We do the sorting. You do the medicine.
Cardiac · Core11 / 22

WPW with pre-excited AF after intubation24-year-old man, 78 kg, for elective arthroscopic ACL reconstruction

Rhythm problem: pre-excited AF and the unstable tachycardia algorithm

From memory: the diagnosis and the notes are hidden. Answer each question aloud, then press Show.

Know this first

  • WPW ECG in adults: PR under 120 ms, delta wave, QRS over 120 ms.
  • AF down the accessory pathway can produce very fast rates and VF.
  • AV-nodal blockers in pre-excited AF are dangerous.
  • Unstable: synchronised cardioversion. Stable: procainamide, max 50 mg/min.

The patient

24-year-old man, 78 kg, for elective arthroscopic ACL reconstruction. Palpitations twice a year; ECG shows PR 100 ms, delta waves and a wide QRS. Never seen by electrophysiology. No regular drugs; otherwise fit, plays football weekly. Vitals: BP 124/72, HR 68, SpO2 99%, RR 12.

The examiner asks

Answer aloud, then press Show.

  1. Consider

    What are your concerns?

    Show the answerHide the answer
    • A fit 24-year-old with pre-excitation and palpitations, for elective knee ligament surgery. Patient
    • His short PR and delta waves mean a pathway bypassing the AV node. Disease
    • If he develops AF, that pathway can conduct very fast and degenerate into VF.

  2. Prepare

    Would you proceed today?

    Show the answerHide the answer
    • Urgency: elective knee surgery, so there is time to treat his pathway first. Stem trigger
    • Active cardiac conditions? None now, he's in sinus; but his pathway could produce one. Disease
    • Risk score: no RCRI items, so RCRI 0.
    • Functional capacity: football weekly, well over 4 METs.
    • Decision: electrophysiology study and ablation first, then his knee.
    • If he must proceed, defibrillator pads on before induction given his palpitations.
    • Procainamide in the room; no plan to use AV-nodal blockers. Crisis

  3. Plan

    How do you conduct the anaesthetic?

    Show the answerHide the answer
    • No sympathetic surges: calm induction and adequate depth before stimulation. Disease
    • Blunt laryngoscopy with remifentanil 1 mcg/kg or lidocaine 1–1.5 mg/kg. Airway
    • No ketamine; it pushes his heart rate up. Disease
    • Good analgesia after, then electrophysiology referral. After surgery

  4. Crisis

    After intubation the ECG shows an irregular broad-complex rhythm at 240/min; BP 82/50. What do you do?

    Show the answerHide the answer
    • Tachycardia algorithm: irregular broad-complex at 240, BP 82/50; pre-excited AF, unstable. Crisis
    • Call for help; synchronised cardioversion now, starting at 200 J or more.
    • If he were stable, procainamide at up to 50 mg/min.
    • His pathway branch: no adenosine, verapamil, diltiazem, beta-blocker, digoxin or IV amiodarone.
    • If he degenerates into VF: defibrillate at once and start CPR.
    • Monitored after surgery, with ablation arranged. After surgery

Fatal mistakes

  • An AV-nodal blocker for pre-excited AF.
  • An unsynchronised shock while he still has a pulse.
  • Proceeding with elective surgery without electrophysiology review.

Checked against: Stoelting 8e · Miller 10e · AHA guidelines: adult advanced life support (2025)

Report a problem with this case

Mark Got it only if you said every point. Again brings the case back tomorrow; Got it brings it back in 3, then 7, 14 and 30 days.

All Cardiac casesBack to today