Submitted by Dr A Röschl on Tue, 01/14/2025 - 02:03
What can we learn from this 3-channel ECG?
A sinus rhythm can be seen in the left half of the image, which merges into a ventricular tachycardia on the right. The QRS complexes of the VT change their shape and polarity, this is called polymorphic.
The question is: can this be called TdP (Torsade de Pointes) tachycardia or not? The clear answer is: no! A polymorphic VT may only be called TdP if there is a prolonged QT/QTc duration in the native rhythm. This is obviously not the case here. Therefore, the term polymorphic VT is retained here
Torsades de pointes, or polymorphic ventricular tachycardia, is a ventricular tachycardia precipitated by and associated with long QT Syndrome. Long QT Syndrome can be congenital or acquired. Torsades is life-threatening, and can be made worse by many drugs, including some of the drugs used to treat VT. The rate is usually 150 - 250 / min. and the appearance is of a wide-complex tachycardia with QRS morphology changes. In some leads, it will appear as if it is "twisting" around the isoelectric line, giving it the French name, Torsades de pointes, a ballet term meaning twisting of the points. For a thorough discussion of Torsades, check this LINK.
