APPROACH TO WIDE QRS COMPLEX APPROACH TO WIDE QRS COMPLEX TACHYCARDIATACHYCARDIA

Dr HA TUAN KHANHDr HA TUAN KHANH

Dr DAVID TRANDr DAVID TRAN

ContentContent

1. Definition

2. Causes of WCT

3. Diagnosis criteria Clinical history Physical examination ECG criteria: Brugada criteria, other criteria, findings favoring

SVT, VT vs AVRT criteria

4. Management Unstable hemodynamic Stable hemodynamic

DefinitionDefinition

Wide QRS complex tachycardia is a rhythm with a rate of more than

100 b/m and QRS duration of more than 120 ms

VT (80%)

SVT (20%)

Stewart RB. Ann Intern Med 1986

• Supraventricular tachycardia

- with prexsisting BBB

- with BBB due to heart rate (aberrant conduction)

- antidromic tachycardia in WPW syndrome

• Ventricular tachycardia

Causes of wide QRS complex tachycardia

SVT vs VT Clinical history

Medication Drug-induced tachycardia → Torsade de pointes

Diuretics

Digoxin-induced arrhythmia → [digoxin] ≥2ng/l or normal if hypokalemia

Age - ≥ 35 ys → VT (positive predictive value of 85%)

Underlying heart disease Previous MI → 98% VT

Pacemakers or ICD Increased risk of ventricular tachyarrhythmia

SVT vs VTSVT vs VTPhysical examination Physical examination

Physical findings that indicate presence of AV dissociation (cannon

A waves, variable-intensity S1,variation in BP unrelated to

respiration) if present are useful

Termination of WCT in response to maneuvers like Valsalva, carotid

sinus pressure, or adenosine is strongly in-favor of SVT but there

are well-documented cases of VT responsive to these

SVT vs VTECG criteria: Brugada algorithm

Brugada P. Ciculation 1991

Step 1

Step 2

Step 3

Step 4: LBBB - type wide QRS complex

SVT VT

small R wave notching of S waveR wave >40ms

fast downslopeof S wave

no Q wave

Q wave

> 70ms

V1

V6

Step 4: RBBB - type wide QRS complex

SVT VT

V1

V6

or

or

R/S > 1 R/S ratio < 1 QS complex

rSR’ configuration monophasic R wave qR (or Rs) complex

Step 4: RBBB morphology

Step 4: LBBB morphology

Other ECG criteriaOther ECG criteria

• North - west QRS axis deviation

• Negative or positive concordance

• Fusion beats, capture beats

• Ventriculoatrial conduction with block

• RBBB morphology with LAD > - 300

• LBBB morphology with RAD > + 900

• Previous ECG show MI or previous ECG show that during sinus rhythm, bifascular block is present, which changes in configuration during tachycardia

Concordance and Northwest Axis

Fusion beat and capture beat

Ventriculoatrial conduction with block

RBBB morphology with LAD

LBBB morphology with RAD

Previous MI

Previous LBBB

Findings favoring SVTFindings favoring SVT

• Triphasic pattern in V1 and V6• Rabbit’s ear• Previous ECG: Preexistent BBB or preexcitation

Triphasic patternTriphasic pattern

Rabbit’s earRabbit’s ear

Wide complex SVT from preexisting RBBBWide complex SVT from preexisting RBBB

Wide complex SVT from preexisting LBBBWide complex SVT from preexisting LBBB

VT vs AVRTVT vs AVRTECG criteriaECG criteria

Brugada P. Ciculation 1991

Wide complex SVT from bypass tractWide complex SVT from bypass tract

Summary : diagnosis evaluationSummary : diagnosis evaluation

ACC/AHA/ESC guidelines for management of pt with SVT. Circulation 2003

Management – Hemodynamic compromiseManagement – Hemodynamic compromise

1. Unstable patient, but still responsible with a discernible BP and/or pulse:

- Emergent synchronized cardioversion

- If the QRS complex and T wave cannot be distinguished accurately → immediate defibrillation

2. Unstable patient, unresponsive or pulseless → standard ACLS resusciation algorithms

ACLS pulseless arrest algorithmACLS pulseless arrest algorithm

AHA Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Ciurculation 2005

Management – Stable hemodynamicManagement – Stable hemodynamic

1. VT or WCT of uncertain etiology: Any associated conditions (cardiac ischemia, heart failure,

electrolyte abnormalities or drug toxicities) Class I and III antiarrhythmic drugs

- Amiodarone: 150mg IV/10mins followed by an infusion of 1mg/min for 6 hours, then 0,5mg/min

- Procainamide: 15-18mg/kg infusion over 25-30mins, followed by 1-4mg/min by continuous infusion

- Lidocaine: 1-1,5mg/kg IV/2-3mins followed by an infusion of 1-4mg/min

Urgent or elective cardioversion

Management – Stable hemodynamicManagement – Stable hemodynamic

2. SVT Vagal maneuvers: carotid sinus pressure (if no carotid bruits)

or Valsava maneuver Adenosine: 6mg over 1-2 seconds. If the initial dose is

ineffective, a 12mg dose may be given and repeated once if necessary

Calcium channel blocker (Verapamil 2.5 to 5mg IV) or beta blokers (Metoprolol 5 to 10 mg IV)

Cardioversion

Acute management hemodynamically stable and regular tachycardiaAcute management hemodynamically stable and regular tachycardia

ACC/AHA/ESC guidelines for management of pt with SVT. Circulation 2003

Recommendation acute management hemodynamically stable Recommendation acute management hemodynamically stable and regular tachycardiaand regular tachycardia

ACC/AHA/ESC guidelines for management of pt with SVT. Circulation 2003

Tachycardia algorithmTachycardia algorithm

AHA Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Ciurculation 2005

Tachycardia algorithmTachycardia algorithm

Thank you for your attentionThank you for your attention