Features: always associated with absent pulse and loss of consciousness
ECG
- chaotic disorganised broad complex rhythm with rate of 300-600 bpm
- initially high amplitude (coarse)
- amplitude becomes less with time and eventually becomes asystole after 1 – 3 minutes
- approx. 3% of asystole is really VF (either unipolar or fine)
Differential diagnosis
- shivering artefact: native rhythm still usually visible
- severe tremor: usually regular and low amplitude
- loose lead connection: high amplitude spiking pattern
Management: Electrical cardioversion
- non synchronised
- energy setting
- monophasic
- adults 360 J
- children: 4 J/kg (although little evidence that 4J/kg is more effective than 2J/kg)
- biphasic
- 150 J to 200 J for a biphasic truncated exponential waveform
- 120 J for a rectilinear biphasic waveform
- repeated shocks should be given following drug therapy
- monophasic
Management: Drug therapy
- only after failed electrical cardioversion and CPR
- adrenaline
- dose of 1 mg IV after 2nd DCR then after every second 2 minute CPR cycle
- amiodarone
- may improve outcome
Special circumstances
- active core rewarming if T < 30o C
- HCO3 if Na channel blocker toxicity present
- K+ replacement if significant hypokalaemia present
