Weight <30 kg was found to be an independent predictor of acute success for patients with pediatric Wolff-Parkinson-White undergoing catheter ablation, and associated with a small yet elevated risk of major adverse events, according to a recent study published in JACC: Clinical Electrophysiology.

Christopher M. Janson, MD, et al., evaluated 4,456 cases from 84 centers captured by ACC’s IMPACT Registry, with 14% weighing <30 kg. They found that “subjects weighing <30 kg were more likely to have preprocedural supraventricular tachycardia (SVT) (45% vs. 29%; p<0.001) and more likely to have right septal accessory pathways (25% vs. 33%; p<0.001).” While major adverse events were ultimately rare, a higher rate was identified among the <30 kg cohort (0.3% vs. 0.05%; p=0.04).

Researchers noted no significant difference in the likelihood of deferred ablation between those weighing <30 kg and the rest of the participants (9% vs. 12%; p=0.07) or use of cryoablation (11% vs. 11%; p=0.70) and ablation success was higher in the <30 kg cohort (95% vs. 92%; p=0.009), even after adjusting for accessory pathway type, location and ablation energy source using multivariable modeling. Use of radiofrequency and Cryo catheters and non–left-free wall pathway locations were associated with ablation failure.

Janson, et al., acknowledge that “although [they] expected patient weight to affect intraprocedural decisions and outcomes, [their] analysis suggests that a significant source of variation occurs before the procedure, in patient selection at referral for ablation.” This referral bias led to a higher proportion of patients <30 kg being symptomatic, exhibiting documented SVT and taking medications.

Overall, despite the variation in decision to refer for electrophysiology study, weight <30 kg remained an independent predictor of acute procedural success, with anatomic factors likely playing a role in greater success in smaller patients. This success comes at the cost of higher rates of major adverse events.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias

Keywords: Electrophysiology, Referral and Consultation, Registries, Catheters, Catheter Ablation, Tachycardia, Supraventricular, Accessory Atrioventricular Bundle, Cryosurgery, IMPACT Registry, National Cardiovascular Data Registries

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