QRS Complexes in True Torsades de Pointes
Yes, QRS complexes are absolutely visualized in true Torsades de Pointes—in fact, the characteristic "twisting" of QRS complex amplitude and morphology around the isoelectric line is the defining ECG feature of this arrhythmia. 1
Characteristic ECG Features of Torsades de Pointes
The American Heart Association/American College of Cardiology Foundation explicitly describes the QRS complexes in TdP as follows:
A change in the amplitude and morphology (twisting) of the QRS complexes around the isoelectric line is a typical feature of the arrhythmia, though this characteristic twisting morphology may not be evident in all ECG leads 1
The arrhythmia is named "torsade de pointes" (twisting of the points) specifically because of the way the polarity and amplitude of the QRS complexes appear to spiral around the baseline of the ECG 2
The rate of TdP ranges from 160 to 240 beats per minute, which is notably slower than ventricular fibrillation and allows for QRS complex visualization 1
Distinguishing TdP from Ventricular Fibrillation
This is a critical clinical distinction:
In contrast to ventricular fibrillation (which shows rapid, grossly irregular electrical activity with marked variability and no discernible QRS complexes), TdP maintains identifiable QRS complexes with the characteristic twisting pattern 1
Ventricular fibrillation typically has rates >300 bpm with cycle lengths <200 ms, making individual complexes indistinguishable, whereas TdP maintains slower rates with visible QRS morphology 1
TdP frequently terminates spontaneously, with the last 2 to 3 beats showing slowing of the arrhythmia, though it can degenerate into ventricular fibrillation and cause sudden cardiac death 1
Additional ECG Characteristics
Beyond the twisting QRS complexes, TdP has other recognizable features:
Episodes typically show a "warm-up phenomenon" with the first few beats exhibiting longer cycle lengths than subsequent arrhythmia complexes 1
The arrhythmia usually starts with a short-long-short pattern of R-R cycles, consisting of a premature ventricular complex followed by a compensatory pause and then another PVC 1, 3
TdP is characterized by a waxing and waning QRS amplitude, and while the twisting of the points is characteristic, it may not always be seen if the episode is nonsustained or if only a limited number of leads are available 1
Clinical Pitfall
The term "torsade de pointes" should be confined to polymorphic tachycardias with marked QT-interval prolongation (>500 ms) and QT-U deformity, as they represent a distinct mechanistic and therapeutic entity 1. Using this term for polymorphic ventricular arrhythmias without QT prolongation is inappropriate and can lead to incorrect management.