When to cardiovert (cardioversion) a patient with wide complex tachycardia?

When to Cardiovert Wide Complex Tachycardia

Immediate synchronized cardioversion should be performed for hemodynamically unstable patients with wide complex tachycardia. 1, 2

Assessment of Hemodynamic Stability

• Signs of hemodynamic instability include hypotension, acutely altered mental status, signs of shock, chest pain, or acute heart failure symptoms 1, 2
• If any of these signs are present, the patient requires immediate intervention without delay 2

Treatment Algorithm

For Hemodynamically Unstable Patients

• Perform immediate synchronized cardioversion (with prior sedation in the conscious patient) 1, 2
• Cardioversion is highly effective in terminating wide-complex tachycardia and avoids complications associated with antiarrhythmic drug therapy 1, 2
• If initial cardioversion is unsuccessful, repeat cardioversion with higher energy levels 2
• After cardioversion, monitor for atrial or ventricular premature complexes that may trigger recurrence 2

For Hemodynamically Stable Patients with Monomorphic VT

• Procainamide is recommended for patients who do not have severe congestive heart failure or acute myocardial infarction 1
• Amiodarone is recommended for patients with or without severe congestive heart failure or acute myocardial infarction 1, 3
• Sotalol may be considered for patients with hemodynamically stable sustained monomorphic VT, including patients with acute myocardial infarction 1
• If pharmacological therapy is ineffective or contraindicated, synchronized cardioversion is recommended 1

For Regular Stable Wide-Complex Tachycardia of Uncertain Etiology

• IV adenosine may be considered relatively safe for both treatment and diagnosis if the rate is regular and the QRS is monomorphic 1
• Adenosine should NOT be given for unstable or irregular or polymorphic wide-complex tachycardias, as it may cause degeneration to ventricular fibrillation 1
• Verapamil is contraindicated for wide-complex tachycardias unless known to be of supraventricular origin 1

For Polymorphic Wide-Complex Tachycardia

• If associated with familial long QT syndrome: IV magnesium, pacing, and beta-blockers are recommended; avoid isoproterenol 1
• If associated with acquired long QT syndrome: IV magnesium is recommended; consider pacing or isoproterenol if accompanied by bradycardia 1
• If without long QT syndrome: Consider IV beta-blockers (for ischemic VT or catecholaminergic VT) or isoproterenol 1

For Pre-excited AF (Wide Complex)

• For hemodynamically unstable patients: Immediate synchronized cardioversion 1
• For hemodynamically stable patients: Ibutilide or IV procainamide 1, 4
• Avoid AV nodal blocking agents (beta blockers, diltiazem, verapamil, digoxin) as they may enhance conduction over the accessory pathway 1

Common Pitfalls and Caveats

• Do not delay cardioversion in hemodynamically unstable patients to attempt pharmacological conversion 2, 5
• Avoid calcium channel blockers such as verapamil and diltiazem in patients with ventricular tachycardia, as they can worsen hemodynamic status 2
• Proper synchronization of the cardioversion is crucial to avoid delivering the shock during the vulnerable period of the cardiac cycle 2
• Resuscitation equipment should be readily available as cardioversion may occasionally induce ventricular fibrillation or asystole 2
• A precordial thump may be considered for patients with witnessed, monitored, unstable ventricular tachycardia if a defibrillator is not immediately ready for use 1
• When uncertain about the origin of a wide complex tachycardia, it is safer to treat it as ventricular tachycardia 6, 5