FRCA Notes

Tachycardia

This page is concerned with new-onset tachycardia intra-operatively.

There are separate pages on perioperative management of patients with known arrhythmia, arrhythmia in pregnancy and arrhythmia following cardiac surgery.

Resources

  • Tachycardia is typically defined as a HR >100bpm
  • It may be further sub-classified according to:
    • Whether or not it is associated with haemodynamic instability or other life-threatening features
    • The width of the QRS complexes; narrow (<120ms) or broad (>120ms)
    • The regularity of said complexes; regular or irregular

Patient factors

  • Pre-existing arrhythmia e.g. known AF, WPW
  • Pre-existing cardiac disease e.g. IHD
  • Electrolyte disturbance inc. potassium, calcium, magnesium
  • Pain/stimulation

Anaesthetic & drug factors

  • The AAGBI say tachycardia in theatre is often due to one of:
    • Inadequate depth of anaesthesia or analgesia
    • As part of the baroreceptor reflex in response to hypotension

  • Other causes in this category include:

Surgical factors


  • Management of intra-operative tachycardia follows the Resus Council and AAGBI guidelines linked above
  • In short:
    • If no pulse → start CPR
    • If worsening hypotension, impending arrest or other life-threatening features → synchronised DC cardioversion
    • If otherwise benign tachycardia without hypotension → time to fiddle with drugs first, initially increasing the depth of anaesthesia/analgesia

DCCV energies

  • The Resus Council suggest an initial energy of:
    • 70 - 120J for SVT and atrial flutter
    • 120 - 150J for AF and broad-complex tachycardia
    • Increased in a stepwise fashion e.g. to 200J, then 360J

  • The AAGBI QRH by comparison suggests a starting energy of 50-100J biphasic for an adult
  • This appears to short-change those in AF or broad-complex tachycardia when compared to the Resus Council guidance

  • In reality one should:
    • Follow local trust guidelines (if they exist or differ from the above)
    • Seek senior help
    • Use the lowest possible energy to successfully cardiovert your patient

Drugs

  • The Resus Council and AAGBI are largely agreeable on drugs, e.g.:
    • Broad-complex, regular, tachycardia e.g. pulsed VT → amiodarone 300mg over 10mins
    • Polymorphic VT → magnesium 2g over 10mins
    • SVT → adenosine 6mg | 12mg | 18mg (or could consider propofol!)
    • AF → β-blocker or amiodarone ± digoxin
      • The AAGBI is more explicit with regards to β-blocker, suggesting either emsolol or labetalol (both 0.5mg/kg e.g. 25-50mg)