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[[File:VT_algorythm_en.png|800px|thumb|left|SVT vs VT algorhytm. Adapted from <cite>ACC</cite>]]
 
[[File:VT_algorythm_en.png|800px|thumb|left|SVT vs VT algorhytm. Adapted from <cite>ACC</cite>]]
 
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==ECG algorithms to differentiate wide QRS-complex tachycardias==
== Brugada criteria ==
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Several ECG algorithms have been developed to differentiate wide QRS-complex tachycardias. Most of them performed very well in the population they were based upon. A recent review tested five commonly used algorithms in a control population and found that each of them only performed reasonably well in differentiating VT from SVT (accuracy 66-77%).<cite>Jastrzekbsi</cite> The five criteria tested were:
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* Brugada algorithm (below).<cite>Brug1</cite> This is the most commonly used algorithm. SN 89%, SP 59.2%.
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* The lead II R-wave-peak-time (below). <cite>Brugada2</cite> Sensitivity 60%, specificity 82.7%.
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* The aVR algorithm (below). <cite>Vereckei</cite> Sensitivity 87.1%, specificity 48%.
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* The Bayesian algorithm.<cite>Lau</cite> This calculates a score based on 19 morpologic features. Sensitivity 89%, specificity 52%.
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* The Griffith algorithm (below).<cite>Griffith</cite> Sensitivity 94.2%, specificity 39.8%.
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== Brugada algorithm ==
 
[[File:Brugada_algorithm.svg|500px|thumb|left]]
 
[[File:Brugada_algorithm.svg|500px|thumb|left]]
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== Ultrasimple Brugada criterion ==
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== Ultrasimple Brugada criterion: RW to peak Time (RWPT)  ==
 
[[File:RWPT.svg|thumb|right|300px|R-wave to Peak Time ≥ 50ms in lead II strongly suggests VT]]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 <cite>Brugada2</cite>. 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.
 
[[File:RWPT.svg|thumb|right|300px|R-wave to Peak Time ≥ 50ms in lead II strongly suggests VT]]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 <cite>Brugada2</cite>. 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.
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== Vereckei algorithm <cite>Vereckei</cite>==
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== Vereckei aVR algorithm <cite>Vereckei</cite>==
 
[[File:Vereckei_algorithm.png|500px|thumb|left]]
 
[[File:Vereckei_algorithm.png|500px|thumb|left]]
 
[[File:vivt.png|300px|thumb|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]]
 
[[File:vivt.png|300px|thumb|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]]
 
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== Griffith algorithm ==
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The Griffith algorithm <cite>Griffith</cite>reverses the diagnostic strategy:  unless simple rules for a positive diagnosis of supraventricular tachycardia are satisfied, ventricular tachycardia is diagnosed by default. The algorithm only looks at bundle brach block morphology. Supraventricular tachycardia is diagnoses when ECG findings match typical bundle branch block:
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* LBBB: rS or QS wave in leads V1 and V2, delay to S wave nadir < 70 ms, and R wave and no Q wave in lead V6
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* RBBB: rSR' wave in lead V1 and an RS wave in lead V6, with R wave height greater than S wave depth
    
==Examples==
 
==Examples==
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#Vereckei pmid=17272358
 
#Vereckei pmid=17272358
 
#Brugada2 pmid=20215043  
 
#Brugada2 pmid=20215043  
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#Jastrzekbsi pmid=22333239
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#Lau pmid=11060873
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#Griffith pmid=7905552
 
</biblio>
 
</biblio>

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