From the Guidelines
Wolff-Parkinson-White (WPW) syndrome is a heart condition characterized by an extra electrical pathway between the heart's upper and lower chambers, causing rapid heartbeats and abnormal heart rhythms, with a distinctive pattern on an electrocardiogram (ECG) showing a short PR interval and a delta wave. This congenital condition is diagnosed when ventricular pre-excitation on the resting ECG participates in arrhythmias, as stated in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. Symptoms may include palpitations, dizziness, shortness of breath, fainting, and rarely, sudden cardiac death. Many people with WPW remain asymptomatic until an episode occurs.
The condition occurs because during fetal development, the heart's electrical insulation fails to form properly, creating an accessory pathway called the Bundle of Kent that allows electrical signals to bypass the normal conduction route, creating a circuit for reentrant tachycardia. Treatment options include medication, catheter ablation, or cardioversion depending on symptom severity. Beta-blockers like metoprolol (25-100 mg twice daily) or calcium channel blockers like verapamil (120-360 mg daily) may be prescribed to control heart rate. However, administration of certain medications such as intravenous amiodarone, adenosine, digoxin, or nondihydropyridine calcium channel antagonists in patients with WPW syndrome who have pre-excited AF is potentially harmful because these drugs accelerate the ventricular rate, as warned in the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation 1.
For definitive treatment, catheter ablation has a success rate of over 95% and involves destroying the abnormal pathway using radiofrequency energy, and is considered the safest and most effective treatment option for WPW syndrome, especially in patients with a high risk of sudden cardiac death, as supported by the 2015 ACC/AHA/HRS guideline 1. The risk of sudden cardiac death associated with WPW appears highest in the first 2 decades of life, and increased risk is associated with a history of symptomatic tachycardia, multiple accessory pathways, and a shortest pre-excited R-R interval of <250 ms during AF.
Key points to consider in the management of WPW syndrome include:
- The diagnosis is reserved for patients who demonstrate ventricular pre-excitation on their resting ECG that participates in arrhythmias
- The condition can lead to rapid anterograde accessory pathway conduction during AF, resulting in a risk of sudden cardiac death
- Catheter ablation is the recommended treatment for patients with WPW syndrome, especially those with a high risk of sudden cardiac death
- Certain medications should be avoided in patients with WPW syndrome who have pre-excited AF, as they can accelerate the ventricular rate and increase the risk of sudden cardiac death.
From the Research
Definition and Characteristics of Wolf Parkinson White Syndrome
- Wolf-Parkinson-White (WPW) syndrome is a disorder characterized by the presence of at least one accessory pathway (AP) that can predispose people to atrial/ventricular tachyarrhythmias and even sudden cardiac death 2.
- It is the second most common cause of paroxysmal supraventricular tachycardia in most parts of the world, affecting about 0.1-0.3% of the general population 2.
- Most patients with WPW syndrome have normal anatomy, but it may be associated with concomitant congenital heart disease or systemic diseases 2.
Symptoms and Risks
- Although many individuals are asymptomatic, during supraventricular arrhythmia episodes, they may experience severe symptoms, including syncope or even sudden cardiac death (mainly due to pre-excited atrial fibrillation over rapidly conducting AP) 2.
- In addition to arrhythmia-related symptoms, for some specific locations of the APs with overt anterograde conduction, there might be a reduction in exercise capacity mediated by a reduction in LV systolic performance due to anomalous LV depolarization 2.
Diagnosis and Management
- Although it is typically diagnosed through electrocardiography (ECG), additional tests are necessary for risk assessment 2.
- Management of WPW syndrome may be quite challenging and can vary from only acknowledging the presence of the accessory pathway to pharmacological treatment or radiofrequency ablation 2, 3, 4.
- Catheter ablation is the most effective means of achieving the goal of abolishing symptoms and risk of pre-excited atrial fibrillation 3.
- Medication is often employed in the acute setting to terminate paroxysms of arrhythmia associated with the accessory pathway and reduce the subsequent burden of symptoms until ablation can be performed 3, 4, 5, 6.