Long QT syndrome

Etiology

Electrolyte abnormalities

  • Hypokalemia
  • Hypomagnesemia
  • Hypocalcemia
Drugs (selected examples)
  • Class Ia antiarrhythmics (quinidine, procainamide)
  • Class Ic antiarrhythmics (propafenone)
  • Class III antiarrhythmics (amiodarone, bretylium, sotalol)
  • Tricyclic antidepressants
  • Astemizole, terfenadine
  • Antibiotics: erythromycin, trimethoprim-sulfamethoxazole, levofloxacin, ketoconazole, itraconazole
  • Phenothiazines, haldol
  • Prednisone
Miscellaneous
  • Congenital long QT syndrome
  • Third-degree A-V block
  • Second-degree A-V block
  • Left ventricular hypertrophy (LVH)
  • Myocardial ischemia
  • Significant bradycardia
  • Stroke or subarachnoid hemorrhage
  • Hypothermia

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Last updated: December 1, 2014