What is the management of Supraventricular Tachycardia (SVT) with aberrancy versus Ventricular Tachycardia (VT)?

From the Guidelines

The management of supraventricular tachycardia (SVT) with aberrancy versus ventricular tachycardia (VT) begins with accurate differentiation between these two conditions, as treatment approaches differ significantly. When uncertain about the diagnosis, it is safest to treat as VT, especially in patients with structural heart disease or prior myocardial infarction. For hemodynamically unstable patients with either condition, immediate synchronized cardioversion at 100-200 joules is indicated 1. For stable SVT with aberrancy, vagal maneuvers should be attempted first, followed by adenosine (6 mg IV rapid push, followed by 12 mg if needed, up to two doses) 1. If adenosine fails, consider calcium channel blockers like diltiazem (0.25 mg/kg IV over 2 minutes) or beta-blockers such as metoprolol (5 mg IV over 2-5 minutes, up to 3 doses) 1. Some key points to consider in the management of SVT include:

• EP study with the option of ablation is useful for the diagnosis and potential treatment of SVT 1
• Oral beta blockers, diltiazem, or verapamil is useful for ongoing management in patients with symptomatic SVT 1
• Flecainide or propafenone is reasonable for ongoing management in patients without structural heart disease or ischemic heart disease who have symptomatic SVT 1 For stable VT, amiodarone (150 mg IV over 10 minutes, followed by 1 mg/min infusion for 6 hours) is the first-line medication, with lidocaine (1-1.5 mg/kg IV bolus, followed by 0.5-0.75 mg/kg every 5-10 minutes if needed) as an alternative, particularly in ischemic settings 1. Procainamide (20-50 mg/min until arrhythmia suppression, hypotension, QRS widening >50%, or maximum 17 mg/kg) can be considered in the absence of structural heart disease. The distinction between these conditions is crucial because administering calcium channel blockers or beta-blockers to patients with VT can cause hemodynamic collapse, while treating SVT with aberrancy using VT protocols may expose patients to unnecessary antiarrhythmic medications with potential side effects. Some important considerations in the management of VT include:
• Immediate electrical cardioversion of VT is recommended for sustained, unstable, and stable VT 1
• For acute conversion of VT that is sustained, haemodynamically stable, and monomorphic, i.v. sotalol or procainamide should be considered 1
• For long-term management of idiopathic sustained VT oral metoprolol, propranolol or verapamil is recommended 1

From the FDA Drug Label

Amiodarone hydrochloride injection is indicated for initiation of treatment and prophylaxis of frequently recurring ventricular fibrillation (VF) and hemodynamically unstable ventricular tachycardia (VT) in patients refractory to other therapy.

The management of Supraventricular Tachycardia (SVT) with aberrancy versus Ventricular Tachycardia (VT) is not directly addressed in the provided drug labels.

• The labels discuss the use of amiodarone for VT and VF, but do not provide information on how to differentiate or manage SVT with aberrancy versus VT.
• No conclusion can be drawn regarding the management of SVT with aberrancy versus VT based on the provided information 2, 2.

From the Research

Management of Supraventricular Tachycardia (SVT) with Aberrancy versus Ventricular Tachycardia (VT)

• The management of wide complex tachycardias, including SVT with aberrancy and VT, depends on the diagnosis and the patient's hemodynamic stability 3, 4.
• The differential diagnosis of wide complex tachycardia includes SVT with aberrancy or underlying bundle branch block and antegrade SVT conduction over an accessory pathway (antidromic SVT) 3.
• Clinical criteria, such as the presence of structural heart disease or a history of previous myocardial infarction, and electrocardiographic criteria, such as the presence of capture or fusion beats, can be useful in diagnosing wide complex tachycardia 3, 4.
• The acute management of wide complex tachycardia includes cardioversion and intravenous pharmacologic therapy, with unstable patients requiring immediate cardioversion 4.
• Chronic treatment of patients prone to VT may include complex pharmacotherapy and automatic implantable cardioverter-defibrillators (AICDs) 4.

Diagnostic Challenges

• Differentiation between VT and SVT with aberrancy based on the 12-lead ECG alone can be imprecise, and an electrophysiology study (EPS) may be necessary to confirm the diagnosis 5.
• Conventional ECG criteria may have reduced sensitivity to distinguish VT from SVT with aberrancy in patients with idiopathic VT, particularly in those with septal sites of origin 6.
• Careful examination of all available rhythm data and consideration of an EPS can confirm SVT and obviate the need for ICD therapy 5.

Treatment Options

• Adenosine is appropriate when wide QRS SVT is the diagnosis, and it also has been used as a diagnostic aid to identify dysrhythmias 4.
• Magnesium sulfate may be useful in refractory cases of VT and torsades de pointes 4.
• Ablation therapy may be effective in treating SVT with aberrancy, with a high success rate and low recurrence rate 5.