Symptoms What to look for/be aware of Investigation & treatment and/or referral pathway Further reading

Long QT

  • An association between Rett Syndrome and Long QT has been noted, which may arise more commonly with increasing age.
  • There are multiple meds which can increase the QT interval.
  • Common drugs to avoid: Fluoxetine, Azithromycin.
  • Entromycin with other meds can be lethal.
  • Baseline ECG should be undertaken at diagnosis.
  • ECG should be undertaken where there is suspicion of ECG abnormalities from clinical history and reported observational history.
  • ECG should be undertaken where there is desire to prescribe medication which is known to potentially cause QT changes with 48 hour ECG recording obtained prior to medication change.
  • Where negative, once treatment is prescribed, repeat ECG should be undertaken for seven consecutive days. (May be adjusted depending on rapidity of action of the drug).
  • If positive for ECG changes and/or prolonged QT interval, drug should be withdrawn and ECG recording continued to ensure return to pre-treatment status.
  • Where possible, avoid drugs which prolong QT interval, where there is alternative available.
  • ECG should be conducted as part of pre-surgical assessment especially when anaesthetic is being given.
  • Website list/smartphone app for drugs to avoid with Long QT

Cardiovascular dysregulation

  • Dysregulation of cardiovascular parameters. Heart rate, BP, peripheral vasoconstriction, may change markedly within seconds.
  • Monitor for QTc prolongation at least annually.
  • QTc may vary markedly within a short space of time.
  • Beware of/ avoid medications causing QTc prolongation.


  • Very poor flow to extremities especially lower leg/feet.
  • Risk of severe chilblains.
  • Doppler Scan.
  • Thermal socks/footwear/foot spa.
  • Warming slowly when cold, elevating feet.
  • Consider Amlodipine for severe cases before considering GTN patches to decrease risk of severe headaches.
  • Severe cases consider sympathectomy.
  • Glyceryl trinitrate (GTN) patches may be helpful.