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| __NOTOC__ | | __NOTOC__ |
| | {| class="infobox" style="float:right;" |
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| | | [[File:Siren.gif|30px|link=Wide complex tachycardia resident survival guide]]|| <br> || <br> |
| | | [[Wide complex tachycardia resident survival guide|'''Resident'''<br>'''Survival'''<br>'''Guide''']] |
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| | {| class="infobox" style="float:right;" |
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| | | [[File:Physician_Extender_Algorithms.gif|88px|link=Wide complex tachycardia physician extender algorithm]]|| <br> || <br> |
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| {{Wide complex tachycardia}} | | {{Wide complex tachycardia}} |
| {{CMG}} | | {{CMG}} |
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| {{SK}} WCT; fast and wide; wide and fast; wide-complex tachycardia; wide complex rhythm; SVT with aberrancy; SVT with aberrant conduction; supraventricular tachycardia with aberrancy; VT versus SVT
| | '''For patient information, click [[Wide complex tachycardia (patient information)|here]]''' |
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| ==Algorithms to Distinguish VT from SVT==
| | {{SK}} WCT, fast and wide, wide and fast, wide-complex tachycardia, wide complex rhythm, SVT with aberrancy, SVT with aberrant conduction, supraventricular tachycardia with aberrancy, VT versus SVT, broad complex tachycardia |
| ===Brugada Criteria===
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| [[File:Brugada algorithm.png|center]]
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| ===Vereckei Criteria=== | | ==[[Wide complex tachycardia overview|Overview]]== |
| An algorithm has been proposed by Vereckei and colleagues. In addition to 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(i)) and the terminal 40 ms (v(t)) of the same QRS complex is used to estimate the (v(i)) and terminal (v(t)) ventricular activation velocity ratio (v(i)/v(t)). A v(i)/v(t) >1 suggests SVT and a v(i)/v(t) <or=1 suggests VT.
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| <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>
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| [[File:Vereckei algorithm.png|center]] | | ==[[Wide complex tachycardia causes|Causes]]== |
| The method calculating Vi / Vt is shown below. Because the Vi/Vt si < 1, a diagnosis of VT is suggested by the tracing:
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| [[File:Vivt.png|center]] | | ==[[Wide complex tachycardia differential diagnosis|Differentiating VT from SVT as a Cause of Wide Complex Tachycardia]]== |
| ----
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| ===ACC Algorithm for Distinguishing SVT from VT=== | | ==[[Wide complex tachycardia epidemiology and demographics|Epidemiology and Demographics]]== |
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| [[File:Wide complex tachycardia algorithm.png|center|ACC algorithm]] | | ==[[Wide complex tachycardia risk factors|Risk Factors]]== |
| The above figure is adapted from the American College of Cardiology algorithm.
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| | ==[[Wide complex tachycardia natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| ==Diagnosis== | | ==Diagnosis== |
| === History===
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| The patient should be asked about drugs that are associated with ventricular tachycardia and if there is a history of ischemic heart disease which would dramatically increase the odds that the rhythm is VT. Wide complex tachycardia will be due to [[VT]] in 80% of cases and will be due to [[VT]] in 98% of cases if there's a history of either [[acute MI]] or structural heart disease. Only 7% of patients with SVT will have had a prior myocardial infarction (MI). VT or an accelerated idioventricular rhythm can be seen following reperfusion in STEMI. Digoxin, antiarrhythmics, phenothiazines, TCAs, and pheochromocytoma may also cause VT. Recent procedures such as cardiac catheterization, DC countershock, repair of congenital lesions are all associated iwth VT. A family history of [[sudden cardiac death]], a history of a [[channelopathy]] associated with [[arrhythmias]], and the hereditary [[Long QT syndrome]], and [[Brugada syndrome]] are all associated with VT.
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| ===Symptoms ===
| | [[Wide complex tachycardia history and symptoms|History and Symptoms]] | [[Wide complex tachycardia physical examination|Physical Examination]] | [[Wide complex tachycardia laboratory findings|Laboratory Findings]] | [[Wide complex tachycardia electrocardiogram|Electrocardiogram]] |
| *[[Shortness of breath]]
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| *[[Syncope]]
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| *[[Sudden cardiac death]] would suggest a diagnosis of [[ventricular tachycardia]]
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| === Physical Examination ===
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| * Vitals should be obtained to assess hemodynamic stability and guide therapy
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| * [[Cannon-a waves]] are a manifestation of [[AV dissociation]] and suggest VT
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| * [[Carotid sinus massage]] (CSM)/Valsalva: ST can gradually slow. MAT, AT, Flutter, and AF may transiently slow. An AV nodal dependent WCT may terminate. AV dissociation may become more apparent with CSM in VT. VT can terminate with CSM
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| ==Electrocardiogram==
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| EKG examples and diagnosis [[Wide complex tachycardias examples|here]]:
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| * Extreme axis deviation favors VT. Especially -90 to -180 or “northwest” or “superior” axis. (23% of SVT will have SAD)
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| * QRS duration >140 msec favors VT (21% of VT will have QRS <140 msec)
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| * AV dissociation is demonstrated in only 21% of VT
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| * Morphologic Criteria
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| *:* 4% of SVT and 6% of VT did not fulfill criteria in any lead
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| *:* 40% will have discordance between V1/V2 and V5/V6. One lead may suggest VT while another suggests SVT.
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| * An algorithmic approach was proposed by Brugada in 1991. It has a reported sensitivity of 99% and specificity of 97%.
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| {| class="wikitable" font-size="75%"
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| |- style="text-align:center;background-color:#6EB4EB;"
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| |+'''An overview of ventricular tachycardias''', follow the [[media:wideQRS_tachycardia_flow.png|wide complex tachycardia flowchart]]
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| !
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| !example
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| !regularity
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| !atrial frequency
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| !ventricular frequency
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| !origin (SVT/VT)
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| !p-wave
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| !effect of adenosine
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| |-
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| | colspan="8" style="text-align:left;background-color:#cfefcf;" | '''Wide complex (QRS>0.12)''' | |
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| ! [[Ventricular Tachycardia]]
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| | [[Image:vt_small.svg|200px]] | |
| | regular (mostly)
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| | 60-100 bpm
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| | 110-250 bpm
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| | ventricle (VT)
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| | [[AV-dissociation]]
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| | no rate reduction (sometimes accelerates)
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| |-
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| ! [[Ventricular Fibrillation]]
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| | [[Image:vf_small.svg|200px]]
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| | irregular
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| | 60-100 bpm
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| | 400-600 bpm
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| | ventricle (VT)
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| | [[AV-dissociation]]
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| | none
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| |-
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| ! [[Ventricular Flutter]]
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| | [[Image:vflutt_small.svg|200px]]
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| | regular
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| | 60-100 bpm
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| | 150-300 bpm
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| | ventricle (VT)
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| | [[AV-dissociation]]
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| | none
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| |-
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| ! [[Accelerated Idioventricular Rhythm]]
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| | [[Image:aivr_small.svg|200px]]
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| | regular (mostly)
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| | 60-100 bpm
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| | 50-110 bpm
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| | ventricle (VT)
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| | [[AV-dissociation]]
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| | no rate reduction (sometimes accelerates)
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| |-
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| ! [[Torsade de Pointes]]
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| | [[Image:tdp_small.svg|200px]]
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| | regular
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| | 150-300 bpm
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| | ventricle (VT)
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| | [[AV-dissociation]]
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| | no rate reduction (sometimes accelerates)
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| |-
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| ! [[Bundle-branch re-entrant tachycardia]]*
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| | [[Image:bb_reentry_small.svg|200px]] | |
| | regular
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| | 60-100 bpm
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| | 150-300 bpm
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| | ventricles (VT)
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| | [[AV-dissociation]]
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| | no rate reduction
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| |-
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| |colspan="8"|* Bundle-branch re-entrant tachycardia is extremely rare
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| |}
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| == Treatment == | | ==Treatment== |
| ===Defibrillation===
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| Indications for defibrillation include the following:
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| * [[Chest pain]]
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| * [[Congestive heart failure]] ([[CHF]])
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| * [[Hypotension]] with symptoms
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| * [[Loss of consciousness]]
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| * [[Seizure]]
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| === Acute Pharmacotherapies ===
| | [[Wide complex tachycardia medical therapy|Medical Therapy]] | [[Wide complex tachycardia primary prevention|Primary Prevention]] |
| * '''If stable''': (More patients than you think)
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| * '''DO NOT USE''' Ca2+ Channel blocker, [[Digoxin]] or [[Adenosine]] if you don't not know the etiology of the Wide Complex Tachycardia. Ca2+ Channel blockers and Digoxin can lead to accelerated conduction down a bypass tract and [[VF]].
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| * Though ACLS guidelines recommend a diagnostic trial of [[Adenosine]], it can precipitate [[VF]] in some patients with SVT. Patients who have underlying coronary disease may become ischemic from coronary steal. Rhythm can degenerate and lead to [[VF]] that cannot be resuscitated. Furthermore, some [[VT]] (esp those with structurally normal hearts) are [[adenosine]] responsive and can terminate.
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| *:# Etiology Uncertain
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| *:#:* [[Pronestyl]] 15mg/kg load over 30 minutes then 2-6mg/min gtt
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| *:# [[Ventricular Tachycardia]] with active ischemia
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| *:#:* [[Lidocaine]] 1 mg/kg q5-10 min up to 3 times then 2-6mg.min gtt
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| *:#:* If unsuccessful, [[Pronestyl]] as above
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| *:#:* If unsuccessful, IV [[Amiodarone]] 150-300 load over 15-20min. 30-60mg/hr gtt for total of 1gram
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| *:# [[Ventricular Tachycardia]] in Setting of [[Cardiomyopathy]]
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| *:#:* Skip [[Lidocaine]] and go straight to [[Pronestyl]]
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| *:# Positively [[SVT]] with aberrancy
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| *:#:* [[Adenosine]] 6mg rapid IV bolus in large vein. May repeat with 12mg x2.
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| *:#:* [[Lopressor]] 2.5-5.0mg IV
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| *:#:* [[Diltiazem]] 10-20mg bolus followed by gtt 5-20mg/hr
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| *:#:* [[Verapamil]] 2.5-5.0mg bolus.
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| *:#:* Avoid [[Digoxin]]. Takes too long to work and can be proarrhythmic
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| *:#:* [[Pronestyl]] as above
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| *:# Antidromic AVRT
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| *:#:* If 100% positive [[AF]] is not underlying, can terminate with a nodal blocker
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| *:#:* If unsure, [[Pronestyl]] as above
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| ==Sources== | | ==Case Studies== |
| Copyleft images obtained courtesy of ECGpedia, http://en.ecgpedia.org/index.php?title=Special:NewFiles&offset=&limit=500
| | [[Wide complex tachycardia case study one|Case #1]] |
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| == References ==
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| {{Reflist|2}}
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| [[Category:Electrophysiology]] | | [[Category:Electrophysiology]] |
| [[Category:Cardiology]] | | [[Category:Cardiology]] |
| | [[Category:Arrhythmia]] |
| [[Category:Emergency medicine]] | | [[Category:Emergency medicine]] |
| [[Category:Intensive care medicine]] | | [[Category:Intensive care medicine]] |
| | [[Category:Arrhythmia]] |
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| {{WikiDoc Help Menu}} | | {{WikiDoc Help Menu}} |
| {{WikiDoc Sources}} | | {{WikiDoc Sources}} |
