Torsades de Pointes

Key points

• Torsades ('twisting of the points'): rare polymorphic VT associated with long QT; may deteriorate into VF → sudden death.
• Causes of long QT: congenital (Jervell-Lange-Nielsen, Romano-Ward) · antiarrhythmics (amiodarone, sotalol, class 1a) · other drugs (methadone, erythromycin).
• Drug-induced QT prolongation acts via cardiac potassium channels.
• Treatment: IV magnesium (e.g. 2 g).