3.9 Long QT Syndrome

Question 1

List the causes of Long QT syndrome

Answer 1

Congenital:
Jervell Lange Nielsen
Auto Recess
A/w varying cardiac symptoms congen deaf sudden death
2. Romano-Ward
AD

Acquired

Question 2

Acquired

Answer 2

Electrolyte imbalance

Severe Nutritional deficit

Sympathetic Stimulation
-Pain / SAH

Hypothermia

Drugs which cause TDP

Question 3

Drugs which cause TDP

Answer 3

Antiarr

1. sotalol
2. Flecainide
3. Amio
4. Quinidine

Antimicrobial

1. Erythromycin
2. Clarithromycin
3. Fluconazole

APS / Antidepressant

1. Chlorpromazine
2. Fluoxetine
3. Haloperidol

Question 4

CVS Risks long QT

Answer 4

Mutations of cardiac ion channels
- inadequate ventricular repolarisation

Risk malignant Ventricular Arr
TDP
=

Arr spontaneous return sinus
or progress fatal VF

Question 5

Anaesthetic consideration

Answer 5

Main aim to avoid precipitation of potentially harmful arr

1) Preop
Anaes Hx & Exam
Including:
previous CVS Sy
Attacks
Treatment

Preop ECG to assess QT & QTc interval
- may be normal

Cardiology r/v + optimise meds
Contin b bloq meds periop
Adequate if Valsalva doesnt alter QTc

Preop U+E w/ correction prn

Question 6

Intraop

stress reponse

Answer 6

Aim to minimise development of arr
limiting surgical stress response

1) consider sedative premed
2) Obtund pressor response to airway instrumentation using Opioids

3) Adequate analgesia
Consider regional

4) IPPV minimise hypercarbia + High intrathoracic pressures

Question 7

Other Intraop tech

Answer 7

Avoid hypothermia w/ active warming devices

Consider invasive BP monitoring
- freq electrolyte monitoring

AVOID drugs prolong QTc interval
precipitate arr
Ketamine
Sux
Atropine
Glyco
Neo

Have neccessary resus + pacing equipment

Rx arr promptly
if TDP -> MgSo4 2g over 20 min
repeat

Commence infusion
3-20mg/min if no improvement

Question 8

Post Op

Answer 8

1) continous ecg until emergence
or longer if major

2) Adequate analgesia
3) Calm