polymorphic ventricular tachycardia

Introduction

Ventricular tachycardia characterized by changing QRS morphologies (i.e. torsades de pointes).

Etiology

• triggered activity - catecholamine induced
• functional re-entry
• ischemia*

* common cause of polymorphic ventricular tachycardia in the absence of QT prolongation

Clinical manifestations

• syncope
• polymorphic ventricular tachycardia during exercise or emotional stres

Diagnostic procedures

• exercise stress testing

Management

(also see ventricular tachycardia)

• hemodynamic instability
  • immediate DC synchronized cardioversion
• stable patient, chemical cardioversion
• normal baseline QT interval
  • correct ischemia, electrolyte abnormalities
  • preserved heart function
    • procainamide*
    • sotalol or other beta-blocker
    • amiodarone 150 mg IV over 10 minutes
    • lidocaine 0.5-0.75 mg/kg IV push
  • poor LV ejection fraction
    • amiodarone 150 mg IV over 10 minutes
    • lidocaine 0.5-0.75 mg/kg IV push
    • then DC synchronized cardioversion
• prolonged baseline QT interval
  • treat as torsades de pointes

More general terms

• ventricular tachycardia (VT)

More specific terms

• catecholaminergic polymorphic ventricular tachycardia; stress-induced polymorphic ventricular tachycardia
• familial polymorphic ventricular tachycardia
• torsades de pointes