Search
polymorphic ventricular tachycardia
Ventricular tachycardia characterized by changing QRS morphologies (i.e. torsades de pointes).
Etiology:
1) triggered activity - catecholamine induced
2) functional re-entry
3) ischemia*
* common cause of polymorphic ventricular tachycardia in the absence of QT prolongation
Clinical manifestations:
- syncope
- polymorphic ventricular tachycardia during exercise or emotional stres
Special laboratory:
- exercise stress testing
Management: (also see ventricular tachycardia)
1) hemodynamic instability
-> immediate DC synchronized cardioversion
2) stable patient, chemical cardioversion
3) normal baseline QT interval
a) correct ischemia, electrolyte abnormalities
b) preserved heart function
1] procainamide*
2] sotalol or other beta-blocker
3] amiodarone 150 mg IV over 10 minutes
4] lidocaine 0.5-0.75 mg/kg IV push
c) poor LV ejection fraction
1] amiodarone 150 mg IV over 10 minutes
2] lidocaine 0.5-0.75 mg/kg IV push
3] then DC synchronized cardioversion
4) prolonged baseline QT interval
- treat as torsades de pointes
Specific
catecholaminergic polymorphic ventricular tachycardia; stress-induced polymorphic ventricular tachycardia
familial polymorphic ventricular tachycardia
torsades de pointes
General
ventricular tachycardia (VT)
References
- Manual of Medical Therapeutics, 28th ed, Ewald &
McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 148
- Medical Knowledge Self Assessment Program (MKSAP) 11, 16.
American College of Physicians, Philadelphia 1998, 2012