cardiac conditions that cause sudden death Flashcards
what is considered a long QT interval usually
>450ms
what happens in long QT syndrome
the ventricular repolarizationis prolonged - long QT interval
romano ward syndrome
autosomal dominant cuase of long QT syndrome - causes isolated long QT
JLN syndrome
autosomal recessive cause of congenital long QT - associated with congenital deafness
why does hypokalaemia cause acquired long QT
K leaving the cell si responsible for stages 2 3 and 4 of the AP
if there is less K, prolongs the plateau phase
what 2 other electrolyte abnormalities cause acquried long QT
hypoMg
hypoCa
which ABx cause long QT
macrolides eg azithromycin
what other drugs cause long QT
antidepressants, TCA and citalopram
antipsychotics
which class of anti arrhythmic drugs prolonged the plateau phase of the cardiac AP
3 - amiodarone and sotalol
what do the LGT genes encode
cardiac potassium and sodium channels
what is the genetics cause of long qt
heterogenous - caused by lots of different genes
each different gene causes a disease with a different phenotype
what are the particular provocations for LGT 1 2 and 3
1 - strenuous exericse, especially swimming
2 - emotion and loud noises
3 - rest or sleep
what can long at lead to and what are the symptoms
torsade de pointes - a polymorphic ventricular tachycardia
syncope and palpitations
what is the danger of TdP
it can degenerate into ventricular fibrillation
can terminate spontaneously
what is assoicated with increased risk in long qt syndrome
the length of the qt interval
what treatment is advised for congenital long qt syndrome
- avoid triggers
- beta blockers (not sotalol)
- permanent pacing
- ICD
who is eligible for an ICD with congenital long qt
those resuscitated from cardiac arrest or those with syncope despite beta blocker treatment
genes encoding which channels are mutated in short QT syndrome
K channels
short QT syndrome presentation
usually seen in young children adn they often dont survive, it is a cause of SIDS
assoicated with AF, ventricular arhythmias and suden death
management of short QT syndrome
ICD
what is the classical ECG of brugada syndrome
ST elevation, inverted T wave, RBBB in V1-3
does someone with brugada syndrome have ecg changes all the time?
no, may be intermittent and change over time
often seen with fever
what drugs can be used to provoke ecg changes in brugada syndrome
class 1 anti arrhythmics - flecainide or ajmoline
what are some triggers for VF in brugada syndrome
rest, sleep, fever, aalcohol, large meals
