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Lesson

Pre-Excited AF (WPW)

12 min Cardiac & ECG Skip to quiz

Objective: Treat an irregular wide-complex tachycardia as possible pre-excited atrial fibrillation (WPW, Wolff-Parkinson-White). Do not block the atrioventricular node. If the patient is unstable, use synchronized cardioversion.

Why this matters

Check for a pulse first. This rhythm looks like atrial fibrillation with a rapid ventricular response (AF with RVR), so crews reach for diltiazem or adenosine. Do not. Wolff-Parkinson-White (WPW) is an extra pathway from the atria to the ventricles. If that pathway is conducting, a drug that blocks the atrioventricular (AV) node sends more impulses down the pathway. That can cause ventricular fibrillation (VF). If the patient is unstable, use synchronized cardioversion.

Key points
  • If they are unstable — hypotension, shock, ischemic pain, altered mental status, or acute heart failure — use synchronized cardioversion per protocol. That is the same path as other unstable tachycardias.
  • Do not give adenosine, diltiazem, verapamil, a beta-blocker, or digoxin for irregular wide-complex tachycardia.
  • Procainamide, or another protocol drug that acts on the pathway, is for stable patients and only if your protocol includes it. If you do not carry it, you still do not give diltiazem.

Clinical sequence

  1. Check for a pulse. If there is none, this is arrest. Start CPR and defibrillate polymorphic VT or VF if that is the rhythm.
  2. If there is a pulse, protect the airway, breathing, and circulation. Get a 12-lead if it will not delay care of an unstable patient.
  3. If the strip is irregular and wide, treat it as pre-excited AF until proven otherwise.
  4. If they are unstable, use synchronized cardioversion. If they are stable, use the drug your protocol names. Do not give an atrioventricular-node blocker just to see what happens.
  5. After conversion, get a 12-lead. Delta waves may appear. Tell the emergency department which drugs you did not give.

Teaching points

  • The pattern is irregularly irregular, with a wide or changing QRS, and often a very fast rate, sometimes over 200.
  • The trap is treating it like AF with RVR or like regular supraventricular tachycardia (SVT). Adenosine and calcium-channel blockers such as diltiazem or verapamil are the wrong drugs here.
  • If the patient is unstable, use electricity. Set synchronized cardioversion to the energy in your protocol. It is the same kind of treatment as other unstable tachycardias.
  • A regular narrow SVT is a different lesson. This lesson is the irregular wide rhythm.
Verbalize
  • This rhythm is irregular and wide. I am not giving adenosine or diltiazem.
  • The patient is unstable. I am preparing synchronized cardioversion.
  • If they arrest, treat it as VF or pulseless VT.
  • Tell the emergency department this may be pre-excited AF, and that no atrioventricular-node blocker was given.

Common errors

  • Giving adenosine just to see what happens on an irregular wide tachycardia.
  • Giving diltiazem because the monitor said AF.
  • Waiting for a perfect 12-lead while the systolic blood pressure is 70.

Practice

One-minute check

The monitor shows an irregular wide rhythm at 220, BP 78/40, and the patient is sweating. Name the drug you will not give and the next action. Then the same tracing is present, BP is 128, and the patient is talking. What drug still stays off the list?

Related: Wide-Complex Tachycardia, Synchronized Cardioversion.

Sources & Further Study

Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.

Education only. Apply learning within your protocols and medical direction. This is not clinical care guidance.

Check Your Understanding

Questions drawn only from this lesson. After you check, the key is highlighted. Education practice — not a certification exam.

1. An irregular wide-complex tachycardia should be treated as:
2. Adenosine, diltiazem, beta-blockers, and digoxin in pre-excited AF:
3. Unstable irregular wide-complex tachycardia with a pulse should get:
4. If you do not carry procainamide and the patient is still stable:
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