WPW

Question 1

A 40-year-old man presents to the emergency department after a transient loss of consciousness. He was jogging in the park when he suddenly felt palpitations, lightheadedness, and collapsed. Upon regaining consciousness, he felt slightly fatigued but otherwise returned to his baseline within minutes. He denies chest pain, confusion, urinary incontinence, or tongue biting. The patient reports consuming caffeine and energy drinks earlier that morning. He has no significant past medical history and is not taking any medications. In the emergency department, his blood pressure is 118/72 mm Hg, and his pulse is 96/min. Physical examination shows a small abrasion on his knee. Cardiovascular examination reveals normal heart sounds with a regular rhythm. Neurologic examination is unremarkable.

Which of the following is the most likely cause of this patient’s syncope?

A) Vasovagal syncope
B) Orthostatic hypotension
C) Tachyarrhythmia
D) Seizure
E) Acute coronary syndrome

Answer 1

C) Tachyarrhythmia

Although patients with a WW pattern on ECG can be asymptomatic, some develop tachyarrhythmias; the combination of WW findings on ECG and symptomatic tachyarrhythmia constitutes WW syndrome. Paroxysmal supraventricular tachycardia is the most common arrhythmia; it is usually a regular, narrow complex tachycardia. If patients with WW develop atrial fibrillation, they can conduct down the accessory pathway from the atria to the ventricles at a very fast rate, commonly resulting in syncope. This patient’s ingestion of energy drinks, a known precipitant of atrial fibrillation, likely placed him at risk for such a scenario. Alcohol can can also act as a cardiac irritant and promote tachyarrhythmia or atrial fibrillation.

Question 2

What is WPW Syndrome?

Answer 2

A preexcitation syndrome caused by an accessory pathway (Bundle of Kent) that bypasses the AV node, leading to early ventricular depolarization.

Question 3

Is WPW Syndrome congenital or acquired?

Answer 3

Congenital. It is due to an accessory conduction pathway present from birth.

Question 4

WPW Syndrome: How common is it?

Answer 4

It occurs in approximately 0.1-0.3% of the population.

Question 5

What are the ECG findings with WPW Syndrome?

Answer 5

Shortened PR interval (<120 ms), delta wave (slurred upstroke of QRS), and widened QRS complex that is greater than 120 ms (three small boxes).

Question 6

In WPW Syndrome, what is the accessory pathway called?

Answer 6

The Bundle of Kent.

Question 7

What are the common symptoms in WPW Syndrome?

Answer 7

Palpitations, syncope, dizziness, and in severe cases, sudden cardiac death.

Question 8

What arrhythmias are associated with WPW Syndrome?

Answer 8

Atrial fibrillation, atrioventricular reentrant tachycardia (AVRT), and rarely, ventricular fibrillation.

Question 9

What is the risk of sudden cardiac death in WPW?

Answer 9

The risk is increased in patients with rapid conduction through the accessory pathway.

Question 10

What is the most dangerous complication in WPW Syndrome?

Answer 10

Ventricular fibrillation, which can result in sudden cardiac death.

Question 11

What is the overall risk of death in patients with WPW?

Answer 11

The overall incidence of sudden cardiac death in patients with Wolff-Parkinson-White (WPW) pattern on ECG is low (<1%), but the risk is significantly increased in patients with episodes of tachyarrhythmia. Tachyarrhythmia due to atrial fibrillation is especially dangerous because impulses can conduct from the atria to the ventricles at a very fast rate, potentially causing rhythmic degeneration to ventricular fibrillation.

Question 12

How is WPW Syndrome diagnosed?

Answer 12

Often prompted by symptoms, followed by ECG findings and sometimes confirmed with electrophysiological studies.

Question 13

In WPW Syndrome, what is the key risk in atrial fibrillation?

Answer 13

Rapid ventricular response, which can lead to ventricular fibrillation.

Question 14

In the acute setting for WPW, what is the management for any unstable arrhythmia?

Answer 14

Synchronized Cardioversion.

Question 15

For WPW Syndrome, what is the acute management for AVRT?

Answer 15

Vagal maneuvers or IV adenosine as first-line treatment.

Question 16

Specifically for WPW Syndrome, what is the acute management for atrial fibrillation?

Answer 16

Use of procainamide or ibutilide. Avoid AV node blockers like beta-blockers, calcium channel blockers, and digoxin.

Question 17

What is the definitive treatment for WPW Syndrome?

Answer 17

Radiofrequency catheter ablation of the accessory pathway.

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Catheter ablation is the recommended therapy in patients with WW syndrome. It has a nearly 90% efficacy rate and <5% risk of complications, replacing surgical ablation as the preferred treatment for accessory pathways. The need for catheter ablation in asymptomatic patients with WPW patter on ECG is controversial; ablation is sometimes favored in young patients, but observation is often favored in older patients who have demonstrated a relatively longer symptom-
free period.

Question 18

Why are AV node blockers avoided in atrial fibrillation for WPW Syndrome?

Answer 18

Blocking the AV node can increase conduction through the accessory pathway, leading to ventricular fibrillation.

Question 19

What are the lifestyle interventions used to mitigate symptoms in patients with WPW syndrome?

Answer 19

Patients with WPW should be advised to avoid triggers like excessive caffeine, energy drinks, and alcohol, as these can precipitate dangerous arrhythmias. Education on recognizing early symptoms of arrhythmia and seeking prompt medical care is essential for these individuals.