Sudden Cardiac Death - Conditions Flashcards
a patient with a cardiac caused sudden death tend to die between _ hours of previous wellbeing
6
name cardiac causes of sudden death
inherited arrhythmia syndrome
inherited cardiomyopathy
inherited multisystem disease with CVS involvement eg myotonic dystrophy
arrhythmia syndromes can also be called…
channelopathies
give examples of inherited channelopathies
congenital long QT syndrome brugada syndrome catecholaminergic polymorphic VT short QT syndrome familial AF or WPW
give examples of inherited cardiomyopathies
hypertrophic cardiomyopathies
screening is normal in what cardiomyopathies?
dilated
hypertrophic
ARVC (arrhythmogenic right ventricular cardiomyopathy)
what process keeps the SA node firing
automaticity
2 main reasons for arrhythmias
problems with automaticity
re-entry
what are after depolarisations
abnormal depolarisations of cardiac myocytes that interrupt phases 2, 3 and 4 of the cardiac AP
what do after depolarisations cause in the heart?
triggered automaticity
when do early repolarisations occur?
during phases 2 and 4 of the cardiac AP
what do early repolarisations cause?
torsades de pointes
when in the cardiac AP do delayed depolarisations occur?
phase 4
what do delayed depolarisations cause?
bidirectional VT
inheritance pattern of cardiac conditions?
AD
inheritance pattern of cardiac conditions?
AD
commonest inherited cardiac cause of sudden death?
long QT
how many people are carriers of long QT gene
1 in 2000
what cardiac changes are seen in long qt
torsades de pointes (polymorphic VT)
trigger for the cardiac changes seen in long qt?
adrenergic stimulation eg by excitement, exercise
what is romano-ward syndrome? what is its inheritance?
most common form of long qt
AD
what long qt syndrome is associated with deafness? is it AD or AR inheritance?
jervell and lange-nielsen syndrome
AR
pathophysiology behind long qt
reduced ionic current = prolonged cardiac repol = wt interval prolongation
how is long qt diagnosed?
QT >480ms in repeated ECGs
if your long qt risk score is >3
presence of LQTS mutation
symptoms of long qt
syncope
stress
potentially Hx of deafness (JALNS)
what drugs should be avoided in long qt?
clarithromycin
azithromycin
imipramine
amitryptiline
LQTS1 main prophylactic advice?
avoid strenuous exercise
LQTS2 main prophylactic advice?
avoid loud noises
pathophysiology of short qt
K+ channels
how long is the qt interval in short qt
<300ms
who gets short qt
young children
youre at increased risk of what arrhythmias
polymorphic VT (TDP) VF
what cardiac condition do people with brugada syndrome get?
AF
what are the ECG findings in brugada syndrome
ST elevation and RBBB in V1-3
inheritance of brugada syndrome? who gets it?
AD
adult males
triggers for VF in brugada syndrome
excess alcohol
large meals
rest
fever
Tx brugada syndrome
avoid triggers
avoid Na channel blockers/anti-arrhythmias
go into hospital if fever
ICD if severe
what is CPVT? what triggers it?
adrenergic induced TDP, SVTs that are triggered by stress and exercise
ECG and ECHO are what in CPVT?
normal
Tx CPVT?
sedate
defibrillate
avoid triggers
b blockers long term (blocks adrenergic stimulation)
+/- ICD
ECG features of WPW syndrome
short PR interval
delta waves
venticular preexcitation
most common arrhythmia in WPW syndrome
AVRT
pathophysiology of WPW syndrome
no conduction delay between atria and ventricles because of an accessory pathway
Tx WPW
leave it if the accessory pathway does not conduct quickly
cardiac ablation if it does
commonest cardiomyopathy?
hypertrophic
mutation is where in hypertrophic cardiomyopathy
sarcomeric genes
how many patients will die per year of HOCM?
1%
ECG changes that suggest hypertrophy?
positive deflection in V5
negative deflection in V2
different presentations of HOCM
sudden death
HF (from progressive ischaemia)
end stage HF
AF (thick muscles inc diastolic pressure)
Tx HOCM
ICD if previous cardiac arrest or sustained VT OR if high risk eg 1st degree FH, thick LV wall, recent syncope
if none, leave it esp if risk is under 4%
who gets dilated cardiomyopathy
adulthood-elderly
men>women
pathophysiology of DCM
sarcomere protein problem (20% is genetic related)
what does DCM progress to?
HF
pathophysiology of ARVC?
fibrofatty replacement of myocytes allowing more space for reentry (VT most common)
how common is LV invovlement in ARVC?
50%
features of ARVC on ECG?
QRS prolongation
Tx ARVC
avoid competitive sports
- beta blockers
- ICD if severe
diagnosis of inherited cardiac conditions
clinical and genetic testing
family screening
what does defibrillation do?
delivers high energy causing cardiac myocytes to depolarise, resets all cardiac myocytes to restore electrical signal
what does ICD mean?
implantable cardioverter defibrillator
complications of ICDs?
leads can cause infection eg endocarditis
can cuse pneumo/haemothorax
thromboembolic eg PE
lead fractures (can slit the SVC on removal)
how long do ICD leads last?
20 yrs
