Lightning Learning: Long QT Syndrome
““Long QT Syndrome affects 1 in 2,500 people worldwide and is a congenital (or acquired) disorder that causes the QT interval to become prolonged.””
What?
Congenital or acquired disorder which causes the QT interval to be prolonged (>450ms)
Genetic mutation affects Na and K channels
Drugs e.g. TCA, SSRIs, haloperidol and many more
Electrolyte disturbance e.g. hypokalaemia and hypocalcaemia
Heart disease
Prolonged repolarisation of the ventricles which causes arrhythmias. Diagnosed with aid of ECG and Schwartz criteria. Romano-Ward syndrome and Jervell and Lange-Nielsen syndrome are genetic forms of long QT syndrome.
Why?
Affects 1:2500 people worldwide. Patients may remain asymptomatic BUT Long QT syndrome is Associated with syncope, especially on exertion and... SUDDEN CARDIAC ARREST
It is often misdiagnosed as epilepsy. Management for congenital cases will be through lifestyle change, beta-blocker therapy and ICD. Patients will need to avoid extreme exertion.
Further Reading:
- Medscape: Long QT Syndrome Workup
- Life in the Fast Lane: Long QT Syndrome
- BMJ Best Practice: Long QT Syndrome
