How is torsade de pointes defined?

Updated: Jan 31, 2017
  • Author: Jatin Dave, MD, MPH; Chief Editor: Mikhael F El-Chami, MD  more...
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Answer

Answer

The original report described regular variation of the morphology of the QRS vector from positive to net negative and back again. This was symbolically termed torsade de pointes, or "twisting of the point" about the isoelectric axis, because it reminded the authors of the torsade de pointes movement in ballet. Most cases exhibit polymorphism, but the axis changes may not have regularity.

The definition also requires that the QT interval be increased markedly (often to ≥600 msec). Cases of polymorphous ventricular tachycardia in which the QT interval is not prolonged are treated as generic ventricular tachycardia. Torsade usually occurs in bursts that are not sustained; thus, the rhythm strip usually shows the patient's baseline QT prolongation.


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