Ver el código de «Rhythm diagnosis in regular wide complex tachycardia»

<big>''Assume [[ventricular tachycardia]] until proven otherwise''</big>

==Background==
*Some patients with '''regular''' [[wide complex tachycardia]] do not have [[ventricular tachycardia]]
*However, [[ventricular tachycardia]] is a dangerous rhythm that must be treated emergently

==Differential Diagnosis==
{{Tachycardia (wide) DDX}}

==Evaluation==
[[File:Electrocardiogram of Ventricular Tachycardia.png|thumb|Monomorphic ventricular tachycardia]]
[[File:SVT12.jpg|thumb|PSVT at ~180 bpm]]
[[File:Hr scan.jpg|thumb|Termination of PSVT following adenosine]]
{| class="wikitable"
|-
| '''Factor'''<br>
| '''[[V-Tach]]''' 
| '''[[SVT]] with Aberrancy'''
|-
| Age 
| >50 
| <35
|-
| History 
| MI, CHF, CABG, MVR 
| MVR, WPW
|-
| Cannon A Waves 
| Present 
| Absent
|-
| Arterial Pulse 
| Variation 
| No variation
|-
| First heart sound 
| Variable 
| Not variable
|-
| Fusion Beats 
| Present 
| Absent
|-
| AV dissociation 
| Present 
| Absent
|-
| QRS 
| >0.14sec 
| <0.14sec
|-
| Axis 
| Extreme LAD (< -30) 
| Normal or slightly abnormal
|-
| Vagal Maneuvers 
| No response 
| Slows or terminates
|-
| 
QRS morphology 

(RBBB-like pattern)

| 
V1 - R or qR 

V6 - rS

| 
V1 - rsR' 

V6 - R(slurredS)

|-
| 
QRS morphology 

(LBBB-like pattern)

| 
V1 or V2 - Broad R wave (>40msec) 

V6 - Any Q or QS

| 
V1 - rS or&nbsp;QS 

V6 - qRs

|}

==Diagnostic Algorithms==
'''Assume [[ventricular tachycardia]] until proven otherwise'''
*Only for regular rhythms, if irregular consider a-fib with block
*Only for treatment decision if patient is stable 

===Brugada Algorithm===
*Absence of an RS complex in all precordial leads? 
**If yes then VT 
**If no then continue
*RS interval >100ms in any precordial lead? (onset of R wave to deepest part of S wave) 
**If yes then VT 
**If no then continue
*AV dissociation? 
**If yes then VT 
**If no then continue
*Morphology criteria for v-tach present in both V1-2 and V6? 
**If yes then VT 
**If no then possibly SVT with aberrant conduction

===aVR Algorithm===
*In lead aVR:

*Presence of an initial R wave? 
**If yes then VT 
**If no then continue
*Presence of an initial r or q wave >40ms 
**If yes then VT 
**If no then continue
*Presence of a notch on descending limb of a negative onset, predominantly negative QRS? 
**If yes then VT 
**If no then continue
*Ventricular activation-velocity ratio (Vi/Vt) ≤1? 
**If yes then VT 
**If no then SVT

===Niemann Algorithm<ref>James Niemann MD FACEP is EM Faculty at Harbor-UCLA Medical Center and prominent resuscitation researcher</ref>===
[[File:Wide Complex Tachycardia.png|thumb|Neimann Algorithm for Regular WCT]]
*Combination of the most specific aspects of the above two algorithms
Acronym: <big>CARMA</big> → '''Concordance → aVR →Regular → Morphology →AV dissociation'''

*Presence of an initial '''R wave in aVR'''? <ref>Vereckei A et al. New algorithm using only lead aVR for differential diagnosis of wide QRS complex tachy- cardia. Heart Rhythm 2008; 5:89-98</ref><ref>Szelenyi Z, et al. Acad Emerg Med 2013;20:1121- 1130</ref>
**If yes then VT 
**If no then continue
*Is there '''concordance''' (monophasic with same polarity) in all of the precordial leads? <ref>Brugada P et al. A new approach to the differential diagnosis of a regular tachycardia with a wide QRS complex. Circulation 1991;83:1649-1659</ref>
**If yes then VT  [[File:concord.jpg|thumb|Example of concordance in precordial leads]] [[File:disconcord.jpg|thumb|Example of disconcordance in precordial leads]]
**If no then continue
*Is there evidence of '''AV dissociation/Capture beats'''?  [[File:capture.jpg|thumb|Example of capture beat]]
**If yes then VT 
**If no then continue
*Is the QRS '''morphology''' in V1 and V6 consistent with either '''[http://wikem.org/wiki/Left_bundle_branch_block LBBB]''' or '''[http://wikem.org/wiki/Right_bundle_branch_block RBBB]'''? <ref>Brugada, Circulation; Griffith MJ et al. Lancet 1994;343:386-388</ref><ref>Wellens HJJ et al. Am J Med 1978; 64:27-33</ref>
**If no then VT 
**If yes then SVT with aberrancy

===R-Wave Peak Time Method===
*In lead II, if the TIME in (ms) it takes the R wave to go from the isoelectric line to its peak voltage is greater than 50ms, it is VT
*Positive Likelihood ratio of 34.8

===Lesser Known Criteria===
*Josephson's sign --- notching or slurring near the nadir of the S-wave is characteristic of V. Tach[[File:Josephson’s sign.jpg|thumbnail|Josephson's Sign Vtach]]
*Rsr' sign --- A taller left R wave in v1-v2 is very specific for VT, as opposed in a RBBB where the second/right R-wave (R') is taller
*"Northwest" axis deviation -- Negative QRS complex in I, AVF and Positive QRS in AVR

==See Also==
*[[Wide-complex tachycardia]]
*[[SVT]]
*[[ACLS: Tachycardia]]
*[[PALS: Tachycardia]]

==References==
<references/>
[[Category:Cardiology]][[Category:Featured]]