Wolff-Parkinson-White Syndrome: A Friendly Guide for Junior Doctors in ED

Welcome to another installment of "Emergency Medicine Made Easy." Today, we’ll crack open the mystery of Wolff-Parkinson-White (WPW) Syndrome — a condition that looks scary on an ECG but becomes manageable with the right clinical reasoning and timely decisions.

Let’s go step by step: from history-taking to examination, then investigations, and finally, management.

What is WPW, in Simple Words?

Wolff-Parkinson-White (WPW) is a pre-excitation syndromewhere an accessory electrical pathway (the Bundle of Kent)bypasses the AV node, allowing impulses to travel directly from the atria to the ventricles.

This creates a risk of reentrant tachyarrhythmias, including AVRT (atrioventricular reentrant tachycardia) and, dangerously, pre-excited atrial fibrillation — which can degenerate into VF.

HISTORY-TAKING: What Questions Should You Ask?

Start with the symptom story — most cases present with palpitations.

Here’s your WPW-specific question checklist:

🔹 Presenting Complaint:

• “Can you describe what you felt?” (palpitations, dizziness, chest pain, SOB, syncope)

• “Did you pass out? Did anyone witness it?” (look for syncope vs seizure)

• “How long did it last?”

• “What were you doing when it started?”

🔹 Pattern and Triggers:

• “Does it start and stop suddenly?” (suggests paroxysmal SVT)

• “Any known triggers? Caffeine, alcohol, exertion?”

🔹 Associated Symptoms:

• “Did you feel lightheaded or faint?”

• “Any chest pain or shortness of breath?”

🔹 Past Medical History:

• “Have you ever had similar episodes before?”

• “Any known heart conditions?”

• “Ever been told you have an abnormal ECG or arrhythmia?”

🔹 Family History:

• “Anyone in the family with sudden cardiac death or arrhythmias?”

🔹 Drug History:

• “Do you take any regular medications?” (especially AV nodal blockers)

• “Any recreational drugs or supplements?”

EXAMINATION: What to Look For?

Often, the patient may be asymptomatic at rest, especially between episodes. But here’s what you need to check:

During an Episode:

• Vitals: Check for tachycardia, hypotension, or hypoxia

• Heart sounds: May be normal or irregular if in AF

• Signs of shock: Cool peripheries, altered mental status

• Neck: Look for ‘cannon A waves’ (if AV dissociation)

• Chest: Rule out heart failure signs (crackles, raised JVP)

Post-Episode:

• May return to normal sinus rhythm — don’t be falsely reassured

• Look for underlying structural heart disease signs (e.g. murmurs)

INVESTIGATIONS: What Should You Order?

ECG — The Most Crucial Tool:

When the patient is in sinus rhythm, look for the classic WPW triad:

1. Short PR interval (<120ms)

2. Delta wave (slurred upstroke of QRS)

3. Widened QRS complex (>120ms)

!

If in Tachyarrhythmia:

• Could be orthodromic AVRT (narrow complex) or pre-excited AF (irregular, wide complex, very fast).

• NEVER mistake pre-excited AF for polymorphic VT!

Other Tests:

• Bloods: FBC, U&E, TFTs (look for electrolyte imbalances, thyrotoxicosis)

• Cardiac enzymes: If chest pain or concerns of ischemia

• CXR: If suspecting structural disease

• Echocardiogram: To rule out structural abnormalities

• Referral for Electrophysiology (EP) Study

MANAGEMENT PLAN: What Should You Do?

If Stable Tachyarrhythmia:

If it’s SVT (narrow complex, regular):

• Try vagal maneuvers first.

• If fails: Give adenosine IV ONLY IF you are confident it’s not pre-excited AF.

Caution:In pre-excited AF, never give AV nodal blockers (e.g. adenosine, beta-blockers, calcium channel blockers, digoxin) → may cause VF!

If Pre-excited AF (Irregular, Wide Complex, Fast):

This is a true medical emergency.

✅ If stable:

• Procainamide IV or flecainide (if no structural heart disease)

• Monitor on telemetry

• Involve cardiology early

If unstable (hypotension, chest pain, altered mental status):

• Immediate DC cardioversion

Long-Term Management:

Refer for:

• Electrophysiological study (EPS)

• Radiofrequency ablation of the accessory pathway (definitive cure)

Activity Advice:

• No competitive sports until full cardiology workup

• Avoid AV nodal blockers unless WPW is definitively ruled out or treated

PEARLS FOR JUNIOR DOCTORS:

✅ Always do an ECG even in "just palpitations." WPW might be lurking.

✅ Suspect WPW if young, fit patient has sudden onset tachycardia, especially with syncopal episodes.

✅ Recognize pre-excited AF early — irregularly irregular, wide QRS, very rapid.

✅ NEVER give adenosine or AV nodal blockers if unsure — when in doubt, call for senior help or cardio consult.

✅ Refer all patients with WPW (even if asymptomatic) for cardiology review and risk stratification.