Anti-Arrhythmic Agents
Class Drug(s) Usual Dosing (adult) Indication Adverse Effects
I Moricizine 200-300mg q8h ventricular tachycardia dizziness, nausea, rash, seizures
Ia Disopyramide 150-200mg q6h or 300mg CR q12h atrial fibrillation, ventricular tachycardia anticholinergic effects, CHF
  Procainamide 250-500mg q3-6h or 500-100mg SR q6h (oral); 15-18mg/kg loading dose, then 1-4mg/min maintenance (IV) atrial fibrillation, ventricular tachycardia, Wolf-Parkinson-White arrhythmias GI effects, CNS effects, lupus-like syndrome, fever, hematological effects, anticholinergic effects
  Quinidine sulfate: 100-600mg q4-6h, gluconate: 324-972mg q8-12h (oral); 400mg q2-6h (IM); 200-400mg diluted & given <10mg/min (IV) paroxysmal supraventricular tachycardia, atrial fibrillation, ventricular tachycardia, Wolf-Parkinson-White arrhythmias hypotension, GI effects, thrombocytopenia, cinchonism
Ib Lidocaine IV only: initial 1-1.5mg/kg (may give 0.5-0.75mg/kg repeat dose if necessary), then 1-4mg/min maintenance ventricular tachycardia, ventricular fibrillation, PVC CNS and GI effects
  Mexiletine 200-300mg q8h ventricular tachycardia GI and CNS effects
  Tocainide 1200-1800mg/day in 3 divided doses ventricular tachycardia GI, CNS, and pulmonary effects, agranulocytosis
Ic Flecainide 50mg q12h for paroxysmial supraventricular arrhythmias; 100mg q12h for life-threatening arrhythmias; maximum dose 400mg/day ventricular tachycardia congestive heart failure, blurred vision, GI and CNS effects
  Propafenone immediate release: 100-300mg q8h; sustained release: 225-425 q12h ventricular tachycardia GI effects, blurred vision, dizziness
II Esmolol intraoperative tachycardia: 80mg bolus over 30 seconds, followed by 150mcg/kg/min infusion (up to 300mcg/kg/min); supraventricular tachycardia: 500mcg/kg bolus over 1 minute, then 50mcg/kg/min over 4 minutes, followed by infusion of 50-200mcg/kg/min ventricular tachycardia, supraventricular tachycardia congestive heart failure, lupus-like syndrome, hypotension, bradycardia, bronchospasm, CNS effects
  Propranolol 10-30mg q6-8h (oral); 1mg/dose slow IVP, may repeat every 5 minutes up to 5mg total (IV) supraventicular tachycardia, ventricular tachycardia, PVC, digoxin toxicity congestive heart failure, bradycardia, hypotension, fatigue, CNS effects
III Amiodarone oral: ventricular arrhythmias - 800-1600mg/day in 1-2 doses for 1-3 weeks, then decrease to 600-800mg/day in 1-2 doses when control achieved (maintenance 400mg/day); atrial fibrillation prophylaxis - 400mg bid for 7 days maximum; intravenous: breakthrough VF/VT - 150mg IV over 10 minutes; pulseless VF/VT - 300mg IV initial, then 150mg additional if no response, then 1mg/min for 6 hours followed by 0.5mg/min; A-fib prophylaxis - 1000mg IV over 24 hours for 2 days; stable VT/SVT - 150mg IV bolus over 10 minutes, then infusion of 1mg/min for 6 hours followed by 0.5mg/min over 18 hours ventricular tachycardia CNS, GI and thyroid effects, pulmonary fibrosis, liver toxicity, corneal deposits
  Bretylium immediate life-threatening ventricular arrhythmia: 5mg/kg initial over 1 minute (repeat 10mg/kg dose as necessary if arrhythmia persists, up to 30-35mg/kg); other life-threatening ventricular arrhythmias: 5-10mg/kg initial, may repeat every 1-2 hours; 5-10mg/kg every 6-8 hours maintenance ventricular tachycardia, ventricular fibrillation orthostatic hypotension, GI and CNS effects
  Dofetilide 125-500mcg twice daily (dosing based on renal function/QTc interval) atrial fibrillation headache, dizziness, ventricular tachycardia, torsade de pointes
  Ibutilide IV: < 60 kg: 0.01mg/kg over 10 minutes; > 60 kg: 1mg over 10 minutes (may repeat x 1 if arrhythmia persists) atrial fibrillation torsade de pointes, hypotension, branch bundle block, AV block, nausea, headache
  Sotalol ventricular arrhythmia: 80mg bid initial, 160-320mg/day usual dosing range; atrial fibrillation: 80mg bid initial; 80-160mg bid usual dosing range atrial fibrillation, ventricular tachycardia bradycardia, hypotension, congestive heart failure, fatigue, CNS effects
IV Diltiazem IV: 0.25mg/kg bolus over 2 minutes, followed by 5-15mg/hour maintenance infusion atrial fibrillation, paroxysmial supraventricular tachycardia hypotension, GI and liver effects
  Verapamil IV: 2.5-5mg over 2 minutes, may repeat in 15-30 minutes if inadequate response (maximum dose 20mg) atrial fibrillation, paroxysmial supraventricular tachycardia hypotension, congestive heart failure, bradycardia, vertigo, constipation
Miscellaneous Adenosine IV: 6mg, may repeat with 12mg dose in 1-2 minutes supraventicular tachycardia, paroxysmial supraventricular tachycardia flushing, dizziness, bradycardia, syncope
  Digoxin 0.125-0.5mg daily atrial fibrillation, paroxysmial supraventricular tachycardia arrhythmias, GI and CNS effects
  Magnesium life threatening arrhythmia: IV: 1-2g in 100ml D5W over 5-60 minutes, followed by infusion of 0.5-1g/hour OR 1-6g over several minutes, followed by 3-20mg/minute infusion for 5-48 hours ventricular tachycardia, ventricular fibrillation hypotension, hypothermia, myocardial depression, CNS effects
Atrial Fibrillation Atrial Flutter
1. Cardioversion (in unstable patients) - 200J initially, increasing to 300-360J as needed (sedate patient first if time permits) 1. Cardioversion (in unstable patients) - 50J and repeat as needed to maximum of 360J
2. Rate control - Verapamil 5mg IV over 2 minutes, followed by 5-10mg in 15-30 minutes if needed; Cardizem 0.25mg/kg IV over 2 minutes, then 0.35mg/kg over 2 minutes if needed; Lopressor 5mg iv every 5 minutes to total of 15mg 2. Rate control (normal LV function) - Cardizem 0.25mg/kg iv over 2 minutes, then 0.35mg/kg iv over 2 minutes if needed; Verapamil 2.5-5mg iv over 2 minutes, then 5-10mg in 15-30 minutes if needed
3. Impaired LV function - Amiodarone 150mg iv over 10 minutes, then 1mg/min infusion x 6 hours followed by 0.5mg/min x 18 hours; Cardizem 0.25mg/kg over 2 minutes, then 0.35mg/kg over 2 minutes if needed 3. Rate control (impaired LV function) - Digoxin 0.5mg iv, then 0.25mg iv every 6 hours (maximum 1mg load); if needed Cardizem 0.25mg/kg iv over 2 minutes, then 0.35mg/kg iv over 2 minutes if needed
4. Anticoagulants: Heparin 80u/kg iv bolus, then 18u/kg/hr and adjust based on aPTT (drawn every 6 hours until stable); start coumadin after 24 hours (10mg/day x 2 days, then titrate to INR)
Ventricular Fibrillation Ventricular Tachycardia
1. Defibrillation - attempt immediately: adults 200J, 200-300J, then 360J; pediatrics 2J/kg, 2-4J/kg, then 4J/kg 1. Pulseless VT - treat as a VF with defibrilation and CPR
2. Unstable VT - synchronized cardioversion: use 100J, 200J, then up to 360J (peds: 0.5-1J/kg, up to 2J/kg) as needed (sedate first if time permits)
2. Airway management - 100% O2, intubate, and mechanical ventilation
3. Vasopressors - Epinephrine (1:10000) 1mg iv every 3-5 minutes (ped 0.01mg/kg iv/io, or 0.1mg/kg et, if unsuccessful, consider high dose: 0.1-0.2mg/kg iv/io/et every 3-5 minutes); vasopressin 40u iv once 3. Stable monomorphic VT (normal LV function) - consider procainamide or sotalol
4. Stable monomorphic VT (impaired LV function) - consider amiodarone or lidocaine then cardioversion
4. Antiarrhythmics - Amiodarone 300mg iv, then 150mg iv if needed (peds: 5mg/kg iv/io); follow each medication dose with countershock 360J (peds 4J/kg) 5. Stable polymorphic VT (normal QT interval) - treat ischemia and correct electrolytes; normal LV function - consider beta-blockers, amiodarone, lidocaine; impaired LV function - consider amiodarone or lidocaine then cardioversion
6. Stable polymorphic VT (prolonged QT interval) - stop causative medications, correct electrolytes, consider magnesium, and cardiac pacing
 
Paroxysmal Supraventricular Tachycardia Sinus Tachycardia
1. Unstable patients - cardioversion: 50J initially, then increase to 100J, 200J, 300J, 360J (sedate with diazepam 5-10mg iv); peds: 0.5J/kg, increase to 1J/kg, 2J/kg) 1. IV fluids (dehydration or blood loss) - 250ml NS iv boluses (1-2L iv for major trauma)
2. Beta blockers (myocardial ischemia, sympathomimetic withdrawal, or thyroid storm) - Lopressor 5mg iv every 5 minutes up to 15mg; Propranolol 0.5-1mg iv over 5 minutes, then 1mg increments every 2 minutes (maximum 5mg)
2. Stable patients - adenosine 6mg rapid iv followed by rapid saline flush, then 12mg if no response after 1-2 minutes (peds 0.1mg/kg iv, then 0.2mg/kg); Verapamil 2.5-5mg iv over 2 minutes, then 5-10mg in 15-30 minutes as needed
3. Calcium channel blockers (critically ill patients with contraindication to beta-blockers) - Cardizem 10mg iv slowly, then continuous infusion of 5-10mg/hr (may increase up to 30mg/hr)
4. Benzodiazepines (alcohol withdrawal, cocaine) - Ativan 1-2mg iv, may repeat every 5 minutes as needed
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