Rhythm diagnosis in regular wide complex tachycardia: Difference between revisions
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*Some patients with '''regular''' [[wide complex tachycardia]] do not have [[ventricular tachycardia]] | *Some patients with '''regular''' [[wide complex tachycardia]] do not have [[ventricular tachycardia]] | ||
*However, [[ventricular tachycardia]] is a dangerous rhythm that must be treated emergently | *However, [[ventricular tachycardia]] is a dangerous rhythm that must be treated emergently | ||
==Differential Diagnosis== | |||
{{Tachycardia (wide) DDX}} | |||
==Evaluation== | ==Evaluation== | ||
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==Diagnostic Algorithms== | ==Diagnostic Algorithms== | ||
'''Assume [[ventricular tachycardia]] until proven otherwise''' | |||
*Only for regular rhythms, if irregular consider a-fib with block | *Only for regular rhythms, if irregular consider a-fib with block | ||
*Only for treatment decision if patient is stable | *Only for treatment decision if patient is stable | ||
===Brugada Algorithm=== | ===Brugada Algorithm=== | ||
*Absence of an RS complex in all precordial leads? | *Absence of an RS complex in all precordial leads? | ||
**If yes then VT | **If yes then VT | ||
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===aVR Algorithm=== | ===aVR Algorithm=== | ||
*In lead aVR: | *In lead aVR: | ||
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===Niemann Algorithm<ref>James Niemann MD FACEP is EM Faculty at Harbor-UCLA Medical Center and prominent resuscitation researcher</ref>=== | ===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]] | [[File:Wide Complex Tachycardia.png|thumb|Neimann Algorithm for Regular WCT]] | ||
*Combination of the most specific aspects of the above two algorithms | *Combination of the most specific aspects of the above two algorithms | ||
Acronym: <big>CARMA</big> → '''Concordance → aVR →Regular → Morphology →AV dissociation''' | Acronym: <big>CARMA</big> → '''Concordance → aVR →Regular → Morphology →AV dissociation''' | ||
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==See Also== | ==See Also== | ||
*[[ | *[[Wide-complex tachycardia]] | ||
*[[SVT]] | *[[SVT]] | ||
*[[ACLS: Tachycardia]] | *[[ACLS: Tachycardia]] | ||
*[[PALS: Tachycardia]] | *[[PALS: Tachycardia]] | ||
Latest revision as of 18:09, 12 August 2020
Assume ventricular tachycardia until proven otherwise
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
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)
- Regular
- Monomorphic ventricular tachycardia
- PSVT with aberrant conduction:
- PSVT with bundle branch block^
- PSVT with accessory pathway
- Atrial flutter with bundle branch block^
- Sinus tachycardia with bundle branch block^
- Accelerated idioventricular rhythm (consider if less than or ~120 bpm)
- Metabolic
- Irregular
- Atrial fibrillation/atrial flutter with variable AV conduction AND bundle branch block^
- Atrial fibrillation/atrial flutter with variable AV conduction AND accessory pathway (e.g. WPW)
- Atrial fibrillation + hyperkalemia
- Polymorphic ventricular tachycardia
^Fixed or rate-related
Evaluation
| 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]
- 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
- If no then continue
- Is there evidence of AV dissociation/Capture beats?
- 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
- 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
- ↑ James Niemann MD FACEP is EM Faculty at Harbor-UCLA Medical Center and prominent resuscitation researcher
- ↑ 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
- ↑ Szelenyi Z, et al. Acad Emerg Med 2013;20:1121- 1130
- ↑ 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
- ↑ Brugada, Circulation; Griffith MJ et al. Lancet 1994;343:386-388
- ↑ Wellens HJJ et al. Am J Med 1978; 64:27-33