• HR 200+ should make you think of a pre-excitation syndrome
• Don't try to be clever with drugs in WPW

• congenital accessory atrioventricular conduction pathway
  • circuit is OUTSIDE AV node = AVRT
• retrograde conduction can cause SVT
  • AF and Aflutter can also occur

• arrhythmias
  • perioperative SVT / AF

• ECG
  • 1: Short PR interval < 120 ms
  • 2: Wider QRS > 100 ms
  • 3: Delta wave = slurred upstroke / short upslope on R wave
    • short upslope to R wave
  • ECG pattern depends on where the accessory pathway inserts

• ie. known WPW and not in tachycardia / arrhythmia
• procedural
  • EPS with RF catheter ablation
  • 1st line
    • symptomatic WPW syndrome
    • patients with high-risk occupations
  • has replaced surgical treatment and most drug treatments
• pharmacological
  • patients who refuse RF ablation

• orthodromic
  • anterograde through AVN + retrograde through AP
  • this is a narrow complex tachycardia
  • treatment is the SAME as AVNRT ***
• antidromic
  • this is a WIDE complex tachycardia
  • if unstable, must cardiovert
  • if stable
    • 1st line = procainamide = 17 mg/kg = 1.2 g
      • Class Ia
    • amiodarone 150 mg over 10 mins
      • Class III
  • be very careful with drugs in antidromic AVRT
    • see below

• Pre-op
  • continue usual anti-arrhythmics
  • prepare for ARR+ HDI = emergency trolley, defib, drugs
• Intra-op
  • avoid ⬆ENS = pain, anxiety, light anaesthesia
  • avoid drugs causing ⬆HR = atropine, ketamine
  • avoid drugs causing AVN block = ABCD = adenosine, BB, CCB, digoxin
  • okay to use = AP blockers
• Post-op

AVRT + Drugs

• AVN Blockers
  • avoid in WPW (ie. not in SVT)
    • may precipitate antidromic AVRT SVT
  • MUST NOT give in (established) antidromic AVRT SVT (WIDE complex)
  • anterograde conduction through AP (accessory pathway)
    • because AVN is blocked
    • there may be retrograde conduction through AP as well
    • this is 1:1 conduction and is VT/VF = unstable and potentially lethal
  • ABCD = adenosine, beta-blockers, CCB, digoxin
• AP Blockers (block accessory pathway)
  • these are safer
  • Class I = procainamide, flecainide
  • Class III = amiodarone, sotalol

https://www.anesthesiaconsiderations.com/wolff-parkinson-white-wpw

https://www.healio.com/cardiology/learn-the-heart/ecg-review/ecg-topic-reviews-and-criteria/wpw-review

https://litfl.com/whos-afraid-of-the-big-bad-wolff/

https://emedicine.medscape.com/article/159222-treatment

https://litfl.com/pre-excitation-syndromes-ecg-library/