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| {{Infobox_Disease | | | __NOTOC__ |
| Name = {{PAGENAME}} |
| | {| class="infobox" style="float:right;" |
| Image = |Lead II rhythm ventricular tachycardia Vtach VT.JPG |
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| Caption = |
| | | [[File:Siren.gif|30px|link=Wide complex tachycardia resident survival guide]]|| <br> || <br> |
| DiseasesDB = 13819 |
| | | [[Wide complex tachycardia resident survival guide|'''Resident'''<br>'''Survival'''<br>'''Guide''']] |
| ICD10 = {{ICD10|I|47|2|i|30}} |
| | |} |
| ICD9 = {{ICD9|427.1}} |
| | {| class="infobox" style="float:right;" |
| ICDO = |
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| OMIM = |
| | | [[File:Physician_Extender_Algorithms.gif|88px|link=Wide complex tachycardia physician extender algorithm]]|| <br> || <br> |
| MedlinePlus = |
| | |} |
| eMedicineSubj = emerg |
| | {{Wide complex tachycardia}} |
| eMedicineTopic = 634 |
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| eMedicine_mult = {{eMedicine2|med|2367}} {{eMedicine2|ped|2546}} |
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| MeshID = D017180 |
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| }}
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| {{SI}} | |
| {{WikiDoc Cardiology Network Infobox}}
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| {{CMG}} | | {{CMG}} |
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| {{Editor Help}}
| | '''For patient information, click [[Wide complex tachycardia (patient information)|here]]''' |
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| == Overview ==
| | {{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 |
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| '''Wide complex tachycardia''' or WCT refers to a cardiac rhythm of more than 100 bpm with a QRS duration of 120 ms or more on the surface electrocardiogram.
| | ==[[Wide complex tachycardia overview|Overview]]== |
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| === Definition === | | ==[[Wide complex tachycardia causes|Causes]]== |
| Heart rate >100 with QRS duration >120ms.
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| === Background ===
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| * Wide complex tachycardia (WCT) can be either:
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| *:# Supra ventricular tachycardia (SVT) with aberrancy
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| *:# Ventricular tachycardia (VT)
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| *:# Antegrade conduction down an accessory bypass tract.
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| * 80% of WCT will be VT. 98% will be VT if structural heart disease is present. 7% of patients with SVT will have prior myocardial infarction (MI).
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| == Differential Diagnosis == | | ==[[Wide complex tachycardia differential diagnosis|Differentiating VT from SVT as a Cause of Wide Complex Tachycardia]]== |
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| * '''Regular'''
| | ==[[Wide complex tachycardia epidemiology and demographics|Epidemiology and Demographics]]== |
| *:* VT (slight irregularity of RR)
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| *:* SVT with aberrancy: Sinus, atrial tachycardia (AT), or Flutter.
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| *:* Antidromic atrioventricular reentrant tachycardia (AVRT)
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| * '''Irregular'''
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| *:* First 50 beats of VT
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| *:* SVT with aberrancy: [[Atrial fibrillation]], multifocal atrial tachycardia (MAT)
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| *:* [[Atrial fibrillation]] with bypass tract
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| * 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.
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| * 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.
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| * In use-dependent aberration, a patient on and anti-arrhythmic (especially 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.
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| === Differentiation of VT from Antidromic AVRT ===
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| * Angina pectoris (AP) activate ventricles from base to apex by virtue of their location in the atrioventricular (AV) ring. This results in predominately positive QRS complexes in V4-V6. If negative, favors VT. For same reason, qR complexes in V2-V4 cannot be found in AVRT unless there is preexisting heart disease.<ref>Brugada P, Brugada J, Mont L et al. A new approach to the differential diagnosis of a regular tachycardia with wide QRS complex. Circulation. 1991;83: 1649-1659. PMID 2022022</ref> <ref>Kindwall KE, Brown, J, Josephson ME. Electrocardiographic criteria for ventricular tachycardia in wide complex left bundle branch block morphology tachycardias. Am J Cardiology. 1988; 61:1279-1283. PMID 3376886</ref> <ref>Podrid P, Brugada P. Approach to wide QRS complex tachycardias. Up To Date. 1998.</ref>
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| * Because the atria are part of the circuit in AVRT, any relationship other than 1:1 of P and QRS means VT (100%).
| | ==[[Wide complex tachycardia risk factors|Risk Factors]]== |
| ==== Algorithm ==== | |
| # If polarity of V4-V6 is negative, then VT (100%).
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| # If qR present in V4-V6, then VT (100%).
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| # If 1:1 AV relationship not present (more QRS than P), then VT. (100%)
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| * '''If none of above present, 25% will still be VT'''
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| == History and Symptoms == | | ==[[Wide complex tachycardia natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| * Age
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| * Presence of preexisting heart disease
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| * Duration of symptoms
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| * Medications
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| == Physical Examination == | | ==Diagnosis== |
| * Vitals to assess hemodynamic stability
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| * ''“Cannon-a waves”'' (a manifestation of AV dissociation)
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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==
| | [[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]] |
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| * Extreme axis deviation favors VT. Especially -90 to -180 or “northwest” or “superior” axis. (23% of SVT will have SAD)
| | ==Treatment== |
| * 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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| == Pharmacotherapy ==
| | [[Wide complex tachycardia medical therapy|Medical Therapy]] | [[Wide complex tachycardia primary prevention|Primary Prevention]] |
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| === Acute Pharmacotherapies === | | ==Case Studies== |
| * '''If stable''': (More patients than you think)
| | [[Wide complex tachycardia case study one|Case #1]] |
| * '''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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| * Pearls from MEJ
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| *:* In [[right bundle branch block]] ([[RBBB]]) morphology with normal or inferior axis, R/S ratio may be >1 in VT or <1 in [[SVT]]
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| *:* If [[QRS]] during tachycardia is narrower than in normal [[sinus rhythm]] (NSR), suggests [[VT]]
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| == Surgery and Device Based Therapy ==
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| * Hypotension with symptoms, chest pain, congestive heart failure (CHF), seizure etc.: Defibrillate
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| == References ==
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| {{Reflist}}
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| {{Electrocardiography}}
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| {{SIB}}
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| [[Category:Electrophysiology]] | | [[Category:Electrophysiology]] |
| [[Category:Cardiology]] | | [[Category:Cardiology]] |
| | [[Category:Arrhythmia]] |
| | [[Category:Emergency medicine]] |
| | [[Category:Intensive care medicine]] |
| | [[Category:Arrhythmia]] |
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