Cardiac disease and sudden death Flashcards
what is the prevalence of LQTS
1 in 2000
what is the prevalence of HCM
1 in 500
what is the prevalence of familial hypercholesterolaemia
1 in 500
familial hypercholesterolaemia has mutations in what
LDLR
APOB
PCSK9
what is the best genetic test for multifactorial heart disease
blood cholesterol
what is sudden cardiac death
non-traumatic, non-violent, unexpected death that results from sudden cardiac arrest within 6 hours of previously witnessed normal health
bilateral diagonal earlobe creases and arcus senilis are signs of what
hyperlipidaemia
how does fat appear under the microscope
clear
blue bag when chest is open implies what
pericardium filled with blood
channelopathies are related to an imbalance in what
ion current
what is LQTS
inherited cardiac condition associated with delayed repolarisation of the ventricles
what can LQTS lead to
polymorphic VT (torsades de pointes)
what causes LQTS to go to TdP
adrenergic stimulation
what causes LQTS
defects in the alpha subunit of the slow delayed rectifier potassium channel
what is the inheritance of LQTS
AD or AR
AD LQTS is associated with _______
name 3 of these types
extracardiac features
- Anderson-Tawil syndrome
- Timothy syndrome
- Romano Ward
AR LQTS is associated with ______
name this type
deafness
- Jervell and Lange-Neillson syndrome
what score is used to determine likelihood of having it
Schwartz score
what risk management strategies can someone with LQTS take
avoid prescription of drugs which prolong QT interval
avoid sudden surges of exercise (LQTS1)
avoid loud noise e.g. alarm clock (LQTS2)
avoid becoming unwell
name some drugs that prolong QT and so should be avoided
- erythromycin / clarithromycin
- amiodarone, sotalol, class 1a antiarrhythmic drugs
- tricyclic antidepressants, selective serotonin reuptake inhibitors (especially citalopram)
how is LQTS treated
avoid risks beta blockers (although sotalol may worsen) ICD in severe
brugada syndrome is a problem with
sodium channels
what is the inheritance of brugada syndrome
AD
brugada syndrome is more common in men/women
men
what arrhythmias are seen in brugada syndrome
AF is common
risk of VF/VT
what gene mutations are assoc with brugada syndrome
SCN5A (cardiac sodium channel)
CACN1AC (cardiac calcium channel)
brugada syndrome ECG changes may only be seen with provocative testing with
flecainide or ajmaline
what are some triggers for VF in brugada syndrome
rest or sleep
fever
excess alcohol or large meals
the genotype and family history doesnt influence prognosis. what does this mean
family member dying of it doesnt make it more likely than another family member will die from it
what are some risk management strategies with brugada syndrome
avoid drugs that might increase ST elevation
early paracetamol in fever
avoid excess alcohol or food
what is the management of brugada syndrome
ICD
what is a condition that is very rare with a very high risk of arrhythmia and people with it usually die in early childhood
short QT syndrome
short QT syndrome is due to mutation in what channels
K+
what is CPVT
catecholaminergic polymorphic ventricular tachycardia
- adrenergic induced bidirectional and polymorphic VTs and SVTs
what is the inheritance of CPVT
AD
CPVT is a problem with what
ranitidine receptor
what arrhythmias are seen in CPVT
polymorphic VT
SVTs
what is the prevalence of CPVT
1 in 10,000
what would an ECG/echo of CPVT look like
normal
what is the treatment of CPVT
high dose BB and ICD
sometimes treat with flecainide
what triggers the arrhythmias in CPVT
emotional stress, physical activity
people with CPVT should avoid
competitive sports
what causes WPW
accessory pathway from atria to ventricles bypassing the AV node leading to atrioventricular re-entry tachycardia (AVRT)
what can AF progress to in WPW and why
VF - no slowing down of conduction through accessory pathway
how is WPW diagnosed
on treadmill to see if they can still conduct at maximum HR
how does HCM present
HF or sudden death
when should you consider an ICD in HCM
risk of sudden death > 4%
people with HCM should avoid
competitive sport
where does the problem lie with HCM
output difficulty due to huge mass of muscle
the mutation is in what genes in HCM
sarcomeric
DCM is more common in males/females
males
what is the inheritance of HCM
AD
what is the inheritance of DCM
AD
what happens in DCM
slowly over time the heart muscles dilate and scar leading to rhythm problem
what is ARVC
arrhythmogenic right ventricular cardiomyopathy
- fibro-fatty replacement of cardio myocytes
what is the inheritance of ARVC
AD but can be AR
is ARVC easy or difficult to treat
difficult
how is ARVC treated
ICD and BB (sotalol)
people with ARVC should avoid
competitive sports
what kind of screening is important with inherited cardiac conditions
familial (cascade) screening
where do the 2 leads of an ICD go
one to right ventricle
one to right atrium
what is the risk of death when taking out leads of an ICD
1 in 100
what are some complications of an ICD
endocarditis, perforation, haemothorax, pneumothorax, embolism, leads can break or move or deliver shock when not required
what is an after depolarisation
abnormal depolarisation of cardiac myocytes
EADs cause
TdP
what is automaticity
SA node fires generating a heart beat without any external stimulus
