Lignocaine Use in Ventricular Tachycardia

Introduction to Lignocaine Administration

• The American College of Cardiology recommends lignocaine as a second-line agent for stable VT, with amiodarone and beta-blockers preferred as first-line therapy, particularly in patients with structural heart disease 1
• For hemodynamically stable ventricular tachycardia, lignocaine is administered as an initial bolus of 50 mg IV over 2 minutes, repeated every 5 minutes to a total dose of 200 mg, followed by a maintenance infusion of 2 mg/min 2

Hemodynamic Assessment and Initial Treatment

• Before administering lignocaine, assess whether the patient is hemodynamically stable or unstable by checking for systolic blood pressure ≤90 mmHg, chest pain suggesting ongoing ischemia, acute heart failure with pulmonary edema, altered mental status indicating inadequate cerebral perfusion, and signs of shock 1
• If any of these adverse signs are present, immediate synchronized DC cardioversion (100J, 200J, 360J) takes priority over drug therapy 3, 2, 1

Lignocaine Dosing Regimens

• The European Society of Cardiology recommends amiodarone (150 mg IV over 10 minutes, then 1.0 mg/min infusion) combined with IV beta-blockers as the preferred initial treatment for hemodynamically stable VT 1
• For stable VT with pulse, the initial dose of lignocaine is 50 mg IV over 2 minutes, repeated every 5 minutes to a total dose of 200 mg, followed by a maintenance infusion of 2 mg/min 2
• Alternative dosing (ACC/AHA Protocol) includes a loading bolus of 1.0-1.5 mg/kg IV (maximum 100 mg), with additional boluses of 0.5-0.75 mg/kg every 8-10 minutes if needed, and a maximum total loading of 3-4 mg/kg 4, 5, 2

Special Considerations

• Lignocaine remains the drug of choice specifically in the acute MI setting when VT occurs 4, 5
• Reduce the maintenance infusion rate in elderly patients (≥70 years), heart failure or cardiogenic shock, and after 24-48 hours 5, 4, 2
• Monitor continuously for early signs of central nervous system toxicity, including nausea, drowsiness, perioral numbness, dizziness, confusion, slurred speech, muscle twitching, seizures, and respiratory depression 2

Contraindications and Cautions

• Do not use lignocaine as first-line therapy in polymorphic VT storm, torsades de pointes, severe shock, or heart block 6, 1, 3, 4
• Lignocaine depresses myocardial contractility, requiring careful monitoring especially in hemodynamically compromised patients 2

Alternative Therapies

• If VT persists or recurs despite lignocaine, amiodarone is indicated for VT refractory to lignocaine: 5 mg/kg (300 mg) over 15 minutes for life-threatening situations, or over one hour for stable patients 2
• Procainamide is an alternative: 20-30 mg/min up to 10-17 mg/kg loading dose 2, 1
• Bretylium is used for refractory VT: 5 mg/kg diluted with 100 mL dextrose, with possible further dose of 10 mg/kg 4, 2

Lidocaine Dosing and Clinical Use in Refractory Ventricular Arrhythmias

Dosage Recommendations (American Heart Association 2018)

• The initial lidocaine dose for cardiac arrest due to refractory ventricular fibrillation/ventricular tachycardia is 1.0–1.5 mg/kg IV/IO (weight‑based, not a fixed 100 mg). Subsequent doses of 0.5–0.75 mg/kg IV/IO may be given every 5–10 minutes, with a maximum cumulative dose of 3 mg/kg; a maintenance infusion of 1–4 mg/min (≈20–50 µg/kg/min) follows. 7

• For pulseless ventricular fibrillation/ventricular tachycardia, the AHA 2018 protocol specifies:

Indications Relative to Amiodarone (American Heart Association 2018)

• Lidocaine may be used when amiodarone is unavailable (e.g., drug shortage or lack of stock). [7][8]

• Lidocaine is appropriate in witnessed cardiac arrests because the shorter interval to drug delivery can improve early outcomes. 7

• Both lidocaine and amiodarone improve survival to hospital admission in witnessed arrests, although neither has demonstrated a benefit in long‑term survival or neurological outcome. 7

• Amiodarone remains first‑line (300 mg IV/IO followed by 150 mg) when it is available, in patients with structural heart disease or heart failure, and for refractory VF/VT after defibrillation. [7][8]

• Lidocaine is recommended as an alternative when amiodarone is unavailable, in the setting of acute myocardial infarction, or when a witnessed arrest permits rapid drug administration. [7][8]7

Contraindications (American Heart Association 2018)

• Do not use lidocaine for torsades de pointes; magnesium sulfate (2 g IV) should be administered instead. [8][9]

Evidence Summary (American Heart Association 2018)

• The AHA 2018 guidelines acknowledge that both lidocaine and amiodarone increase the likelihood of ROSC and survival to hospital admission in witnessed cardiac arrests, supporting the use of lidocaine when amiodarone cannot be given. 7