OzEMedicine - Wiki for Australian Emergency Medicine Doctors

see also:

• cardiac arrhythmias
• ventricular tachycardia (VT)
• LITFL - a case of prolonged QTc with R on T bigeminy leading to torsades

ref: EMedicine article on torsade de pointes

• torsade is an inherently unstable rhythm and will either revert or degenerate to VF, thus commence Rx as soon as it is recognised.
• Most (75-82%) torsade de pointes (TDP) rhythms are started by a pause. Pacing at rates up to 140 bpm may prevent the ventricular pauses that allow TDP to originate.
• often associated with prolonged QTc on ECG which may be hereditary, drug-induced, or have other causes.
• a rare cause is Brugada syndrome which if untreated may be fatal within 2 years.

• oxygen, cardiac monitor, IV access, move to full resuscitative facilities and procedures as for VT
• if in extremis, then DC reversion ASAP
• treat hypokalaemia if present
• stop all drugs which prolong QTc
• iv magnesium sulphate 2-4g initially
  • usually very effective even in patients with normal Mg levels
  • if fails, repeat dose but watch for Mg toxicity including impaired NM function
• consider:
  • overdrive pacing to HR of 140
  • iv isoprenaline (isoproterenol) infusion to maintain HR of 90-100bpm to prevent recurrence
  • short-acting beta blockers such as iv esmolol can be tried in patients with congenital prolonged QT syndrome but should NOT be used in cocaine-induced cases.