1. SBP < 90
2. HR < 40
3. ventricular arrhythmias + hypotension
4. heart failure

1. recent asystole
2. AV block 2nd degree Type 2 = Mobitz = constant interval
3. AV block 3rd degree = complete HB
4. Ventricular pause > 3 secs

• reactive
• non-reactive = persistent despite stimulation / arousal / wakefulness

• sleep, athletes

• B = Resp = hypoxia (eg. children)
• C = Cardiac = MI, sick sinus syndrome
• D = Neuro = high spinal, ⬆ICP
• D = Mechanical vagal stimuli
  • Valsalva manoeuvre
  • visceral organ stretch / tension / distension / retraction = peritoneum, anus, cervix, bladder, ocular muscles
  • airway stimulation
  • extraocular muscle retraction
• D = Drugs
  • opioids, neostigmine, BB
• E = Endocrine
  • hypothermia
  • hypothyroidism
• F = Renal
  • Hyperkalaemia

• usually 40-45 bpm
• rates below = ⬇CO

Stop all vagal stimuli

If ADVERSE SIGNS, muscarinic antagonist

• atropine 0.5 mg IV

If persistent adverse signs / risk of asystole

• interim measures = drugs + external pacing
• transvenous pacing

12-lead ECG

• determine if sinus / junctional / other rhythm

INTERIM MEASURES

• muscarinic antagonist
  • atropine 20 mcg/kg IV (min 100 mcg, max 3 mg)
• beta-1 agonist
  • isoprenaline
  • adrenaline 2-10 mcg/min IV
• transcutaneous (external) pacing
  • use minimal current to achieve this
    • usually 50-100 mA to achieve capture
  • paeds = HR 100
• alternate drugs
  • aminophylline
  • dopamine
  • glucagon
  • glycopyrrolate

NB. delay in onset of treatment ⬅ ⬇CO

severe bradycardia = CPR may be required to move drugs to heart