long QT syndrome

Question 1

what is long QT syndrome

Answer 1

prolonged QT interval

Question 2

is long QT syndrome congenital or acquired

Answer 2

can be either

Question 3

what causes acquired long QT syndrome

Answer 3

electrolyte abnormalities
diabetes
acute MI
drugs

Question 4

list the drug triggers of acquired ling QT syndrome

Answer 4

beta blockers
psychotropics
analgesics
anaesthetics

Question 5

describe the triggers for QT prolongation and torsades de pointes in congenital long QT syndrome

Answer 5

potassium rich foods
vomiting and diarrhoea
underwater breath holding
exercise
sudden auditory stimuli
sleep

Question 6

what is the cause of congenital long QT syndrome

Answer 6

mutation in a gene causes abnormal ion channels

prolongs cardiac repolarisation

results in QT prolongation

Question 7

describe the clinical presentation of long QT syndrome

Answer 7

syncope and palpitations - due to polymorphic VT (torsade de pointes)

usually terminates spontaneously but can degenerate into VF which causes sudden death

Question 8

what investigations are indicated for long QT syndrome

Answer 8

ECG

Question 9

describe ECG findings in long QT syndrome

Answer 9

torsade de pointes
QT interval >0.5s

Question 10

describe the acute management of long QT syndrome

Answer 10

treat underlying cause
magnesium infusion
defibrillation if VT occurs

Question 11

describe the long term management of long QT syndrome

Answer 11

beta blockers
avoid QT prolonging drugs and other triggers
pacemaker