Surgical Critical Care: Antiarrhythmic Pharmacology

Antiarrhythmic Pharmacology

Adenosine

  • Use: SVT
  • MOA: Blocks Adenosine Receptors of AV Nodal Cells
  • Contraindications:
    • Asthma or Bronchospasm
    • Second/Third Degree Heart Block
  • Dose: 6 mg IV
    • If Fails After 2 Minutes: 12 mg IV
    • If Fails After 2 Minutes Again: 12 mg IV
  • *Decrease Dose by 50% if Given Through a Central Line

Amiodarone

  • Use: Atrial Fibrillation/Flutter, VT or VF
  • MOA: Potassium-Blocker
  • Dose:
    • Atrial Fibrillation/Flutter & Ventricular Tachycardia:
      • Bolus: 150 mg & Repeat if Needed
      • Continuous: 1 mg/min for 6 Hours, then 0.5 mg/min
    • Ventricular Fibrillation:
      • First Dose: 300 mg Bolus
      • Second Dose: 150 mg
  • Less Cardiac Depression than Diltiazem – Favored Agent in Concomitant Heart Failure
  • Can Convert to Sinus Rhythm & May Risk Clot Embolization

Atropine

  • Use: Sinus Bradycardia or AV Blocks
  • Dose: 0.5 mg Every 3-5 Minutes (Maximum 3 mg Total)

Digoxin

  • Use: Atrial Fibrillation/Flutter
  • MOA: AV Node Inhibition & Ionotropic Stimulation by Na-K ATPase Pump Inhibition
  • Dose:
    • First: 0.25 mg Every 2-4 Hours for a Maximum Total Dose of 1.0-1.5 mg
    • Then: 0.125-0.375 mg Daily
  • Used Only as an Adjunctive Therapy
  • Slow-Acting & Should Not Be Used as the Sole Therapy

Diltiazem

  • Use: Atrial Fibrillation/Flutter
  • MOA: Calcium Channel Blocker
  • Dose:
    • Bolus: 0.25 mg/kg
      • Give Second Bolus of 0.35 mg/kg After 15 Minutes if Needed
    • Continuous: 5-15 mg/hr
  • Superior to Amiodarone After the First Hour of Therapy
  • Negative Inotropic Effects but Used Safely in Moderate-Severe Heart Failure

Epinephrine

  • Use: Ventricular Fibrillation, PEA or Asystole
  • Dose: 1 mg Every 3-5 Minutes

Esmolol

  • Use: Atrial Fibrillation/Flutter
  • MOA: β-Blocker
  • Ultra-Short-Acting Allows Rapid Dose Titration
  • Dose:
    • Bolus: 500 mcg/kg
    • Continuous: 50-300 mcg/kg/min

Metoprolol

  • Use: Atrial Fibrillation/Flutter or MAT
  • MOA: β-Blocker
  • Dose: 5 mg Every 5-10 Minutes as Needed (Total of 3 Doses)

Verapamil

  • Use: MAT
  • MOA: Calcium Channel Blocker
  • Dose: 0.25-5.0 mg Every 15-30 Minutes (Total Dose of 20 mg)
  • Contraindicated in Heart Failure