Rhythm diagnosis in regular wide complex tachycardia: Difference between revisions

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==See Also==
<big>''Assume [[ventricular tachycardia]] until proven otherwise''</big>
Cards: Tachycardia (Wide)
 
==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


==Brugada's Criteria==
===Niemann Algorithm<ref>James Niemann MD FACEP is EM Faculty at Harbor-UCLA Medical Center and prominent resuscitation researcher</ref>===
#Lack of precordial RS complex. yes=VT
[[File:Wide Complex Tachycardia.png|thumb|Neimann Algorithm for Regular WCT]]
#R onset to S nadir > 100ms of 2.5 sm boxes in one precordial lead. yes=VT
*Combination of the most specific aspects of the above two algorithms
#AV dissociation. yes=VT
Acronym: <big>CARMA</big> → Concordance → aVR →Regular → Morphology →AV dissociation
#Morphology criteria for VT present both in precordial leads v1-2 and v6. yes-VT


==VTach vs. SVT ==
*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>
===V TACH===
**If yes then VT
#age >50
**If no then continue
#h/o MI, CHF, CABG, ASHD, mitral valve prolapse, prev v tach
*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>
#cannon A waves
**If yes then VT  [[File:concord.jpg|thumb|Example of concordance in precordial leads]] [[File:disconcord.jpg|thumb|Example of disconcordance in precordial leads]]
#variation in arterial pulse
**If no then continue
#variable first heat sound
*Is there evidence of AV dissociation/Capture beats?  [[File:capture.jpg|thumb|Example of capture beat]]
#fusion beats
**If yes then VT
#AV dissociation
**If no then continue
#QRS > 0.14sec
*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>
#extreme LAD <-30degree
**If no then VT
#no response to vagal maneuvers
**If yes then SVT with aberrancy
#specific QRS pattern- V1- R, qR or RS, V6- S, rS or qR
#concordance


===SVT With Aberrancy===
===R-Wave Peak Time Method===
#age <35
*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
#mitral valve prolapse, esp c h/o WPW
*Positive Likelihood ratio of 34.8
#prev SVT
#no cannon A waves
#no variability in arterial pulse
#no variability of first heart sound
#no fusion beats
#p waves preceding qrs cmplx
#QRS usually <0.14 sec
#axis normal or slightly abnormal
#slow or terminate with vagal maneuver
#specific QRS pattern- V1-rsR', V6qRs (R wave in V1 or V2 < 1 box wide)
#In Peds SVT w/ Aberrancy = #1 cause of wide tachycardia


==Source ==
===Lesser Known Criteria===
7/2/09 Pani
*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


4/2/10 Niemann
==See Also==
*[[Wide-complex tachycardia]]
*[[SVT]]
*[[ACLS: Tachycardia]]
*[[PALS: Tachycardia]]


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

Latest revision as of 09:24, 22 March 2026

Assume ventricular tachycardia until proven otherwise

Background

Differential Diagnosis

Wide-complex tachycardia

Assume any wide-complex tachycardia is ventricular tachycardia until proven otherwise (it is safer to incorrectly assume a ventricular dysrhythmia than supraventricular tachycardia with abberancy)

^Fixed or rate-related

Evaluation

Monomorphic ventricular tachycardia
PSVT at ~180 bpm
Termination of PSVT following adenosine
Factor
 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 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[1]

Neimann Algorithm for Regular WCT
  • Combination of the most specific aspects of the above two algorithms

Acronym: CARMA → Concordance → aVR →Regular → Morphology →AV dissociation

  • Presence of an initial R wave in aVR? [2][3]
    • If yes then VT
    • If no then continue
  • Is there concordance (monophasic with same polarity) in all of the precordial leads? [4]
    • If yes then VT
      Example of concordance in precordial leads
      Example of disconcordance in precordial leads
    • If no then continue
  • Is there evidence of AV dissociation/Capture beats?
    Example of capture beat
    • If yes then VT
    • If no then continue
  • Is the QRS morphology in V1 and V6 consistent with either LBBB or RBBB? [5][6]
    • 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
    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

References

  1. ↑ James Niemann MD FACEP is EM Faculty at Harbor-UCLA Medical Center and prominent resuscitation researcher
  2. ↑ 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
  3. ↑ Szelenyi Z, et al. Acad Emerg Med 2013;20:1121- 1130
  4. ↑ 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
  5. ↑ Brugada, Circulation; Griffith MJ et al. Lancet 1994;343:386-388
  6. ↑ Wellens HJJ et al. Am J Med 1978; 64:27-33
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