Prolonged Q - T interval

Question 1

What is long QT syndrome?

Answer 1

inherited condition associated with delayed repolarisation of the ventricles

• important to recognise as it may lead to ventricular tachycardia / torsade de pointes and can therefore cause collapse/sudden death

Question 2

Which cardiovascular drugs can cause a prolonged QT interval?

Answer 2

1. Amiadorone
2. Sotalol
3. Class 1 a anti arrhythmics

Question 3

Which psychiatric drugs can cause a prolonged QT interval?

Answer 3

1. Tricyclic antidepressants - Amitriptyline
2. SSRI - Citalopram
3. Haloperidol

Question 4

Which medical conditions can cause a prolonged QT interval?

Answer 4

1. Electrolyte
   - hypocalcaemia / hypokalaemia / hypomagnesia
2. Acute MI
3. Myocarditis

Question 5

Which antibiotic causes a prolonged QT interval?

Answer 5

Erythromycin

Question 6

What is ‘Torsade de Pointes’?

Answer 6

A form of polymorphic ventricuar tachycardia associated with a long QT interval

• this may deteriorate into ventricular fibrillation and hence lead to sudden death

Question 7

What is the management of Torsade de Pointes?

Answer 7

IV magnesium sulphate