Intermittent versus Persistent Wolff-Parkinson-White Syndrome in Children: Electrophysiologic Properties and Clinical
Michelle E Kiger1, Anthony C McCanta2, Suhong Tong3
1Department of Pediatrics, University of Colorado, Denver, Colorado.
Insights
Intermittent Wolff-Parkinson-White syndrome in children shows similar risks to persistent forms, challenging previous assumptions. Further research is needed to understand outcomes like sudden death in pediatric WPW patients.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Cardiac Arrhythmias
Background:
- Intermittent Wolff-Parkinson-White (WPW) syndrome is often perceived as lower risk for sudden cardiac death.
- Limited data exists on the electrophysiologic (EP) characteristics and natural history of intermittent WPW specifically in pediatric populations.
Purpose of the Study:
- To compare the electrophysiologic characteristics and clinical outcomes of pediatric patients with intermittent WPW versus persistent WPW.
- To evaluate the risk stratification of accessory pathways (APs) in children with different WPW presentations.
Main Methods:
- A retrospective review of 295 WPW patients aged 1-18 years (1996-2013).
- Patients were categorized into intermittent preexcitation, loss of preexcitation on Holter/exercise, or persistent preexcitation groups.
- High-risk accessory pathways were defined by effective refractory period (APERP), block cycle length, or shortest preexcited RR interval during atrial fibrillation ≤250 ms.
Main Results:
- No significant difference in symptoms was observed between the groups.
- Intermittent WPW showed a significantly longer median APERP compared to persistent WPW and loss of preexcitation groups (380 ms vs. 320 ms and 310 ms, respectively).
- High-risk pathways were more frequent in the loss of preexcitation group when isoproterenol values were included (54% vs. 16% persistent, 11% intermittent). One death and one resuscitation event occurred in patients with loss of preexcitation and persistent WPW, respectively.
Conclusions:
- Intermittent preexcitation in pediatric WPW does not indicate a lower risk based on EP criteria or reduced symptoms.
- The incidence of preexcited atrial fibrillation and sudden death in pediatric WPW is low, necessitating larger studies for definitive conclusions.
Background:
Intermittent Wolff-Parkinson-White (WPW) syndrome is considered to have a lower risk of sudden death. Fewer data exist regarding electrophysiologic (EP) characteristics and the natural history of intermittent WPW in children.
Methods:
All patients with WPW age 1-18 years at a single institution (1996-2013) were reviewed. Patients with intermittent preexcitation were compared to those with loss of preexcitation on Holter/exercise testing and those with persistent preexcitation. High-risk accessory pathway (AP) was defined as AP effective refractory period (APERP), block cycle length, or shortest preexcited RR interval during atrial fibrillation ≤250 ms.
Results:
A total of 295 patients were included: 226 (76.6%) persistent, 39 (13.2%) intermittent, and 30 (10.2%) loss of preexcitation Holter/exercise. There were no differences in symptoms between groups. Median interquartile range APERP was significantly longer in intermittent WPW (380 [320, 488] ms vs 320 [300, 350] ms persistent, 310 [290, 330] ms loss of preexcitation Holter/exercise; P = 0.0008). At baseline, there was no difference between groups in frequency of high-risk pathways. However, when isoproterenol values were included, high-risk pathways were more frequent among patients with loss of preexcitation on Holter/exercise (54% vs 16% persistent, 11% intermittent; P = 0.005). There was one death in a patient with loss of preexcitation on exercise testing, no EP study, and prior drug use. A second patient with persistent WPW and APERP 270 ms required resuscitation following a methadone overdose.
Conclusion:
Intermittent preexcitation in children does not connote a lower risk AP by EP criteria or reduced symptoms. The low number of pediatric WPW patients who develop preexcited atrial fibrillation or sudden death warrants larger studies to investigate these outcomes.
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