# 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 algorhythms 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 algorhythm [1]

SVT vs VT algorhytm. Adapted from [1]

Brugada criteria to differentiate SVT from VT [2]
Are there fusion or capture beats? (this is not an item from Brugada, it is however very specific Yes? => VT specificy=100%
RS complexen missing in the chest leads? Yes? => VT sensitivity=21% specificity=100%
RS-interval in one of the cheast leads > 100 msec (in the absence of anti-arrhythmics)? Yes? => VT sensitivity=66% specificity=98%
AV-dissociation? Yes? => probably VT (Note AVNRT can also present with AV dissociation!) sensitivity=82% specifity=98%
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

## 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

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

All Medline abstracts: PubMed | HubMed