Late cure after radiofrequency catheter ablation in a pediatric patient.

A 12-year-old female with the Wolff-Parkinson-White syndrome underwent an electrophysiologic study followed by radiofrequency catheter ablation of the left-lateral accessory pathway. After several unsuccessful attempts, the procedure was stopped because of early recurrence of accessory pathway conduction. Twenty-four hours after the procedure, the patient was found without ventricular pre-excitation pattern on the electrocardiogram. During a 12-month follow-up, the Wolff-Parkinson-White pattern was no longer present. A transesophageal electrophysiologic study showed no further tachycardia induction and the patient is still asymptomatic. This report raises the issue that ablation-induced lesions may evolve considerably during the first few days after ablation, leading to either recurrent accessory pathway conduction or long-lasting complete cure.

Electrophysiological evaluation of asymptomatic ventricular pre-excitation in children and adolescents.

BACKGROUND: Diagnostic assessment and treatment have been described in detail in symptomatic WPW syndrome, but little information exists about significance and prognosis of an incidentally found ventricular pre-excitation (VPE) in asymptomatic children. The aim of the study was to evaluate, retrospectively, the role of electrophysiological study (EPS) in the assessment of the arrhythmic risk in asymptomatic patients with VPE. MATERIAL AND METHODS: Sixty-two asymptomatic children and adolescents (38 M/24 F, aged 9.8+/-5.1 years) referred to our Division between 1996 and 2002 for an incidentally found VPE underwent an EPS for arrhythmic risk stratification. The following parameters were examined: anterograde effective refractory period of the accessory pathway (AP), the 1-to-1 conduction over the AP, the inducibility of atrio-ventricular re-entrant tachycardia (AVRT) and the inducibility of atrial fibrillation (AF) with measurement of minimal RR between two consecutive preexcitated QRS complexes, the average RR interval of all cycles, and the percentage of preexcitated QRS complexes. RESULT: During the EPS, 36 patients (58.1%) experienced sustained SVT. The tachycardia was initiated in the basal state in 22 patients and after isoproterenol in the other 14. Orthodromic AVRT (cycle length 305.9+/-48.5 ms) was recorded in 29 patients. In three patients, both orthodromic and antidromic AVRT were recorded, with different cycle length (CL). Antidromic AVRT alone (CL 239.5+/-13.7 ms) was recorded in four patients. AF was recorded in nine patients: in six patients, it was recorded after the induction of orthodromic or antidromic AVRT, in the other three cases AF was the first and only arrhythmic event. The minimal RR between two consecutive pre-excitated QRS ranged between 250-230 ms (mean 237.5+/-9.6 ms). In the 26 patients who presented no induced sustained tachycardia in the EPS, the 1:1 conduction over the AP ranged between 210 and 600 ms (mean 279.6+/-75.2 ms). CONCLUSIONS: Electrophysiological evaluation remains the gold standard for assessing risk of life-threatening arrhythmias in patients with VPE. However, a high proportion of healthy children and adolescents with VPE can experience sustained AVRT and/or AF during EPS. These results raise questions about the necessity of an aggressive treatment approach to prevent those "rare" cases of sudden death.