Wide complex tachycardia overview
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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.
Causes
A wide complex tachycardia is either of ventricular origin (ventricular tachycardia or VT), or is of supraventricular origin with aberrant conduction (SVT with aberrancy) such as occurs with conduction down a bypass tract.
Differential Diagnosis of Wide Complex Tachycardia: Distinguishing VT from SVT
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:
- There is a history of myocardial infarction 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).
Supraventricular Tachycardia with Aberrant Conduction
The diagnosis of atrial fibrillation with aberrant conduction down a bypass tract should be considered if the heart rate is over 200 beats per minute or if the rhythm is grossly irregular.
For more detailed information regarding how to differentiate VT from SVT please view the differential diagnosis page or click here.
Epidemiology and Demographics
The underlying cause of wide complex tachycardia tends to be ventricular tachycardia (VT) in older patients and supraventricular tachycardia (SVT) with aberrancy in younger patients.
Risk Factors
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.
Electrocardiogram
Laboratory Studies
Electroyte abnormalities such as hypokalemia (which can be associated with ventricular tachycardia), hypomagnesemia (which can lead to Torsade de Pointes) and hyperkalemia (which can cause a sinusoidal rhythm) 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.
| 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 ACLS guidelines for the management of tachycardia.