Rhythm diagnosis in regular wide complex tachycardia: Difference between revisions
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== Diagnostic Algorithms == | ==Diagnostic Algorithms == | ||
*Only for regular rhythms, if irregular consider a-fib with block | *Only for regular rhythms, if irregular consider a-fib with block | ||
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*Assume V-tach until proven otherwise | *Assume V-tach until proven otherwise | ||
=== Brugada Algorithm === | ===Brugada Algorithm === | ||
*Absence of an RS complex in all precordial leads? | *Absence of an RS complex in all precordial leads? | ||
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**If no then possibly SVT w/ aberrant conduction | **If no then possibly SVT w/ aberrant conduction | ||
=== aVR Algorithm === | ===aVR Algorithm === | ||
*In lead aVR: | *In lead aVR: | ||
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**If no then SVT | **If no then SVT | ||
=== 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> === | ||
*Combination of the most specific aspects of the above two algorithms | *Combination of the most specific aspects of the above two algorithms | ||
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**If yes then SVT with aberrancy | **If yes then SVT with aberrancy | ||
=== R-Wave Peak Time Method=== | ===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 | *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 | *Positive Likelihood ratio of 34.8 | ||
=== Lesser Known Criteria=== | ===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]] | *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 | *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 | *"Northwest" axis deviation -- Negative QRS complex in I, AVF and Positive QRS in AVR | ||
== See Also == | ==See Also == | ||
*[[Tachycardia (Wide)]] | *[[Tachycardia (Wide)]] | ||
*[[SVT]] | *[[SVT]] | ||
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*[[PALS: Tachycardia]] | *[[PALS: Tachycardia]] | ||
== References == | ==References == | ||
<references/> | <references/> | ||
[[Category:Cardiology]][[Category:Featured]] | [[Category:Cardiology]][[Category:Featured]] |
Revision as of 05:56, 10 July 2016
Assume ventricular tachycardia until proven otherwise
Background
- Ventricular tachycardia vs. supraventricular tachycardia
Diagnosis
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 abnl |
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
- Only for regular rhythms, if irregular consider a-fib with block
- Only for treatment decision if patient is stable
- Assume V-tach until proven otherwise
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 w/ 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