Direct Current Cardioversion

Airway: Own, consider RSI if requires airway protection
Access: Small IV
Pain: Requires sedation. Myalgias may be present post-operatively.
Position: Semi-erect
Time: Minutes
Blood loss: Nil
Special: Requirement for anticoagulation; risk of burns

Restoring sinus rhythm through use of a brief electrical discharge across the heart. May be:

Considerations

  • A
    • Airway protection
      May be required if emergent/unfasted.
  • C
    • Digoxin toxicity
      Contraindication
    • Duration of arrhythmia
      AF for ⩾48 hours requires TOE exclusion of thrombus.
    • Optimised for successful cardioversion
      • Nil digoxin toxicity
      • Normal electrolytes
    • Underlying CVS disease
      May pre-dispose to CVS dysfunction with anaesthesia.
  • E
    • Fire risk
      • Remove facemask oxygen/cease NP oxygen
      • Remove GTN patches
  • H
    • Anticoagulation

Preparation

  • Standard ANZCA monitoring
  • Preoxygenation
  • Pads away from ICD (if present)

Induction

Deep sedation adequate, analgesia rarely required

  • Gentle IV induction
    Consider:
    • 1-1.5mg/kg propofol given slowly
    • Alfentanil
    • Remifentanil

Emergency drugs:

  • Atropine
  • Isoprenaline
    Available but not drawn up.

Intraoperative

Complications include:

  • VF
  • Catecholamine surge
    May precipitate MI.
  • Asystole
  • Rhabdomyolysis/muscle injury
    Rare.

Optimising Cardioversion

Modifiable factors:

  • Equipment
    • Larger electrode size
      ↓ impedance.
    • Skin contact
      Consider salt gels.
    • Pad position
      AP or AL.
    • Repeated shock
      Impedance ↓ with subsequent shocks.
    • Biphasic defibrillation
  • Patient
    • Respiration
      End-expiration reduces thoracic wall impedance.
    • Electrolytes
    • TFTs
    • Medications

Relatively non-modifiable factors:

  • Body habitus
    ↑ BMI ↑ impedance.
  • Duration of AF
  • Structural heart disease

Postoperative

  • ECG to verify NSR

References