Arrhythmia: Long QT syndrome (Complete)

Question 1

What is long QT syndrome?

Answer 1

Inherited or aquired condition characterised by delayed repolarisation of the ventricles resulting in a prolonged QT interval

Question 2

What can long QT syndrome progress to?

Answer 2

Ventricular tacchycardia and then sudden cardiac death

Question 3

What are 2 congenital causes of a prolonged QT interval?

Answer 3

Jervell-Lange-Nielsen syndrome (includes deafness and is due to an abnormal potassium channel)

Romano-Ward syndrome (no deafness)

Question 4

List drugs which can cause a prolonged QT interval (8)

Answer 4

Antiarrhythmics: e.g. amiodarone, sotalol (beta-blocker), class 1A antiarrhythmics

TCAs and SSRIs (especially citalopram)

Methadone (opiod)

Chloroquine (antimalarial)

Terfenadine (antihistamine)

Macrolide ABs (e.g. erythromycin)

Anti-psychotics (e.g. Haloperidol)

Ondanestron (anti-emetic for chemotherapy)

Question 5

What are non congenital/drug related causes of a prolonged QT interval? (8)

Answer 5

Hypocalcaemia

Hypokalaemia

Hypomagnasaemia

Acute MI

Myocarditis

Hypothermia

SAH

Question 6

What are some of the main presentations of long QT syndrome? (5)

Answer 6

Depends on the type of long QT syndrome:

Long QT1: Exertional syncope (e.g. often occurs when swimming)

Long QT2: Syncope during emotional stress, exercise or auditory stimuli.

Long QT3: Events occur at night or at rest

May be picked up on ECG

Sudden cardiac death (common cause in young people)

Question 7

What are the main investigations for long QT syndrome? (4)

Answer 7

Bedside: ECG (would show signs prolonged QT intervals)

Bloods:
U&Es: Serum pottasium
serum magnesium
serum calcium (can cause long QT syndrome)

Question 8

What is the management plan for patients with long QT syndrome?

Answer 8

Conservative/lifestyle:
Avoid drugs which can cause QT syndrome
Avoid strenous exercise

Pharmacological:
Beta-blockers (AVOID SOLTALOL)

Surgical: Implantable cardioverter defibrilators (in severe cases)