Event Risk in Children With WPW Syndrome
Is it possible to identify children with Wolff-Parkinson-White (WPW) syndrome who are at risk of life-threatening events?
In this multicenter, retrospective study (1990-2016), cases of children with WPW syndrome who had experienced a life-threatening event (LTE) were compared with controls undergoing electrophysiologic study (EPS) for WPW syndrome. A LTE was defined as sudden death, aborted sudden death, or rapid conduction over the accessory pathway (AP) during atrial fibrillation (AF) with symptoms (e.g., syncope or seizure) or with the shortest pre-excited RR interval (SPERRI) during AF ≤250 ms. During EPS, a SPERRI, an AP effective refractory period, or the shortest paced cycle length with pre-excitation during atrial pacing ≤250 ms was considered high-risk.
The investigators collected data from 96 cases and 816 controls. Arrhythmic symptoms were present in 60% of the former and 84% of the latter prior to the LTE or EPS (p < 0.0005). Among the cases, the mean age at the time of the event was 14 years, and the LTE was the presenting symptom among 62 patients (65%). Full or near-full recovery was noted in 82 (85%) of the cases, whereas recovery with neurological deficit was noted in five (5%) patients, and death in nine (9%) patients. While EPS-derived high-risk features were more likely to be present among the cases, there was considerable overlap of these values among cases and controls. Approximately one-third of the cases would have been considered low-risk if only EP data were used.
The authors concluded that children may experience potentially life-threatening complications of WPW syndrome in the absence of prior symptoms and “high-risk” features at EPS.
WPW syndrome may be a cause of sudden death in a small percentage of patients. The risk of severe symptoms and death is more pronounced in the young, typically individuals in their teens or younger years. Given that these young people are otherwise healthy, and that the AP may be eliminated with a favorable risk-benefit ratio, electrophysiologists have attempted to identify high-risk patients before a LTE. The classic literature suggested a conservative approach in patients with electrocardiographic evidence of WPW, but without symptoms. More recent data revealed that outcomes may be better predicted by EPS-derived parameters than symptom status. Currently, an EPS evaluation is considered a Class IIa indication in such individuals in whom noninvasive testing is inconclusive, for the purposes of risk-stratification and possible ablation. The fact that the majority of children with a LTE in the current study lacked prior symptoms provides rationale for such an approach. The study, however, also underscores the lack of sensitivity of EP-derived data in predicting risk.
Keywords: Accessory Atrioventricular Bundle, Adolescent, Arrhythmias, Cardiac, Atrial Fibrillation, Death, Sudden, Electrocardiography, Electrophysiology, Pediatrics, Pre-Excitation Syndromes, Risk, Seizures, Syncope, Secondary Prevention, Wolff-Parkinson-White Syndrome
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