Catheter ablation in children with supraventricular tachycardia mediated by accessory pathways—use of radiofrequency current as a first line of therapy

Catheter ablation of an accessory atrioventricular pathway using 500 kHz radiofrequency current was attempted in 53 children and young adolescents less than 16 years of age (mean 9.3±4.1 years) who were referred for treatment of symptomatic supraventricular tachycardia. Thirty children had the Wolff-Parkinson-White syndrome and 23 had tachyarrhythmias related to an accessory pathway conducting only in retrograde fashion. Of the latter, seven were found to have the permanent form of junctional reciprocating tachycardia, which had resulted in depressed left ventricular function in four. Ablation of left-sided accessory pathways was usually attempted utilizing an arterial approach to the annulus of the mitral valve, while the venous route to the atrial aspect of the tricuspid valvar annulus was chosen for right-sided accessory connections. To reduce invasiveness and the duration of the procedure, a technique with a solitary catheter was attempted in 20 children with the Wolff-Parkinson-White syndrome, regardless of the anatomical site of the accessory pathway. Ablation of 54 of 56 accessory connections was achieved in 51 patients (96% success) with a median of six applications of radiofrequency current. The sessions were completed within 3.4±2.2 hours, with a median exposure to radiation of 31.1 minutes. During a 10-month period of follow- up, no patient required antiarrhythmic medication, and 51 children (96%) were completely free of any symptoms related to arrhythmias. Left ventricular function returned to normal in the four children with tachycardia-induced cardiomyopathy. Except for a patient with an arterial thrombotic occlusion, no serious complications were encountered. Catheter ablation using radiofrequency current is a highly effective and safe curative approach for treating young patients with supraventricular tachycardias mediated by accessory pathways. The use of fewer catheters of smaller size is feasible and advisable in this cohort of patients.