long QT syndrome Flashcards
1
Q
what kind of disorder
A
monogenic
2
Q
what mutations
A
cardiac potassium and sodium-channel genes
3
Q
how many subtypes
A
13
4
Q
what are 3 major subtypes
A
- KCNQ1 gene (LQT1)
- SCN5A (LQT2)
- KCNH2 (LQT3)
5
Q
what is KCNQ1 provoked by
A
exercise particularly swimming
6
Q
what is KCNH2 gene provoked by
A
emotion and acoustic stimuli
7
Q
what is SCN5A occur
A
during sleep
8
Q
what is is QT prolongation provoked by
A
bradycardia
9
Q
symptoms
A
- syncope
- palpitations
10
Q
can they terminate spontaneously
A
yes
but can result in sudden death
11
Q
what is torsades de pointes like on ECG
A
rapid, irregular sharp complexes
12
Q
treatment for acute
A
- causative drugs stopped
- heart rate maintained
- magnesium sulphate (given for 10-15 minutes)
- IV isoprenaline
13
Q
treatment for long term
A
- beta-blockade
- pacemaker therapy
14
Q
what do LQT1 respond to
A
beta-blockade
15
Q
what do LQT3 respond to
A
sodium channel blckers
