Peri-Arrest Rhythms: Tachycardia

Key points

• Resuscitation Council UK (2021): a single adult tachycardia algorithm covers all tachyarrhythmias; assess with ABCDE and treat reversible causes.
• Life-threatening adverse features — shock, syncope, myocardial ischaemia, heart failure — indicate the patient is unstable.
• Any adverse feature → synchronised DC cardioversion, up to 3 attempts (sedation/anaesthesia if conscious). If it fails and the patient remains unstable, give amiodarone 300 mg IV over 10–20 min (then 900 mg over 24 h) and re-attempt cardioversion.
• Broad-complex regular → treat as VT: amiodarone 300 mg IV over 20–60 min, then 900 mg over 24 h (if previously confirmed SVT with bundle branch block, treat as narrow-complex). Broad-complex irregular → AF with BBB (treat as narrow-complex), or polymorphic VT/torsades → magnesium sulfate 2 g (8 mmol) IV over 10 min.
• Narrow-complex regular → vagal manoeuvres, then adenosine 6 mg → 12 mg → 18 mg rapid IV boluses (if no pre-excitation); if unsuccessful, verapamil or a beta-blocker and consider atrial flutter (rate control). Narrow-complex irregular → probable AF: rate control (beta-blocker, or diltiazem) and anticoagulate; consider cardioversion if onset <48 h.

Decision points in this pathway

• Any adverse signs present?
• Broad-complex tachycardia?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.