We report our experience in radiofrequency catheter ablation between April, 1992 and December, 1998, in which we treated 287 parients less than 18 years of age (mean 14.3±3.1 years) with supraventricular tachycardia. Accessory pathways were the arrhythmic substrate in 252 of the patients (87.8%), the patients having a total of 265 accessory pathways. Atrioventricular nodal re-entry was the cause of tachycardia in 26 patients (9.0%), while atrial flutter was detected in the remaining 9 patients (3.1%). We were able successfully to eliminate the accessory pathway in 236 patients (89%), but 25 patients had recurrent arrhythmias. Ablation proved successful in all cases of atrioventricular node re-entry tachycardia, the slow pathway being ablated in 25 patients, and the fast pathway in only one case. Recurrence of the arrhythmia occurred in three patients (11.5%). We performed a second ablation in these children, all then proving successful. The ablation was successful in all cases of atrial flutter, with one recurrence (11.1%). Overall, therefore, ablation was immediately successful in 271 patients (94.4%), with a recurrence of the arrhythmia in 29 cases (10.7%). The incidence of serious complications was 2.09% There was one late death due to infective endocarditis, 3 patients suffered complete heart block, 1 had mild mitral regurgitation, and 1 patient developed an haematoma in the groin. We conclude that radiofrequency catheter ablation can now be considered a standard option for the management of paroxysmal supraventricular tachycardias in children and young adults.

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.