WOLFF PARKINSON WHITE SYNDROME

✓ Medically ReviewedDISEASEID: MDBT0173🚨 TRIAGE: EMERGENCYICD-10: I45.6

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Definition

CLINICAL DEFINITION

Wolff-Parkinson-White (WPW) syndrome is a pre-excitation syndrome characterised by the presence of an abnormal accessory electrical conduction pathway between the atria and ventricles, known as the bundle of Kent. It is clinically defined by the triad of a short PR interval, a widened QRS complex with a slurred upstroke (delta wave) on the resting electrocardiogram, and the occurrence of symptomatic tachyarrhythmias, most commonly atrioventricular reentrant tachycardia (AVRT).

IN PLAIN ENGLISH

Wolff-Parkinson-White syndrome is a heart condition where an extra electrical pathway causes the heart to beat too fast. This extra pathway can lead to sudden episodes of a rapid heart rate, which may cause palpitations, dizziness, or shortness of breath.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

WPW syndrome is NOT merely the presence of the WPW ECG pattern (ventricular pre-excitation) in an asymptomatic individual; the syndrome requires the occurrence of symptomatic tachyarrhythmias. It is also distinct from atrioventricular nodal reentrant tachycardia (AVNRT), which uses dual pathways within the AV node rather than an extranodal accessory pathway.

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Word Breakdown

Wolff, Parkinson, White

=Named after Louis Wolff (American cardiologist, 1898-1972), John Parkinson (English physician, 1885-1972), and Paul Dudley White (American cardiologist, 1886-1973) who first described the ECG findings in 1930

-syndrome

=A group of signs and symptoms that occur together and characterise a particular abnormality

Literal Meaning: A condition characterised by the clinical and electrocardiographic features described by Wolff, Parkinson, and White

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Abbreviations

WPW=Wolff-Parkinson-White — most common abbreviation for the syndrome and ECG pattern

AVRT=Atrioventricular reentrant tachycardia — the most common arrhythmia associated with WPW syndrome

AP=Accessory pathway — the abnormal electrical connection characteristic of WPW

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Synonyms & Variants

Pre-excitation syndrome›Ventricular pre-excitation›Anomalous atrioventricular excitation›

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Category-Specific Context

As a Disease, WPW syndrome represents the clinical manifestation of a congenital anatomical variant (the accessory pathway) combined with a propensity for reentrant tachyarrhythmias. It is distinct from the asymptomatic WPW pattern (an ECG Sign), bridging the gap between a structural electrophysiological anomaly and a symptomatic cardiovascular disease requiring risk stratification and potential intervention.

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Clinical Context & Usage

CLINICAL SETTINGS

Cardiology Electrophysiology ClinicEmergency DepartmentPaediatric Cardiology WardGeneral Medicine WardIntensive Care Unit

USAGE & DOCUMENTATION NOTES

Clinicians often use 'WPW pattern' or 'ventricular pre-excitation' to describe the asymptomatic ECG finding (short PR, delta wave) and reserve 'WPW syndrome' for patients who have documented symptomatic tachyarrhythmias. In notes, the location of the accessory pathway (e.g., left-sided vs. right-sided, posteroseptal) is often specified if known from electrophysiology studies or ECG algorithms. The term 'manifest pre-excitation' is used when the delta wave is visible on the resting ECG, as opposed to 'concealed' pathways which only conduct retrogradely and do not show a delta wave.

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Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

WPW syndrome arises from the persistence of an accessory atrioventricular connection, the bundle of Kent, which fails to regress during normal cardiac embryological development. This pathway bypasses the atrioventricular (AV) node, allowing electrical impulses to pre-excite the ventricular myocardium earlier than normal conduction via the His-Purkinje system. Because the accessory pathway typically lacks the decremental conduction properties (rate-limiting delay) of the AV node, it can conduct impulses rapidly, especially during atrial arrhythmias like atrial fibrillation. The most common tachyarrhythmia, orthodromic atrioventricular reentrant tachycardia (AVRT), involves anterograde conduction down the AV node and retrograde conduction up the accessory pathway, forming a macro-reentrant circuit. Antidromic AVRT, which is less common, conducts anterograde down the accessory pathway, resulting in a wide-complex tachycardia.

PRIMARY CAUSES

Congenital persistence of the bundle of Kent

Failure of the fibrous atrioventricular ring to completely insulate the atria from the ventricles during embryogenesis leaves a muscular bridge capable of aberrant electrical conduction.

Ebstein's anomaly

A congenital heart defect characterised by apical displacement of the tricuspid valve leaflets; strongly associated with right-sided accessory pathways, often multiple.

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Epidemiology

Prevalence:The prevalence of the WPW ECG pattern (ventricular pre-excitation) in the general population is estimated at 0.1% to 0.3% (1 to 3 per 1,000 individuals). A smaller proportion of these individuals will develop WPW syndrome (symptomatic arrhythmias), with estimates suggesting that roughly 10% to 30% of those with the ECG pattern will experience symptoms over their lifetime.

Age Group:The WPW ECG pattern is congenital and present from birth, but symptomatic tachyarrhythmias most frequently manifest in childhood, young adulthood (20–40 years), or middle age. Presentation in older adults is less common but can occur.

Sex Predilection:Male

Geographic Distribution:Globally uniform, as it is a congenital developmental anomaly. No specific regional, ethnic, or geographic predilection has been established.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 EMERGENCY

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

Pre-excited atrial fibrillation: an irregular, wide-complex tachycardia in a patient with WPW. Misdiagnosing this as ventricular tachycardia and administering AV node blockers can lead to ventricular fibrillation and sudden cardiac death. Urgent electrical cardioversion is required if haemodynamically unstable.
Asymptomatic WPW pattern in high-risk professions or athletes: requires non-invasive or invasive risk stratification (e.g., exercise testing, Holter, or EPS) to identify pathways with short refractory periods that carry a risk of sudden cardiac death.

URGENT EVALUATION TRIGGERS

Sustained palpitations with haemodynamic compromise (hypotension, altered mental status, chest pain, or acute heart failure) requiring immediate electrical cardioversion.
Irregular, wide-complex tachycardia (suggesting pre-excited atrial fibrillation) requiring urgent antiarrhythmic therapy (e.g., intravenous procainamide) or electrical cardioversion.
Syncope or near-syncope in a patient with a known or suspected WPW pattern, suggesting a high-risk accessory pathway or transient rapid arrhythmia.

Contraindications & Precautions

CONTRAINDICATIONS

AV node-blocking agents (e.g.
adenosine
beta-blockers
non-dihydropyridine calcium channel blockers
digoxin) are contraindicated in patients with WPW syndrome who present with pre-excited atrial fibrillation or flutter
as blocking the AV node may preferentially shunt conduction down the accessory pathway
accelerating the ventricular rate and precipitating ventricular fibrillation.

SPECIAL PRECAUTIONS

Avoid competitive sports or high-intensity exertion in patients with known high-risk accessory pathways (e.g.
shortest pre-excited RR interval < 250 ms during AFib) until definitive risk stratification or ablation is performed.
Use caution with sympathomimetic drugs or agents that shorten the refractory period of the accessory pathway
as they may facilitate reentrant tachycardias.

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Sudden cardiac death — rare but catastrophic
usually resulting from atrial fibrillation conducting rapidly down the accessory pathway
degenerating into ventricular fibrillation.
Tachycardia-induced cardiomyopathy — prolonged or frequent episodes of AVRT or atrial fibrillation can lead to reversible left ventricular dysfunction.
Heart failure — secondary to haemodynamic compromise during sustained rapid tachyarrhythmias or resulting cardiomyopathy.
Stroke or systemic embolism — associated with concurrent atrial fibrillation
though the risk is primarily driven by the AFib itself rather than the accessory pathway.

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Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Wellens' syndrome

Both are eponymous cardiac syndromes associated with specific ECG patterns, but Wellens' syndrome involves T-wave inversions in V2-V3 indicating critical LAD stenosis, whereas WPW involves a delta wave and short PR interval.

Brugada syndrome

Both are eponymous arrhythmogenic syndromes with distinct ECG criteria, but Brugada syndrome involves ST-segment elevation in V1-V3 and carries a risk of sudden cardiac death without an accessory pathway.

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Atrioventricular nodal reentrant tachycardia (AVNRT)

Key Distinguishing Feature: AVNRT uses dual pathways within the AV node, typically lacks a delta wave on the resting ECG, and does not involve an extranodal accessory pathway.

Bundle branch block

Key Distinguishing Feature: Causes a widened QRS complex, but the PR interval is normal and there is no delta wave; the widening is due to delayed intraventricular conduction rather than pre-excitation.

Myocardial infarction

Key Distinguishing Feature: Negative delta waves (Q waves) in WPW can mimic pathological Q waves of an MI, but the PR interval is short in WPW and the clinical context differs.

Ventricular tachycardia

Key Distinguishing Feature: Antidromic AVRT in WPW produces a wide-complex tachycardia that can mimic VT, but AVRT maintains AV association and may show fusion beats or respond to AV node blockade (if not pre-excited AFib).

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Clinical Pearls

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Distinguish between the 'WPW pattern' (the asymptomatic ECG finding of a short PR interval and delta wave) and 'WPW syndrome' (the occurrence of symptomatic tachyarrhythmias). Not all patients with the pattern have the syndrome, and risk stratification is key for asymptomatic individuals.

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In a wide-complex tachycardia, if the rhythm is irregularly irregular, strongly suspect pre-excited atrial fibrillation rather than ventricular tachycardia. Administering AV node-blocking agents in this scenario can be fatal.

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The polarity of the delta wave in different ECG leads can help localise the accessory pathway. For example, a negative delta wave in leads V1-V2 suggests a right-sided or septal pathway, while a positive delta wave in V1 suggests a left-sided pathway.

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Catheter ablation is the first-line definitive treatment for symptomatic WPW syndrome and is increasingly considered for asymptomatic patients with high-risk pathway features or those in high-risk professions (e.g., pilots, competitive athletes).

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Example Usage & SOAP

CLINICAL SENTENCE

"The patient is a 24-year-old male with known Wolff-Parkinson-White syndrome who presented to the Emergency Department with a sudden onset of palpitations and lightheadedness; ECG revealed a regular, narrow-complex tachycardia at 180 bpm, consistent with orthodromic AVRT, which terminated following a successful Valsalva manoeuvre."

IN A SOAP NOTE

S: 28-year-old female with a history of Wolff-Parkinson-White syndrome presents with sudden onset of rapid heart rate, chest tightness, and mild dyspnoea starting 30 minutes ago. O: BP 110/70 mmHg, HR 195 bpm, RR 18, SpO2 98% on room air. ECG shows a regular, narrow-complex tachycardia with no visible P waves. Carotid sinus massage was attempted without effect. A: Paroxysmal supraventricular tachycardia, likely orthodromic atrioventricular reentrant tachycardia (AVRT) secondary to WPW syndrome. Haemodynamically stable. P: Administered adenosine 6 mg rapid IV push followed by 20 mL saline flush. Rhythm converted to normal sinus rhythm within 15 seconds. Post-conversion ECG shows sinus bradycardia at 55 bpm, PR interval 0.10s, and positive delta waves in lateral leads. Referred to electrophysiology for outpatient catheter ablation evaluation.

DIFFERENTIAL DIAGNOSIS CONTEXT

Differential for wide-complex tachycardia in a young patient with WPW: (1) Antidromic AVRT — regular, wide-complex, haemodynamically stable, retrograde P waves may be visible; (2) Pre-excited atrial fibrillation — irregularly irregular, wide-complex, variable morphology, high risk of VF; (3) Ventricular tachycardia — regular, wide-complex, AV dissociation, capture or fusion beats present; (4) SVT with aberrant conduction (e.g., bundle branch block) — regular, wide-complex, but resting ECG between episodes shows normal PR and no delta wave.

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Prognosis

SHORT-TERM OUTCOME

With acute termination of the arrhythmia via vagal manoeuvres, medical therapy, or electrical cardioversion, short-term prognosis is excellent, and patients typically return to normal sinus rhythm without residual haemodynamic deficit.

LONG-TERM PROGNOSIS

Long-term prognosis is excellent following successful catheter ablation of the accessory pathway, which is curative in >95% of cases. In untreated symptomatic patients, the lifelong risk of recurrent tachyarrhythmias persists, and there is a small but significant lifetime risk of sudden cardiac death, particularly in those with high-risk pathway properties (e.g., short refractory period).

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References & Coding

ICD-10 DIAGNOSTIC CODE

I45.6

LITERATURE CITATIONS & GUIDELINES

[1]Brugada J, Katritsis DG, Arbelo E, et al. 2019 ESC Guidelines for the management of patients with supraventricular tachycardia. Eur Heart J. 2020;41(5):525-565.

[2]Page RL, Joglar JA, Caldwell MA, et al. 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia. J Am Coll Cardiol. 2016;67(13):e27-e115.

[3]Cohen MI, Triedman JK, Cannon BC, et al. PACES/HRS expert consensus statement on the management of the asymptomatic young patient with a Wolff-Parkinson-White (WPW, ventricular preexcitation) electrocardiographic pattern. Heart Rhythm. 2012;9(6):1006-1024.

MEDICAL DISCLAIMER — This content is intended for educational purposes and qualified healthcare professionals only. Always refer to current clinical diagnostic criteria, institutional protocols, and official guidelines. Medobo is not responsible for clinical decisions made based on this content.