What is the role of lidocaine (anti-arrhythmic medication) in the management of supraventricular tachycardia (SVT)?

Lidocaine Has No Role in SVT Management

Lidocaine is explicitly ineffective for supraventricular tachycardia (SVT) and should not be used. 1 The drug is specifically indicated for ventricular arrhythmias, not supraventricular rhythms.

Why Lidocaine Does Not Work for SVT

• Lignocaine (lidocaine) has no effect on supraventricular tachycardia (SVT), as clearly stated in guidelines for arrhythmia management 1
• Lidocaine is a class IB antiarrhythmic that works by blocking sodium channels in ventricular tissue, but lacks efficacy on the AV node or atrial tissue where SVT circuits typically reside 1
• The mechanism of action makes it fundamentally unsuitable for treating reentrant circuits involving the AV node (AVNRT) or accessory pathways (AVRT), which account for most SVT cases 2

Correct Acute Management of SVT

For hemodynamically stable SVT:

• Vagal maneuvers first (Valsalva maneuver preferred, with 27.7% success rate when combined with carotid massage) 2, 3
• Adenosine 6 mg rapid IV bolus if vagal maneuvers fail, followed by 12 mg if no response within 1-2 minutes (91-95% success rate) 2, 3
• IV diltiazem (0.25 mg/kg over 2 minutes) or verapamil (5-10 mg IV over 2 minutes) as second-line alternatives if adenosine fails (64-98% success rate) 2, 4
• IV beta blockers (metoprolol 2.5-5 mg IV over 2 minutes) can be used but have more limited evidence 3

For hemodynamically unstable SVT:

• Immediate synchronized cardioversion without delay for pharmacologic trials 2, 3

Critical Pitfall to Avoid

Never use AV nodal blocking agents (verapamil, diltiazem, beta blockers, digoxin) in patients with pre-excited atrial fibrillation or Wolff-Parkinson-White syndrome, as they may enhance accessory pathway conduction and precipitate ventricular fibrillation 2, 4

When Lidocaine IS Appropriate

Lidocaine is reserved exclusively for ventricular tachycardia, particularly when associated with acute myocardial ischemia or infarction:

• Stable monomorphic VT: 50 mg IV over 2 minutes, repeated every 5 minutes to total dose of 200 mg, then 2-4 mg/min infusion 1
• Polymorphic VT with acute MI: May be reasonable specifically in this context 1
• However, even for VT, lidocaine has limited efficacy (only 8-35% termination rate in studies) and procainamide is generally preferred 5, 6

The bottom line: If you're treating SVT and considering lidocaine, stop—you're treating the wrong rhythm or using the wrong drug. 1