Who’s Afraid Of The Big Bad Wolff?

A 61 year old male walks up to the triage desk complaining of a funny feeling in his chest. He has had similar milder episodes in the past and has been investigated by his GP with no firm diagnosis being reached.

He’s moved to Resus as he’s a bit pale and sweaty.

His ECG is shown below:

WPW atrial fibrillation rapid ventricular response

Initially you wonder if it might be Ventricular tachycardia (VT) as it seems broad and fast and initially seems regular, however after watching the monitor for a bit and stroking your Mo, you become convinced the rhythm is actually irregular.

You decide he’s on the ‘unstable’ side of the spectrum and perform DC Cardioversion.  Post Cardioversion, his ECG looks like this:

WPW delta waves

He’s admitted under the care of Cardiology who perform an ablation. Post ablation his ECG looks like this:

WPW Post Ablation

Wolff – Parkinson – White Syndrome:

  • ECG pattern depends on where the accessory pathway inserts.
  • Classically:
    • Short PR interval <120 msecs.
    • QRS > 100msecs.
    • Delta wave = slurred upstroke at beginning of QRS.
  • Different insertions:
    • Normal QRS if pathway inserts into infranodal conduction tissue just below AV node
    • Grossly wide and abnormal QRS if pathway inserts into non-conduction tissue.

Key Management Points:

  • A heart rate ≥ 200 should make you think of a pre-excitation syndrome.
  • Narrow complex SVT is treated identically to non-WPW SVT.
  • Don’t try and be clever with drugs in broad complex tachycardias and WPW.
  • Using AV nodal blockers in WPW and AF can result in 1:1 conduction to the ventricles.
  • This is also know as Ventricular Fibrillation.
  • Just shut-up + DC cardiovert them.

References

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Comments

    • VinceD says

      I’m assuming she was in a typical AVNRT, which responds to standard SVT therapy, as opposed to AVRT or atrial fib with WPW (as above).

  1. Hillis says

    Nice presentation .. Does it mean that evey narrow complex tachycardia should be considered as accessory pathway syndrome until proven otherwise !! OR in other way how we can definitively said it’s WPW not SVT esp.the treament of both is different . Shall we give to such rythm adenosine firslty for differentiation !!!

  2. MM says

    By giving AV-nodal blocking medications (Cardizem/Diltiazem for example) is that it can cause a paradoxical effect of increasing the heart rate to a lethal level and also hypotension which may precipitate cardiac arrest. Cardizem is a strong vasodilator and sometimes may lead to a significant drop in BP. If their pre-drug BP is hairy, give a fluid bolus of 200-500 mL of NSS (absence CHF of course). If they develop hypotension following the medication then treat w/ fluids first (always listen to lung sounds).

    In my agency for a known or suspected (through EKG) WPW we go directly to Amiodarone (150mg in 250 ML NSS wide open over 10 min).

    If you have a symptomatic or hemodynamically unstable patient (keep in mind that everyone is symptomatic at different rates -- 130 BPM may be too much for an elderly patient but someone in their 30′s might not become symptomatic until their rate reaches 250). Symptomatic is when they started complaining of chest pain/pressure, shortness of breath, and are pale, cool, diaphoretic, etc. When the aren’t able to maintain their blood pressure is when they are known as hemodynamically unstable. If you’re allowed, give Versed (or Valium, or Ativan, etc) and then cardiovert them. Typically 50-100 j is the starting. In my agency we are starting with 120j for the first and 220j for the second. And prior to cardioversion remember that if they are in AF and have been complaining of these symptoms for 48+ hours you have to be cautious with the micro-emboli formation in the atria that may break off and lodge in their brain and lead to a stroke.

    Hope that was helpful.

  3. Nathan says

    A pt has ventricular escape with a prolonged inverted PRI of greater than .12 sec. This Pt also has a hx of WPW. Can WPW cause a prolonged inverted P-wave since the PRI in an escape rhythm is usually less than .12 sec?

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