# Approach to the Wide Complex Tachycardia

During wide complex tachycardia (heart rate > 100/min, QRS > 0.12 sec) the differentiation between supraventricular and ventricular origin of the arrhythmia is important to guide therapy. Several algorithms have been developed to aid in this differentiation (below). It is important to keep in mind that a good estimate of VT versus SVT can be made based on the clinical vignette:

• 'Horizontal entrance' into the ER. Older patient with previous myocardial infarction = most likely VT
• Younger patient with known paroxysmal tachycardias and who is hemodynamically stable = most like SVT

## The ACC algorithm [1]

SVT vs VT algorhytm. Adapted from [1]

Morphological criteria (if the above criteria are inconclusive)
LBBB pattern
Initial R more than 40ms? Yes => VT
Slurred or notched downwards leg of S wave in leads V1 or V2 Yes => VT
Beginning of Q to nadir QS >60 ms in V1 or V2? Yes => VT LR >50:1
Q or QS in V6? Yes => VT LR >50:1
RBBB pattern
Monofasic R or qR in V1? Yes => VT
R taller than R' (rabbit-ear sign)? Yes => VT LR >50:1
rS in V6? Yes => VT LR >50:1

In 2010 Joseph Brugada et al. published a new criterion to differentiate VT from SVT in wide complex tachycardias: the R wave peak time in Lead II [2]. They suggest measuring the duration of onset of the QRS to the first change in polarity (either nadir Q or peak R) in lead II. If the RWPT is ≥ 50ms the likelihood of a VT very high (positive likelihood ratio 34.8). This criterion was successful in their own population of 163 selected patients and is awaiting prospective testing in a larger trial.

## Vereckei algorithm [3]

If the distance traveled on the Y axis in the initial 40ms of the QRS complex is smaller than that traveled in the terminal 40ms of the QRS complex, a VT is much more likely

## Referenties

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1. Error fetching PMID 14563598: [ACC]
2. Error fetching PMID 20215043: [Brugada2]
3. Error fetching PMID 17272358: [Vereckei]
4. Error fetching PMID 2022022: [Brug1]

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