Wide Complex Tachycardia

See Also

Epidemiology

Wide Complex Tachycardia in Children
1. Presumptive Ventricular Tachycardia
Wide Complex Tachycardia in Adults
1. 75% of patients have Ventricular Tachycardia
2. 90% of patients with CAD have VT
References
1. Akhtar (1988) Ann Intern Med 109:905-912 [PubMed]

Differential Diagnosis
Regular Wide Complex Tachycardia

Monomorphic Ventricular Tachycardia
1. Precautions
  1. Safest to start treating as Ventricular Tachycardia (see Ventricular Tachycardia Management for precautions)
    1. No algorithm (e.g. Basel or Brugada as below) completely excludes Ventricular Tachycardia
2. Criteria
  1. Wide QRS Complex (duration at least 0.12 sec) for >=3 consecutive beats AND
  2. No P Wave to QRS Complex relationship (other than retrograde P Waves)
  3. Tachycardia (Heart Rate >130, and typically >150 bpm, may be as slow as 120 in some cases)
    1. VT rates may be <130 bpm with antidysrhythmics (e.g. Amiodarone, Sotalol, Flecainide)
    2. Slower rates 120-30 may also be due to Hyperkalemia, Sodium Channel Blocker Toxicity, AIVR
3. Types
  1. Nonsustained: <30 seconds and no hemodynamic instability
  2. Sustained: >=30 seconds (or hemodynamic instability)
4. Other findings suggestive of Ventricular Tachycardia
  1. QRS Complex duration >200 msec (almost always VT)
  2. Atrioventricular Dissociation (ventricular rate > atrial rate)
  3. Fusion Beats
    1. Supraventricular and ventricular waves fuse to form an irregular QRS
    2. Occur sporadically on the EKG
  4. Brugada Sign
    1. Time from start of QRS Complex to S wave lowest point (nadir) is >100 msec
  5. Josephson Sign
    1. Notching of the S wave downslope before its lowest point (nadir)
  6. QRS Complex concordance across the precordium
    1. Most or all leads V1-V6 have predominately positive or negative QRS Complexes
  7. Absence of a typical RBBB or LBBB
  8. Extreme axis deviation with QRS Axis between -90 and 180 degrees (northwest axis)
  9. Right bundle branch morphology of the QRS (RSR' or "rabbit ears")
    1. R Wave taller than the R' wave (Left rabbit ear taller than the right)
5. References
  1. Berberian (2024) Crit Dec Emerg Med 38(2): 14-5
  2. Mattu (2022) Crit Dec Emerg Med 36(5): 11
Accelerated Idioventricular Rhythm (AIVR)
1. Heart Rates typically 40 to 120 bpm
2. Benign transient Dysrhythmia (typically lasts minutes and resolves)
3. Occurs after coronary reperfusion (spontaneous or after PCI, Fibrinolysis)
4. Differentiate from Ventricular Tachycardia which presents with Heart Rates >120-130
5. Observation of suspected AIVR rhythm only
  1. Antidysrhythmic medications may degenerate AIVR to Asystole
Antidromic Atrioventricular Reciprocating Tachycardia (AVRT)
1. Paroxysmal Supraventricular Tachycardia (30% of cases) with an accessory pathway (outside the AV Node)
Aberrant Conduction
1. Causes
  1. Left or Right Bundle Branch Block
  2. Metabolic abnormalities
  3. Hyperkalemia
  4. Ventricular paced rhythm
  5. Ventricular Preexcitation (e.g. WPW)
  6. Sodium Channel Blocker Toxicity (Acute Poisoning)
    1. AVR with dominant R Wave or R/S Wave >0.7
    2. P Waves may be subtle (but are often present)
    3. Critical to identify as repeated doses of Sodium Bicarbonate (until QRS narrows) is life saving
2. Rhythms
  1. Sinus Tachycardia with Aberrant Conduction
  2. Supraventricular Tachycardia with Aberrant Conduction
    1. Prior EKG demonstrating Left Bundle Branch Block
    2. QRS wide, regular and consistent across EKG leads

Evaluation
Basel Algorithm for Wide Complex Tachycardia

Criteria
1. Clinical high risk features
  1. Myocardial Infarction
  2. Congestive Heart Failure with Reduced Ejection Fraction <35%
  3. Automated Implantable Defibrillator
2. EKG findings
  1. Lead II Time to first peak >40 ms
  2. Lead aVR Time to first peak >40 ms
Interpretation
1. Ventricular Tachycardia is suggested by >1 of the above criteria
2. SVT with aberrancy may be present if <=1 of the above criteria
References
1. Moccetti (2022) JACC Clin Electrophysiol 8(7): 831-9 +PMID: 35863808 [PubMed]

Evaluation
Brugada criteria for Wide Complex Tachycardia

Only treat as SVT with aberrancy if ALL 4 criteria are absent
1. Rule has a Test Sensitivity and Test Specificity >96% for VT
Criteria (presence of any one of which suggests Ventricular Tachycardia)
1. RS complex absent from all precordial leads
2. R to S interval >100 ms in one precordial lead
3. Atrioventricular Dissociation
4. Morphologic criteria for Ventricular Tachycardia in leads V1, V2, V6
References
1. Brugada (1991) Circulation 83(5): 1649-59 [PubMed]

Management
Acute Wide Complex Tachycardia

Electrical cardioversion is the safest and most effective strategy in wide complex tachydysrhthmia
1. In contrast, with antiarrhthmics, many wide Tachycardias (e.g. Prolonged QTc, Brugada) degenerate into Cardiac Arrest
New emphasis on use of choosing only one Antiarrhythmic
1. Contrast to prior Antiarrhythmic soups
2. Pro-arrhythmic effects increase with Polypharmacy
3. Procainamide is most effective of the Antiarrhythmics for stable Monomorphic Ventricular Tachycardia
  1. Stable Monomorphic Ventricular Tachycardia (avoid in Prolonged QTc, Brugada Syndrome)
See Ventricular Tachycardia Management in the Adult
See Ventricular Tachycardia Management in the Child

Management
Chronic recurrent Ventricular Tachycardia

Implantable Defibrillator (ICD)
1. Long term best option (much better than meds)
2. Efficacy: 40-50% reduction in sudden death
3. References
  1. (1997) N Engl J Med 337:1576 [PubMed]
  2. Moss (1996) N Engl J Med 335:1933-40 [PubMed]
Maximize Coronary Artery Disease management
1. Bigger (1997) N Engl J Med 337:1569-75 [PubMed]