Proarrhythmia

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Proarrhythmia is a new or more frequent occurrence of pre-existing arrhythmias, paradoxically precipitated by antiarrhythmic therapy, which means it is a side effect associated with the administration of some existing antiarrhythmic drugs, as well as drugs for other indications. In other words, it is a tendency of antiarrhythmic drugs to facilitate emergence of new arrhythmias.

Types of proarrhythmia[edit]

According to the Vaughan Williams classification (VW) of antiarrhythmic drugs, there are 3 main types of Proarrhythmia during treatment with various antiarrhythmic drugs for Atrial Fibrillation or Atrial flutter:

Ventricular proarrhythmia[edit]

Atrial proarrhythmia[edit]

  • Conversion of atrial fribrillation to flutter (usually VW type IC drugs or amiodarone). May be a desired effect.
  • Increase of defibrillation threshold (a potential problem with VW type IC drugs)
  • Provocation of recurrence (probably VW types IA, IC and III drugs). It is rare.

Abnormalities of conduction or impulse formation[edit]

Increased risk[edit]

Clinical pointers[edit]

Class IA drugs[edit]

  • Dose independent, occurring at normal levels.
  • Follow QT interval, keep ms.

Class IC drugs[edit]

  • May be provoked by increased heart rate.
  • Exercise stress tests after loading.

Class III drugs[edit]

  • Dose dependent.
  • Follow bradycardia, prolonged QT closely.

External links[edit]