Early afterdepolarization abolished by potassium channel opener in a patient with idiopathic long QT syndrome

J Cardiovasc Electrophysiol. 1995 Apr;6(4):279-82. doi: 10.1111/j.1540-8167.1995.tb00400.x.


We describe a 17-year-old boy with idiopathic long QT syndrome and repeated syncopal episodes. Early afterdepolarization (EAD) in the monophasic action potential (MAP) was demonstrated in the posterior septum of the left ventricle. Injection of the potassium channel opener nicorandil decreased EAD and shortened MAP duration. The syncopal episodes due to ventricular fibrillation disappeared after administration of the potassium channel opener.

Publication types

  • Case Reports

MeSH terms

  • Action Potentials / drug effects
  • Adolescent
  • Anti-Arrhythmia Agents / therapeutic use*
  • Electrocardiography / drug effects
  • Humans
  • Long QT Syndrome / complications
  • Long QT Syndrome / drug therapy*
  • Long QT Syndrome / physiopathology
  • Male
  • Niacinamide / analogs & derivatives*
  • Niacinamide / therapeutic use
  • Nicorandil
  • Potassium Channels / drug effects*
  • Syncope / drug therapy
  • Syncope / etiology*
  • Syncope / physiopathology


  • Anti-Arrhythmia Agents
  • Potassium Channels
  • Niacinamide
  • Nicorandil