Wide complex tachycardia overview: Difference between revisions

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== Overview ==   
== Overview ==   
 
Wide complex tachycardia is a cardiac rhythm of more than 100 beats per minute with a [[QRS duration]] of 120 milliseconds or more.  It is critical to differentiate whether the wide complex tachycardia is of ventricular origin and is [[ventricular tachycardia]] ([[VT]]), or if it is of supraventricular origin with aberrant conduction ([[SVT]] with aberrancy).  Rapid differentiation between these two causes of wide complex tachycardia is absolutely critical because the treatment options are quite different for [[VT]] versus [[SVT]] with aberrancy.  '''Wide complex tachycardia should be assumed to be due to [[ventricular tachycardia]] even in a hemodynamically stable patient unless proven otherwise,''' and first line treatment with [[verapamil]] should be avoided.
'''Wide complex tachycardia''' is defined as a cardiac rhythm of more than 100 beats per minute with a [[QRS duration]] of 120 milliseconds or more.  It is critical to differentiate whether the wide complex tachycardia is of ventricular origin and is [[ventricular tachycardia]], or if it is of supraventricular origin with aberrant conduction ([[SVT]] with aberrancy).  Differentiating between these two cause of the wide complex tachycardia is critical because the treatment options are quite different for [[VT]] versus [[SVT]] with aberrancy.  


==Causes==
==Causes==
Wide complex tachycardia will be due to [[VT]] in 80% of cases if there is a history of [[myocardial infarction]] ([[MI]]). Only 7% of patients with [[SVT]] with aberrancy will have had a prior [[myocardial infarction]] ([[MI]]).  Wide complex tachycardia will be due to [[VT]] in 98% of cases if there's a history of [[structural heart disease]].  
A wide complex tachycardia is either of ventricular origin ([[ventricular tachycardia]] or [[VT]]), of supraventricular origin with aberrant conduction ([[SVT]] with aberrancy), of supraventricular origin and is conducted down a [[bypass tract]] such as in [[Wolff-Parkinson-White syndrome]] ([[WPW]]), or is due to a pacemaker malfunction.  Approximately 80% of wide complex tachycardias are due to [[ventricular tachycardia]].<ref name="pmid16951728">{{cite journal |author=Lam P, Saba S |title=Approach to the evaluation and management of wide complex tachycardias |journal=[[Indian Pacing and Electrophysiology Journal]] |volume=2 |issue=4 |pages=120–6 |year=2002 |pmid=16951728 |pmc=1557420 |doi= |url=http://www.ipej.org/2/120 |issn= |accessdate=2013-08-04}}</ref>


==Differential Diagnosis of Wide Complex Tachycardia==
==Differential Diagnosis of Wide Complex Tachycardia: Distinguishing VT from SVT==
===EKG Findings Suggestive of VT===
''For more detailed information regarding how to differentiate VT from SVT please view the [[Wide complex tachycardia differential diagnosis|differential diagnosis page]] or click [[Wide complex tachycardia differential diagnosis|here]].''
====History of Ischemic Heart Disease====
A history of [[ischemic heart disease]] or structural heart disease suggests VT.  Wide complex tachycardia will be due to [[VT]] in 80% of cases if there is a history of [[myocardial infarction]] ([[MI]]). Only 7% of patients with SVT will have had a prior myocardial infarction (MI).  Wide complex tachycardia will be due to [[VT]] in 98% of cases if there's a history of structural heart disease.


====The Presence of AV Dissociation====
Differentiating between [[VT]] and [[SVT]] as the cause of wide complex tachycardia is absolutely critical because the treatment options are quite different for [[VT]] versus [[SVT]] with aberrancy.
Although AV dissociation is highly suggestive of VT, it may also be seen in [[junctional tachycardia]]s with retrograde block.


Example: Shown below is a wide complex tachycardia. [[AV dissociation]] is present as shown by the varying morphology highlighted by the red arrows. [[LBBB]] configuration. Absence of RS in the chest leads.  The diagnosis is [[VT]].
===Ventricular Tachycardia===
[[Image:wide_qrs_tachy_AAM3.png|center|700px]]
The diagnosis of [[VT]] is more likely if:
:*There is a history of [[myocardial infarction]], [[myocardial ischemia]], [[heart failure]] or [[structural heart disease]]
:*The [[electrical axis]] is -90 to -180 degrees (a “northwest” or “superior” axis)
:*The [[QRS]] is > 140 msec
:*There is [[AV dissociation]]
:*There are positive or negative [[QRS]] complexes in all the precordial leads
:*The morphology of the [[QRS]] complexes resembles that of a previous [[premature ventricular contraction]] ([[PVC]]).
:*'''''Hemodynamic stability does not reliably differentiate [[VT]] from [[SVT]]'''''. Patients with ventricular tachycardia can often be hemodynamically stable, and stable vital signs do not rule out ventricular tachycardia.  This is often a major mistake on the part of clinicians and can lead to inappropriate treatment of [[VT]] as [[SVT]] with poor outcomes. <ref name="pmid4057488">{{cite journal |author=Morady F, Baerman JM, DiCarlo LA, DeBuitleir M, Krol RB, Wahr DW |title=A prevalent misconception regarding wide-complex tachycardias |journal=[[JAMA : the Journal of the American Medical Association]] |volume=254 |issue=19 |pages=2790–2 |year=1985 |month=November |pmid=4057488 |doi= |url=http://jama.jamanetwork.com/article.aspx?volume=254&page=2790 |issn= |accessdate=2013-08-04}}</ref>


Example: Shown below is a wide complex tachycardia. [[AV dissociation]] is present as shown by the varying morphology highlighted by the red arrows.  LBBB configuration. Absence of RS in the chest leads. The diagnosis is [[VT]].
===Supraventricular Tachycardia with Aberrant Conduction===
[[Image:wide_qrs_tachy_AAM4.png|center|700px]]
The diagnosis of [[atrial fibrillation]] with aberrant conduction should be considered if


----
:*The heart rate is over 200 beats per minute
:*If the rhythm is grossly irregularly irregular


====Duration of the QRS Complex====
===Pre-Excitation===
* A wide complex tachycardia with a [[RBBB]] morphology and a QRS > 0.14, or a [[LBBB]] morphology with a QRS > 0.16 suggests [[VT]].
The diagnosis of rapid conduction down a [[bypass tract]] due to ventricular pre-excitation such as [[Wolff-Parkinson-White syndrome]] ([[WPW]]) should be considered if
 
====Morphology of the QRS Complexes====
* The finding of a positive or negative QRS complex in all precordial leads is in favor of [[ventricular tachycardia]].
* A monophasic or biphasic RBBB QRS complex in V1. But none of their patients with SVT had a preexisting RBBB. Therefore, this finding is of limited importance (A Wellens criterion).
* 80 to 85% of aberrant beats have a RBBB pattern, but ectopic beats that arise from the LV have a similar morphology.
* LBBB with a rightward axis
* LBBB with the following QRS morphology:
:* R wave in V1 or V2 > 0.03 second
:* Any Q wave in V6
:* Onset of the QRS to nadir of the S wave in V1 > 0.06 seconds
:* Notching of the S wave in V1 or V2
 
{| class="wikitable" width="500px"
! colspan="3" | Morphological criteria
|-
!colspan="3" |[[LBBB]] pattern
|-
| Initial R more than 40 ms? ||Yes ≥ VT || [[Image:Rhythm_RSratio.png|thumb|100px]]
|-
| Slurred or notched downwards leg of S wave in leads V1 or V2? || Yes ≥ [[VT]] ||
|-
| Beginning of Q to nadir QS > 60 ms in V1 or V2? || Yes ≥ [[VT]] || LR > 50:1
|-
| Q or QS in V6? || Yes ≥ [[VT]] || LR > 50:1
|-
| colspan="3" |[[Image:Rhythm_LBTBmorph_nl.png|thumb|300px]]
|-
! colspan="3" |[[RBBB]] pattern
|-
| Monofasic R or qR in V1? ||Yes ≥ [[VT]] ||
|-
| R taller than R' (rabbit-ear sign)?||Yes ≥ [[VT]] || LR > 50:1
|-
| rS in V6? || Yes ≥ VT || LR > 50:1
|-
|}
{{clr}}


----
:*There is intermittent present of a [[Delta wave]]
:*There is intermittently a short [[PR interval]]


====Morphology of Premature Beats During Sinus Rhythm====
===Paced Rhythms===
* If [[premature ventricular contractions]] ([[PVCs]]) are present on a prior tracing, and if the morphology of the wide complex tachycardia is the same, then it is likely to be ventricular tachycardia.
A paced rhythm as a cause of wide complex tachycardia is infrequent.  This diagnosis is suggested if
* Previous EKG may show a preexisting [[intraventricular conduction delay]] ([[IVCD]]) which would favor SVT with abberancy.
* If there are [[premature atrial contractions]] ([[PAC]])s with aberrant conduction, then the origin of the wide complex tachycardia may be supraventricular.


:Example: Shown below is a wide complex tachycardia. There is no AV dissociation. A [[RBBB]] morphology is present. The wide complex tachycardia resembles [[sinus rhythm]] from the same patient. The diagnosis in this patient is SVT with [[RBBB]]:
:*A pacemaker is in place and there is a [[LBBB]] pattern with superior left axis deviation, however, depending on the site of pacing this pattern can vary significantly
[[Image:wide_qrs_tachy_AAM1.jpg|center|700px]]
:*A wide complex tachycardia can be due to an SVT if the pacemaker is tracking sensed atrial activity and is pacing the ventricles rapidly as result
:*[[Pacemaker-mediated tachycardia]] may be present if there is retrograde conduction which triggers atrial activity during ventricular pacing.
:*[[Runaway pacemaker syndrome]] in which the pacemaker fires at a rate of nearly 2000 bpm and captures intermittently
:*[[Sensor induced tachycardia]] in which case the pacemaker fires at a rate of nearly 160-180 bpm in response to electrocautery, noise, vibration, limb movement or other stimuli.


:Shown below is the ECG from the same patient as above in sinus rhythm. The QRS complex is very similiar to that during the wide complex tachycardia:
===Other Conditions===
[[Image:wide_qrs_tachy_AAM2.jpg|center|700px]]
* [[ECG artifact]]
----
* [[Ventricular fibrillation]] is usually more chaotic


====The QRS Axis====
==Epidemiology and Demographics==
*A "northwest axis" with a [[QRS axis]] in the RUQ between -90 and +180 degrees favors [[ventricular tachycardia]].
The underlying cause of wide complex tachycardia tends to be [[ventricular tachycardia]] ([[VT]]) in patients > 35 years of age (sensitivity of 92% and a positive predictive value of 85% for VT) and [[supraventricular tachycardia]] ([[SVT]]) with aberrancy in patients <u><</u> 35 years of age (positive predictive value of approximately 70%).<ref name="pmid3800075">{{cite journal |author=Baerman JM, Morady F, DiCarlo LA, de Buitleir M |title=Differentiation of ventricular tachycardia from supraventricular tachycardia with aberration: value of the clinical history |journal=[[Annals of Emergency Medicine]] |volume=16 |issue=1 |pages=40–3 |year=1987 |month=January |pmid=3800075 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0196-0644(87)80283-4 |issn= |accessdate=2013-08-04}}</ref>


:The image below illustrates the "Northwest axis"also known as "Extreme Right Axis" or "No Man's Land":
==Risk Factors==
[[File:QRS axis.PNG|center|600px]]
Risk factors for the ventricular tachycardia as a cause of wide complex tachycardia include a history of prior [[myocardial infarction]], a history of [[congestive heart failure]], and a history of recent [[angina pectoris]].  These three historical features have [[positive predictive values]] for [[VT]] of > 95% in a small study, but sensitivities of 66%, 24%, and 24%, respectively.<ref name="pmid3800075">{{cite journal |author=Baerman JM, Morady F, DiCarlo LA, de Buitleir M |title=Differentiation of ventricular tachycardia from supraventricular tachycardia with aberration: value of the clinical history |journal=[[Annals of Emergency Medicine]] |volume=16 |issue=1 |pages=40–3 |year=1987 |month=January |pmid=3800075 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0196-0644(87)80283-4 |issn= |accessdate=2013-08-04}}</ref>  Wide complex tachycardia will be due to [[VT]] in 98% of cases if there's a history of [[structural heart disease]].  Only 7% of patients with [[SVT]] with aberrancy will have had a prior [[myocardial infarction]] ([[MI]]).


====Capture Beats====
==Electrocardiogram==
* Rare, but one of the strongest pieces of evidence in favor of VT.
Wide complex tachycardia is defined as a heart rate > 100 beats per minute and a [[QRS duration]] > 120 ms.
* SVT with aberrancy rarely follows a beat with a short cycle length.


====Fusion Beats====
===Case 1===
:[[Fusion beats]] are rare, but strongly suggests VT.
VT with right bundle branch block morphology: [[AV dissociation]] is present, the [[QRS interval]] is greater than 140 ms, and the complexes are all up right in the anterior precordial leads consistent with [[ventricular tachycardia]] as the origin of the rhythm.
[[File:VT with fusion beats.jpg|center|800px]]
[[File:VT with RBBB morphology.jpg|center|800px]]


----
----
===Case 2:===
Shown below is a patient with sinus tachycardia and [[WPW]] which mimics VT: A [[Delta wave]] consistent with pre-excitation is present.


====Vagal Manuevers====
[[File:WPW with sinus tachycardia mimicking VT.jpg|center|800px]]
* VT is generally not affected by vagal stimulation.
* May terminate reentrant arrhythmias


====Atrial Pacing====
==Laboratory Studies==
* A pacing wire is placed in the RA and the atrium is stimulated at a rate faster than the tachycardia.
[[Electroyte abnormalities]] such as [[hypokalemia]] (which can be associated with [[ventricular tachycardia]]), and [[hypomagnesemia]] (which can lead to [[Torsade de Pointes]]) should be ruled out.
* If ventricular capture occurs and the QRS is normal in duration, then one can exclude the possibility of aberrant conduction.


====Onset of the Tachycardia====
==Medical Therapy==
* Diagnosis of SVT made if the episode is initiated by a premature P wave.
The management of wide complex tachycardia should begin by assessing the patient's ABCs (airway, breathing, and circulation). If the patient is unstable and either [[hypotension]], [[altered mental status]], [[chest pain]], [[heart failure]] or [[seizures]] are present, then immediate synchronized [[cardioversion]] should be performed. If the patient is stable, the optimal management depends upon the differentiation of [[ventricular tachycardia]] versus [[supraventricular tachycardia]] with aberrant conduction as a cause of the wide complex tachycardia.  Treatment targeted at the underlying cause can then be initiated.  '''A wide complex tachycardia should be assumed to be and managed as though it is due to ventricular tachycardia until proven otherwise.  This is true even in a hemodynamically stable patient until proven otherwise (VT can often be hemodynamically stable).  The initial management strategy includes avoiding the use of a long acting [[AV nodal blocking agent]] and drugs that suppress [[left ventricular contractility]] such as [[verapamil]] which can induce [[hypotension]] in a previously stable patient.'''
* If the paroxysm begins with a QRS then the tachycardia may be either ventricular or junctional in origin.
* If the first QRS of the tachycardia is preceded by a sinus p wave with a PR interval shorter than that of the conducted sinus beats, the tachycardia is ventricular.


====His Bundle Recording====
* In SVT, each QRS is preceded by a His bundle potential.
* In VT there is no preceding His deflection.
* The retrograde His deflection is usually obscured by the much larger QRS complex.


====Regularity of the Rhythm====
{{familytree/start |summary=PE diagnosis Algorithm.}}
=====Regular=====
{{familytree | | | | | | | | | | | | | | | A01 | | | | | A01='''Wide complex tachycardia'''<br>[[QRS]] ≥ 120ms}}
* VT (slight irregularity of RR)
{{familytree | | | | | | | | | | | | | | | |!| | | | | | | }}
* SVT with aberrancy: Sinus, atrial tachycardia (AT), or flutter
{{familytree | | | | | | | | | | | | | | | A02 | | | | | A02='''Do the following simultaneously:'''<br><br>- Assess and support ABC's as needed<br>- Give [[oxygen therapy|oxygen]]<br>- Monitor [[ECG]], [[BP]], [[oxygen saturation|oxymetry]]<br>- Identify and treat reversible causes ([[hypokalemia]], [[hypomagnesemia]]}}
* Antidromic atrioventricular reentrant tachycardia (AVRT)
{{familytree | | | | | | | | | | | | | | | |!| | | | | | | }}
 
{{familytree | | | | | | | | | | | | | | | A03 | | | | | | A03='''Is the patient stable?'''<br><br>Unstable signs include:<br>- [[Chest pain]]<br>- [[Congestive heart failure]]<br>- [[Hypotension]]<br>- [[Loss of consciousness]]<br>- [[Seizures]]}}
=====Irregular=====
{{familytree | | | | | | | | |,|-|-|-|-|-|-|^|-|-|-|-|-|-|-|.| | | | | | }}
* The first 50 beats of VT can be irregular
{{familytree | | | | | | | | B01 | | | | | | | | | | | | | B02 | | | B01=Yes|B02=No}}
* SVT with aberrancy: [[Atrial fibrillation]], multifocal atrial tachycardia (MAT)
{{familytree | | | | | | | | |!| | | | | | | | | | | | | | |!| | | | }}
* [[Atrial fibrillation]] with bypass tract usch as [[WPW]] is a dangerous cause of a very rapid irregular rhythm as the atrial rate is conducted rapidly over the bypass tract. Shown below is the tracing of a patient with [[atrial fibrillation]] conducting down the bypass tract in [[WPW]]. Note that the rate is extremely rapid, and the rhythm is irregularly irregular.  It is critical that this rhythm be recognized to avoid the administration of agents that would further accelerate conduction down the accessory pathway in this patient with [[WPW]] which could cause degeneration into [[ventricular fibrillation]]. The best treatment for this patient is [[Pronestyl]] 15 mg/kg load over 30 minutes then 2-6 mg/min gtt or DC [[cardioversion]]:
{{familytree | | | | | | | | C01 | | | | | | | | | | | | | C02 | | | C01='''Is the rhythm regular?'''|C02='''Immediate synchronized [[cardioversion]]'''<br><br>-Establish IV access<br>- Give IV [[sedation]] if the patient is conscious<br>- Consider expert consultation}}
 
{{familytree | | | | | | |,|-|^|-|-|-|-|-|-|-|-|-|.| | | | }}
[[File:Wpw with afib.PNG|center|500px]]
{{familytree | | | | | | D01 | | | | | | | | | | D02 | | | D01='''Regular rhythm'''| D02='''Irregular rhythm'''}}
----
{{familytree | | | | |,|-|^|-|.| | | |,|-|-|-|v|-|^|-|v|-|-|-|.| |}}
* The mechanism of SVT with aberrancy is usually concealed retrograde conduction.  The ventricular beat penetrates the right branch (RB) or left branch (LB).  When the next supraventricular activation front occurs that bundle is refractory and if conduction can occur, it will proceed down the other bundle.  Since the RB has a longer refractory period than the LB, a right bundle branch block (RBBB) morphology is more common.
{{familytree | | | | E01 | | E02 | | E03 | | E04 | | E05 | | E06 | E01='''[[Ventricular tachycardia]] or uncertain rhythm?'''|E02='''Confirmed [[SVT]] with aberrancy?'''|E03='''[[Afib]] with aberrancy?'''|E04='''Pre-excited [[Afib]] ([[Afib]] + [[WPW]])?'''|E05='''Recurrent polymorphic [[VT]]?'''|E06='''[[Torsade de pointes]]?'''}}
* Other mechanisms of “rate related aberrancy” are preexisting bundle branch block (BBB), physiologic (phase 3) aberration and use dependent aberration secondary to medication. In physiologic aberration, the stimulus comes to the His-Purkinje system before it has fully recovered from the previous stimulus.  The ensuing activation is either blocked or conducts slowly.  Again, the RB is the one more at risk.  Most commonly seen at the onset of paroxysmal supraventricular tachycardia (PSVT), but can become sustained.
{{familytree | | | | |!| | | |!| | | |!| | | |!| | | |!| | | |!| | }}
* In use-dependent aberration, a patient on and anti-arrhythmic (especially class Ic agents) will have a progressive decrement in ventricular conduction rate the more it is stimulated.  During faster heart rates, less time is available for the drug to dissociate from the receptor and an increased number of receptors are blocked.
{{familytree | | | | F01 | | F02 | | F03 | | F04 | | F05 | | F06 | F01=- Give [[amiodarone]] 150 mg IV over 10 min<br><br>- Repeat [[amiodarone]] as needed for a maximal dose of 2.2g/24h<br><br>- Prepare for elective synchronized [[cardioversion]]| F02=- If '''certain''' [[VT]] is '''not''' present, give [[adenosine]] 6 mg rapid IV push<br><br>- If no [[conversion]] give 12 mg IV push<br><br>- May repeat 12 mg dose once| F03=- Consider expert consultation<br><br>- Control rate e.g [[diltiazem]] or [[beta blocker]]s<br>Use [[beta blocker]]s with caution in [[pulmonary disease]]s or [[CHF]]| F04= - Consider expert consultation<br><br>- Avoid AV nodal blocking agents<br>e.g [[adenosine]], [[digoxin]], [[diltiazem]] and [[verapamil]]<br><br>- Consider [[amiodarone]] 150 mg IV over 10 min| F05= Consider expert consultation| F06=Load with [[Magnesium]] 1-2 g over 5-60 min, then infusion}}
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===Sophisticated Electrophysiologic Criteria===
Several [[ECG]] criteria and algorithms have been used to differentiate [[VT]] and [[SVT]], the common one of which is Brugada algorithm. Below is a list of all algorithms:
* Brugada algorithm: sensitivity 89%, specificity 59.2%<ref name="pmid2022022">{{cite journal| author=Brugada P, Brugada J, Mont L, Smeets J, Andries EW| title=A new approach to the differential diagnosis of a regular tachycardia with a wide QRS complex. | journal=Circulation | year= 1991 | volume= 83 | issue= 5 | pages= 1649-59 | pmid=2022022 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2022022  }} </ref>
 
* The lead II R-wave-peak-time: sensitivity 60%, specificity 82.7%<ref name="pmid20215043">{{cite journal| author=Pava LF, Perafán P, Badiel M, Arango JJ, Mont L, Morillo CA et al.| title=R-wave peak time at DII: a new criterion for differentiating between wide complex QRS tachycardias. | journal=Heart Rhythm | year= 2010 | volume= 7 | issue= 7 | pages= 922-6 | pmid=20215043 | doi=10.1016/j.hrthm.2010.03.001 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20215043  }} </ref>
 
* The aVR algorithm: sensitivity 87.1%, specificity 48%<ref name="pmid17272358">{{cite journal| author=Vereckei A, Duray G, Szénási G, Altemose GT, Miller JM| title=Application of a new algorithm in the differential diagnosis of wide QRS complex tachycardia. | journal=Eur Heart J | year= 2007 | volume= 28 | issue= 5 | pages= 589-600 | pmid=17272358 | doi=10.1093/eurheartj/ehl473 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17272358  }} </ref>
 
* The Bayesian algorithm: sensitivity 89%, specificity 52%<ref name="pmid11060873">{{cite journal| author=Lau EW, Pathamanathan RK, Ng GA, Cooper J, Skehan JD, Griffith MJ| title=The Bayesian approach improves the electrocardiographic diagnosis of broad complex tachycardia. | journal=Pacing Clin Electrophysiol | year= 2000 | volume= 23 | issue= 10 Pt 1 | pages= 1519-26 | pmid=11060873 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11060873  }} </ref>
 
* The Griffith algorithm: sensitivity 94.2%, specificity 39.8%<ref name="pmid7905552">{{cite journal| author=Griffith MJ, Garratt CJ, Mounsey P, Camm AJ| title=Ventricular tachycardia as default diagnosis in broad complex tachycardia. | journal=Lancet | year= 1994 | volume= 343 | issue= 8894 | pages= 386-8 | pmid=7905552 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7905552  }} </ref>
====The R Wave Peak Time====
In 2010 Joseph Brugada et al. published a new criterion to differentiate VT from SVT in wide complex tachycardias: the R wave peak time (RWPT) in Lead II.<ref name="pmid20215043">{{cite journal |author=Pava LF, Perafán P, Badiel M, Arango JJ, Mont L, Morillo CA, Brugada J |title=R-wave peak time at DII: a new criterion for differentiating between wide complex QRS tachycardias |journal=[[Heart Rhythm : the Official Journal of the Heart Rhythm Society]] |volume=7 |issue=7 |pages=922–6 |year=2010 |month=July |pmid=20215043 |doi=10.1016/j.hrthm.2010.03.001 |url=http://linkinghub.elsevier.com/retrieve/pii/S1547-5271(10)00216-X |issn= |accessdate=2012-10-13}}</ref> To aplly the criteria, the duration of onset of the QRS to the first change in polarity (either nadir Q or peak R) is measured in lead II as shown below.  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.
 
Example: As shown below, an R-wave to Peak Time (RWPT) of ≥ 50ms in lead II strongly suggests VT:
[[File:RWPT.png|center|500px]]
 
====Brugada Criteria====
{{familytree/start}}
{{familytree | | | | | | A01 |-|-|-|-|-| A02 |A01=Absence of an RS complex<br> in all precordial leads?|A02='''Yes?'''<br><br>'''VT''' (SN=0.21  SP=1.0)}}
{{familytree | | | | | | |!| | | | | | | | | }}
{{familytree |border=0| | | | | | B01 | | | | |B01='''No?'''}}
{{familytree | | | | | | |!| | | | | | | | | | }}
{{familytree | | | | | | C01 |-|-|-|-|-| C02 |C01=R to S interval>100 ms in <br>one precordial lead?|C02='''Yes?'''<br><br>'''VT''' (SN=0.21  SP=1.0)}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree |border=0| | | | | | D01 | | | | | | | | | | | | |D01='''No?'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree | | | | | | E01 |-|-|-|-|-| E02 | | |E01=AV dissociation?|E02='''Yes?'''<br><br>'''VT''' (SN=0.82  SP=0.98)}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree |border=0| | | | | | F01 | | | | | | | | | | | | |F01='''No?'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree | | | | | | G01 |-|-|-|-|-| G02 | | |G01=Morphology criteria for VT present<br> both in precordial leads V1, V2 and V6?|G02='''Yes?'''<br><br>'''VT''' (SN=0.987  SP=0.965)}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree |border=0| | | | | | H01 | | | | | | | | | | | | |H01='''No?'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree | | | | | | I01 | | | | | | | | | | | | |I01='''SVT''' (SN=0.965  SP=0.987)}}
{{familytree/end}}
{{familytree/end}}


====Vereckei Criteria====
''Algorithm based on the 2003 [[ACLS]] guidelines for the management of tachycardia.''<ref name="pmid14563598">{{cite journal| author=Blomström-Lundqvist C, Scheinman MM, Aliot EM, Alpert JS, Calkins H, Camm AJ et al.| title=ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias--executive summary. a report of the American college of cardiology/American heart association task force on practice guidelines and the European society of cardiology committee for practice guidelines (writing committee to develop guidelines for the management of patients with supraventricular arrhythmias) developed in collaboration with NASPE-Heart Rhythm Society. | journal=J Am Coll Cardiol | year= 2003 | volume= 42 | issue= 8 | pages= 1493-531 | pmid=14563598 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=14563598  }} </ref>
* An algorithm has been proposed by Vereckei and colleagues, wherein in addition to do the traditional criteria, the voltage change on the EKG is used as a final discriminatory criteria.
* In this method, the voltage change during the initial 40 ms (V<sub>i</sub>) and the terminal 40 ms (V<sub>t</sub>) of the same QRS complex is used to estimate the (V<sub>i</sub>) and terminal (V<sub>t</sub>) ventricular activation velocity ratio (V<sub>i</sub>/V<sub>t</sub>).
* A V<sub>i</sub>/V<sub>t</sub> > 1 suggests SVT and a V<sub>i</sub>/V<sub>t</sub> ≤ 1 suggests VT.<ref name="pmid17272358">{{cite journal |author=Vereckei A, Duray G, Szénási G, Altemose GT, Miller JM |title=Application of a new algorithm in the differential diagnosis of wide QRS complex tachycardia |journal=[[European Heart Journal]] |volume=28 |issue=5 |pages=589–600 |year=2007 |month=March |pmid=17272358 |doi=10.1093/eurheartj/ehl473 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17272358 |issn= |accessdate=2012-10-13}}</ref>
 
 
{{familytree/start}}
{{familytree | | | | | | A01 |-|-|-|-|-| A02 |A01=AV dissociation present?|A02='''Yes?'''<br><br>'''VT'''}}
{{familytree | | | | | | |!| | | | | | | | | }}
{{familytree |border=0| | | | | | B01 | | | | |B01='''No?'''}}
{{familytree | | | | | | |!| | | | | | | | | | }}
{{familytree | | | | | | C01 |-|-|-|-|-| C02 |C01=Initial R wave in aVR present?|C02='''Yes?'''<br><br>'''VT'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree |border=0| | | | | | D01 | | | | | | | | | | | | |D01='''No?'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree | | | | | | E01 |-|-|-|-|-| E02 | | |E01=QRS morphology unlike BBB or FB|E02='''Yes?'''<br><br>'''VT'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree |border=0| | | | | | F01 | | | | | | | | | | | | |F01='''No?'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree | | | | | | G01 |-|-|-|-|-| G02 | | |G01=V<sub>i</sub>/V<sub>t</sub>≤1?|G02='''Yes?'''<br><br>'''VT'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree |border=0| | | | | | H01 | | | | | | | | | | | | |H01='''No?'''}}
{{familytree | | | | | | |!| | | | | | | | | | | | | | }}
{{familytree | | | | | | I01 | | | | | | | | | | | | |I01='''SVT'''}}
{{familytree/end}}
 
=====Calculation of V<sub>i</sub>/V<sub>t</sub>=====
Shown below is an image demonstrating the method used to calculate Vi/Vt. In this tracing, Vi/Vt is < 1 is suggestive of [[ventricular tachycardia]] according to Vereckei criteria.
 
[[File:Vivt.png|350px]]
----
 
===Putting it all together: The ACC Algorithm===
{{familytree/start}}
{{familytree | | | | | | | | | | | | | | | | | A01 | | | | | |A01='''Wide QRS complex tachycardia'''<br>(QRS duration greater than 120 ms)}}
{{familytree | | | | | | | | | | | | | | | | | |!| | | | | | | | }}
{{familytree | | | | | | | | | | | | | | | | | B01 | | | | | |B01=Regular or irregular?}}
{{familytree | | | | | | | | | | |,|-|-|-|-|-|-|^|-|-|-|-|-|-|.| }}
{{familytree | | | | | | | | | | C01 | | | | | | | | | | | | C02 |C01=Regular|C02=Irregular}}
{{familytree | | | | | | | | | | |!| | | | | | | | | | | | | |!| }}
{{familytree | | | | | | | | | | |)|-| D01 | | | | | | | | | D02 |D01=Is QRS identical to that during SR?<br>If yes, consider:<br> '''- SVT and BBB<br> - Antidromic AVRT'''|D02='''Atrial fibrillation<br>Atrial flutter / AT with variable<br> conduction and:<br>a) BBB or<br>b) Antegrade conduction via AP'''}}
{{familytree | | | | | | | E01 |-|(| | | | | | | | | | | | | |E01=Vagal maneuvers or<br>adenosine}}
{{familytree | | | | | | | | | | |)|-| E02 | | | | | | | | | |E02=Previous myocardial infarction or structural heart disease? If yes, '''VT''' is likely.}}
{{familytree | | | | | | | | | | |!| | | | | | | | | | | | | | | }}
{{familytree | | | | | | | | | | F01 | | | | | | | | | | | | | |F01=1 to 1 AV relationship?}}
{{familytree | | | | | |,|-|-|-|-|^|-|-|-|-|-|-|-|-|.| | | | | | }}
{{familytree | | | | | G01 | | | | | | | | | | | | G02 | | | | | G01= Yes or unknown| G02= No}}
{{familytree | | | | | |!| | | | | | | | | | | | | |!| | | | | | }}
{{familytree | | | | | |!| | | | | | | | | | | |,|-|^|-|.| | | | }}
{{familytree | | | | | |!| | | | | | | | | | | H01 | | H02 | | |H01= V rate faster than A rate|H02=A rate faster than V rate}}
{{familytree | | | | | |!| | | | | | | | | | | |!| | | |!| | | | }}
{{familytree | | | | | I01 | | | | | | | | | | H03 | | H04 | | | I01=QRS morphology in precordial leads| H03='''VT'''|H04='''Atrial tachycardia'''<br>'''Atrial flutter'''}}
{{familytree | |,|-|-|-|+|-|-|-|v|-|-|-|.| | | | | | | | | | | | }}
{{familytree | |!| | | |!| | | |!| | | |!| | | | | | | | | | | | }}
{{familytree | J01 | | J02 | | J03 | | J04 | | | | | | | | | | | J01= Typical RBBB <br> or LBBB| J02=Precordial leads:<br>- Concordant<br>- No R/S pattern<br>- Onset of R to nadir longer than 100ms<br>| J03=RBBB pattern:<br>- qR, Rs or Rr' in V1<br>- Frontal plane axis range<br>from +90 degrees to -90 degrees<br>| J04=LBBB pattern:<br> - R in V1 longer than 30 ms<br>- R to nadir of S in V1 greater than 60 ms<br>- qR or qS in V6}}
{{familytree | |!| | | |!| | | |!| | | |!| | | | | | | | | | | | }}
{{familytree | K01 | | K02 | | K03 | | K04 | | | | | | | | | | |K01= '''SVT'''|K02='''VT'''|K03='''VT'''|K04='''VT'''}}
{{familytree/end}}
 
 
''The above algorithm is adapted from the American College of Cardiology.''


==References==
==References==

Latest revision as of 16:01, 10 August 2013
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Wide complex tachycardia Microchapters

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Electrocardiogram

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Wide complex tachycardia is a cardiac rhythm of more than 100 beats per minute with a QRS duration of 120 milliseconds or more. It is critical to differentiate whether the wide complex tachycardia is of ventricular origin and is ventricular tachycardia (VT), or if it is of supraventricular origin with aberrant conduction (SVT with aberrancy). Rapid differentiation between these two causes of wide complex tachycardia is absolutely critical because the treatment options are quite different for VT versus SVT with aberrancy. Wide complex tachycardia should be assumed to be due to ventricular tachycardia even in a hemodynamically stable patient unless proven otherwise, and first line treatment with verapamil should be avoided.

Causes

A wide complex tachycardia is either of ventricular origin (ventricular tachycardia or VT), of supraventricular origin with aberrant conduction (SVT with aberrancy), of supraventricular origin and is conducted down a bypass tract such as in Wolff-Parkinson-White syndrome (WPW), or is due to a pacemaker malfunction. Approximately 80% of wide complex tachycardias are due to ventricular tachycardia.[1]

Differential Diagnosis of Wide Complex Tachycardia: Distinguishing VT from SVT

For more detailed information regarding how to differentiate VT from SVT please view the differential diagnosis page or click here.

Differentiating between VT and SVT as the cause of wide complex tachycardia is absolutely critical because the treatment options are quite different for VT versus SVT with aberrancy.

Ventricular Tachycardia

The diagnosis of VT is more likely if:

Supraventricular Tachycardia with Aberrant Conduction

The diagnosis of atrial fibrillation with aberrant conduction should be considered if

  • The heart rate is over 200 beats per minute
  • If the rhythm is grossly irregularly irregular

Pre-Excitation

The diagnosis of rapid conduction down a bypass tract due to ventricular pre-excitation such as Wolff-Parkinson-White syndrome (WPW) should be considered if

Paced Rhythms

A paced rhythm as a cause of wide complex tachycardia is infrequent. This diagnosis is suggested if

  • A pacemaker is in place and there is a LBBB pattern with superior left axis deviation, however, depending on the site of pacing this pattern can vary significantly
  • A wide complex tachycardia can be due to an SVT if the pacemaker is tracking sensed atrial activity and is pacing the ventricles rapidly as result
  • Pacemaker-mediated tachycardia may be present if there is retrograde conduction which triggers atrial activity during ventricular pacing.
  • Runaway pacemaker syndrome in which the pacemaker fires at a rate of nearly 2000 bpm and captures intermittently
  • Sensor induced tachycardia in which case the pacemaker fires at a rate of nearly 160-180 bpm in response to electrocautery, noise, vibration, limb movement or other stimuli.

Other Conditions

Epidemiology and Demographics

The underlying cause of wide complex tachycardia tends to be ventricular tachycardia (VT) in patients > 35 years of age (sensitivity of 92% and a positive predictive value of 85% for VT) and supraventricular tachycardia (SVT) with aberrancy in patients < 35 years of age (positive predictive value of approximately 70%).[3]

Risk Factors

Risk factors for the ventricular tachycardia as a cause of wide complex tachycardia include a history of prior myocardial infarction, a history of congestive heart failure, and a history of recent angina pectoris. These three historical features have positive predictive values for VT of > 95% in a small study, but sensitivities of 66%, 24%, and 24%, respectively.[3] Wide complex tachycardia will be due to VT in 98% of cases if there's a history of structural heart disease. Only 7% of patients with SVT with aberrancy will have had a prior myocardial infarction (MI).

Electrocardiogram

Wide complex tachycardia is defined as a heart rate > 100 beats per minute and a QRS duration > 120 ms.

Case 1

VT with right bundle branch block morphology: AV dissociation is present, the QRS interval is greater than 140 ms, and the complexes are all up right in the anterior precordial leads consistent with ventricular tachycardia as the origin of the rhythm.

Case 2:

Shown below is a patient with sinus tachycardia and WPW which mimics VT: A Delta wave consistent with pre-excitation is present.

Laboratory Studies

Electroyte abnormalities such as hypokalemia (which can be associated with ventricular tachycardia), and hypomagnesemia (which can lead to Torsade de Pointes) should be ruled out.

Medical Therapy

The management of wide complex tachycardia should begin by assessing the patient's ABCs (airway, breathing, and circulation). If the patient is unstable and either hypotension, altered mental status, chest pain, heart failure or seizures are present, then immediate synchronized cardioversion should be performed. If the patient is stable, the optimal management depends upon the differentiation of ventricular tachycardia versus supraventricular tachycardia with aberrant conduction as a cause of the wide complex tachycardia. Treatment targeted at the underlying cause can then be initiated. A wide complex tachycardia should be assumed to be and managed as though it is due to ventricular tachycardia until proven otherwise. This is true even in a hemodynamically stable patient until proven otherwise (VT can often be hemodynamically stable). The initial management strategy includes avoiding the use of a long acting AV nodal blocking agent and drugs that suppress left ventricular contractility such as verapamil which can induce hypotension in a previously stable patient.


 
 
 
 
 
 
 
 
 
 
 
 
 
 
Wide complex tachycardia
QRS ≥ 120ms
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Do the following simultaneously:

- Assess and support ABC's as needed
- Give oxygen
- Monitor ECG, BP, oxymetry
- Identify and treat reversible causes (hypokalemia, hypomagnesemia
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Is the patient stable?

Unstable signs include:
- Chest pain
- Congestive heart failure
- Hypotension
- Loss of consciousness
- Seizures
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
 
 
 
 
 
 
 
 
 
 
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Is the rhythm regular?
 
 
 
 
 
 
 
 
 
 
 
 
Immediate synchronized cardioversion

-Establish IV access
- Give IV sedation if the patient is conscious
- Consider expert consultation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Regular rhythm
 
 
 
 
 
 
 
 
 
Irregular rhythm
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Ventricular tachycardia or uncertain rhythm?
 
Confirmed SVT with aberrancy?
 
Afib with aberrancy?
 
Pre-excited Afib (Afib + WPW)?
 
Recurrent polymorphic VT?
 
Torsade de pointes?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
- Give amiodarone 150 mg IV over 10 min

- Repeat amiodarone as needed for a maximal dose of 2.2g/24h

- Prepare for elective synchronized cardioversion
 
- If certain VT is not present, give adenosine 6 mg rapid IV push

- If no conversion give 12 mg IV push

- May repeat 12 mg dose once
 
- Consider expert consultation

- Control rate e.g diltiazem or beta blockers
Use beta blockers with caution in pulmonary diseases or CHF
 
- Consider expert consultation

- Avoid AV nodal blocking agents
e.g adenosine, digoxin, diltiazem and verapamil

- Consider amiodarone 150 mg IV over 10 min
 
Consider expert consultation
 
Load with Magnesium 1-2 g over 5-60 min, then infusion

Algorithm based on the 2003 ACLS guidelines for the management of tachycardia.[4]

References

  1. ↑ Lam P, Saba S (2002). "Approach to the evaluation and management of wide complex tachycardias". Indian Pacing and Electrophysiology Journal. 2 (4): 120–6. PMC 1557420. PMID 16951728. Retrieved 2013-08-04.
  2. ↑ Morady F, Baerman JM, DiCarlo LA, DeBuitleir M, Krol RB, Wahr DW (1985). "A prevalent misconception regarding wide-complex tachycardias". JAMA : the Journal of the American Medical Association. 254 (19): 2790–2. PMID 4057488. Retrieved 2013-08-04. Unknown parameter |month= ignored (help)
  3. ↑ 3.0 3.1 Baerman JM, Morady F, DiCarlo LA, de Buitleir M (1987). "Differentiation of ventricular tachycardia from supraventricular tachycardia with aberration: value of the clinical history". Annals of Emergency Medicine. 16 (1): 40–3. PMID 3800075. Retrieved 2013-08-04. Unknown parameter |month= ignored (help)
  4. ↑ Blomström-Lundqvist C, Scheinman MM, Aliot EM, Alpert JS, Calkins H, Camm AJ; et al. (2003). "ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias--executive summary. a report of the American college of cardiology/American heart association task force on practice guidelines and the European society of cardiology committee for practice guidelines (writing committee to develop guidelines for the management of patients with supraventricular arrhythmias) developed in collaboration with NASPE-Heart Rhythm Society". J Am Coll Cardiol. 42 (8): 1493–531. PMID 14563598.

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