Synopsis
Recognise ventricular ectopy, VT, torsades and VF, then choose the correct shock, drug and investigation branch without delaying resuscitation.
- A ventricular ectopic is a premature broad QRS without a normal preceding P wave; frequent/complex ectopy is a clue, not by itself an indication for suppression.
- NSVT is at least three ventricular beats ending spontaneously within 30 seconds; sustained VT lasts at least 30 seconds or requires earlier termination because of instability.
- Monomorphic VT has a stable QRS morphology; polymorphic VT varies beat to beat; torsades is polymorphic VT in the setting of QT prolongation.
Key red flags
Regular broad-complex tachycardia with a consistent QRS shape, usually from a fixed re-entry circuit in scar or cardiomyopathy. AV dissociation, capture/fusion beats and concordance support VT, but absence does not exclude it.
Investigation priorities
Separate arrest from peri-arrest VT and capture diagnostic morphology without delaying shock.
Management branches
Unresponsive, abnormal breathing and shockable rhythm with no pulse/signs of circulation.
- Start high-quality CPR, call the arrest team and defibrillate as soon as possible. Use one shock followed immediately by two minutes of CPR.
- Manual biphasic first shock: at least 150 J (130-150 J for pulsed biphasic); escalate subsequent shocks when possible. If device recommendations are unknown, use the highest adult energy setting.
Sustained regular broad monomorphic VT with a pulse and no life-threatening feature.
Key medicines
Adrenaline in shockable cardiac arrest1 mg IV/IO after the third total shock, then 1 mg every 3-5 minutes while ALS continues.
Amiodarone in VF/pulseless VT300 mg IV/IO after the third total shock; a further 150 mg after the fifth total shock.