyspnoea, angina, syncope, lightheadedness
palpitations
FH of sudden cardiac death, unexplained wierd heart things
what are some signs of cardiomyopathy?
forceful apex beat -in hypertrophic
S4 heart sound (atrial gallop) -caused by atria contracting forcefully to try and pump blood into thickened ventricles-found in hypertrophic and restrictive.
double impulse
ESif HOCM -made worse by valsalva manouvre which increases preload
what can be found on an ECG in HCM?
evidence of LVH
deep narrow Q waves
what is the best initial imaging test for cardiomypathy?
echo
what are some beyond tests that may be needed for cardiomyopathy?
ambulatory ECG
exercise stress testing
cardiac MRI
genetic testing
ventricular biopsy
what can you assess with ambulatory ECG?
arrhythmias
when would you do genetic testing in someone with cardiomyopathy?
someone with HCM and a strong FH of HCM (>1 relative with known disease) or FH of severe disease (unexplained sudden cardiac death)
when would you do a ventricular biopsy in cardiomyopathy?
patients with restrictive CM might rarely need one to see what’s been causing the restrictions.
what is the leading cause of death in young people and how does it happen?
HCM
usually occurs during exertion and has been noted in extreme athletes
most common noted cause =VF
what advice are young people with HCM given?
avoid competitive sports
avoid becoming dehydrated
what are the complicatiosns of cardiomyopathy?
sudden death
heart failure
arrhythmias and AF
clots
why does cardiomyopathy lead to arrhythmias and which types?
abnormal heart structure leads to issues with electrical conduction
AF-1/5 of HCM patients!
non sustained VT
VF
how can you manage arrhythmias caused by cardiomyopathies?
consider anticoag for AF
consider ICDs
consider beta blockers and verapamil
why does cardiomyopathy cause clots?
abnormal movement of the heart
