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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Wolff-Parkinson-White syndrome and pre-excitation

Cardiology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Escalate

An irregular broad-complex tachycardia in a patient with pre-excitation may be pre-excited AF and can deteriorate to ventricular fibrillation. If unstable, perform immediate synchronised cardioversion; if pulseless, follow the shockable cardiac-arrest algorithm.

Synopsis

Recognise ventricular pre-excitation, manage AV re-entry and pre-excited atrial fibrillation safely, and identify who needs electrophysiology risk assessment or ablation.

  • Pre-excitation means an accessory atrioventricular pathway conducts to the ventricle outside the AV node; WPW syndrome is pre-excitation plus symptomatic tachyarrhythmia.
  • The sinus-rhythm ECG classically shows a short PR interval, slurred initial QRS upstroke (delta wave) and a widened QRS.
  • Orthodromic AV re-entrant tachycardia is usually regular and narrow because antegrade conduction uses the AV node; antidromic AVRT is broad.
  • Pre-excited AF is irregular and broad with beat-to-beat QRS variation and potentially extreme ventricular rates.
  • Do not give adenosine, beta-blockers, diltiazem, verapamil, digoxin or amiodarone to pre-excited AF; AV nodal block can favour conduction down the accessory pathway.
  • For stable pre-excited AF, current RCUK options are procainamide or cardioversion; instability requires cardioversion.
  • Catheter ablation is first-line definitive treatment for symptomatic recurrent AVRT and for pathways with high-risk conduction properties.

Key red flags

Pre-excited AF

An irregular broad tachycardia with changing QRS morphology and very short RR intervals is the critical pattern.

Clinical red flags

Syncope during tachycardia, documented AF, very rapid episodes, resuscitated arrest, multiple pathways or a high-risk occupation/sport accelerate specialist assessment.

Investigation priorities

01
12-lead ECG in sinus rhythmFirst step

Confirm and localise pre-excitation and look for alternative conduction disease.

Management branches

regular-narrowStable regular narrow tachycardia

The rhythm is regular, QRS is under 120 ms and there is no evidence of pre-excited AF.

  1. Record a 12-lead ECG and perform vagal manoeuvres while monitoring continuously.
  2. If unsuccessful and there is no pre-excitation in the tachycardia, give adenosine 6 mg as a very rapid IV bolus followed by a flush.
  3. If needed give 12 mg, then 18 mg as very rapid IV boluses while recording a multi-lead ECG; this is the March 2026 RCUK sequence.
  4. If adenosine fails or instability develops, obtain expert help and use synchronised cardioversion; never transfer this sequence to an irregular broad rhythm.

Key medicines

AdenosineRCUK March 2026: 6 mg by very rapid IV bolus, then 12 mg if unsuccessful, then 18 mg if still unsuccessful, each followed by a rapid flush and given with continuous ECG recording. This resuscitation-algorithm sequence differs from the cited product SmPC's licensed 3 mg, 6 mg, then 12 mg sequence.Do not use in irregular broad-complex tachycardia or pre-excited AF. The cited UK SmPC contraindicates bronchospastic chronic lung disease including asthma, long-QT syndrome, severe hypotension, decompensated heart failure, and sick-sinus or second-/third-degree AV block without a functioning pacemaker. Avoid with dipyridamole; if essential, stop dipyridamole 24 hours beforehand or use a greatly reduced adenosine dose under expert direction. Sensitivity after heart transplantation may be increased.
ProcainamideRCUK: 10-15 mg/kg IV over 20 minutes, maximum 1 g, with continuous ECG and blood-pressure monitoring.Stop or slow for hypotension or marked QRS/QT prolongation; avoid combining with another QT-prolonging antiarrhythmic and seek expert help.
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Sources and review status6 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • Resuscitation Council UK: Adult tachyarrhythmia algorithm, March 2026Adenosine sequence, pre-excited AF and broad-complex routes.
  • Resuscitation Council UK: Adult advanced life support 2025Instability criteria and cardioversion principles.
  • ESC: 2019 supraventricular tachycardia guidelineAccessory-pathway assessment and treatment.
  • ESC: Ablation of accessory pathwaysHigh-risk EP thresholds and ablation indications.
  • NHS: Wolff-Parkinson-White syndromeSymptoms, emergency advice and definitive ablation overview.
  • eMC: Adenosine 3 mg/mL injection SmPCProduct-specific licensed dosing, contraindications and dipyridamole interaction, contrasted with the current RCUK algorithm.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom