Is Wolff-Parkinson-White (WPW) pattern type A dangerous in youth?

Is WPW Pattern Type A Dangerous in Youth?

Type A Wolff-Parkinson-White (WPW) pattern can be dangerous in youth, particularly when associated with certain high-risk features, and requires appropriate risk stratification and management to prevent life-threatening events.

Understanding WPW Pattern and Risk

• WPW pattern occurs in up to 1 in 250 young athletes and affects approximately 0.1-0.3% of the general population 1, 2
• The presence of an accessory pathway can predispose youth to sudden cardiac death because rapid conduction of atrial fibrillation across the accessory pathway can result in ventricular fibrillation 1
• Young patients with WPW may experience life-threatening events without prior symptoms or markers of high risk on electrophysiological studies 3

Risk Factors for Sudden Cardiac Death in Youth with WPW

• Male sex, presence of Ebstein's anomaly, multiple accessory pathways, and inducible atrial fibrillation are significant risk factors for life-threatening events 3
• Rapid anterograde conduction through the accessory pathway (shortest pre-excited RR interval ≤250 ms) is a critical risk marker 1, 3
• The mean age at life-threatening events is approximately 14.1 years, with 65% of these events being the first symptom of the condition 3

Risk Stratification

• Non-invasive risk assessment should begin with an exercise stress test, where abrupt, complete loss of pre-excitation at higher heart rates suggests a low-risk accessory pathway 1
• Echocardiography should be performed due to the association of WPW with Ebstein's anomaly and cardiomyopathy 1, 4
• Intermittent pre-excitation during sinus rhythm on a resting ECG is consistent with a low-risk pathway 1
• If non-invasive testing cannot confirm a low-risk pathway, an electrophysiological study should be considered to determine the shortest pre-excited RR interval during atrial fibrillation 1

Management Recommendations

• Catheter ablation is recommended for patients with WPW syndrome who have been resuscitated from sudden cardiac arrest due to atrial fibrillation and rapid conduction over the accessory pathway causing ventricular fibrillation 1
• Ablation should be considered in patients with WPW syndrome who are symptomatic and/or who have accessory pathways with refractory periods ≤240 ms in duration 1
• For asymptomatic children with WPW pattern, risk stratification through transesophageal programmed stimulation may be useful to determine management approach 4
• Some physicians may choose to subject all competitive athletes involved in moderate or high-intensity sport to electrophysiological studies regardless of exercise test results 1

Special Considerations for Youth

• Avoid AV nodal blocking agents (digoxin, diltiazem, verapamil, beta-blockers) in patients with pre-excited atrial fibrillation, as they can increase ventricular response rate and potentially precipitate ventricular fibrillation 4
• Adenosine should be used with caution as it may produce atrial fibrillation with a rapid ventricular rate in pre-excited tachycardias 4
• Intermittent pre-excitation is not uncommon in newborns and infants and suggests a lower risk of sudden death 4

Monitoring and Follow-up

• ECG monitoring is recommended for patients with arrhythmias complicating WPW syndrome with rapid anterograde conduction over an accessory pathway until definitive therapy (usually ablation) is established 1
• Long-term surveillance may still be needed after ablation as it will not necessarily prevent the occurrence of atrial fibrillation, especially in older patients 4
• For young athletes with WPW, pre-participation screening should be considered, with special attention to symptoms like palpitations or syncope 1

Common Pitfalls and Caveats

• A significant proportion (37%) of patients who experience life-threatening events do not have high-risk characteristics on electrophysiological studies 3
• The risk of sudden death in WPW syndrome is approximately 0.15-0.5% per year, which though relatively low, represents a significant concern given the young age of affected individuals 1, 4
• Type A WPW (left-sided pathway) is not inherently more or less dangerous than other types; risk is determined by the electrophysiological properties of the pathway rather than its location 1, 3