Background: The aim of this study was to evaluate the indications, results and complicationsof radiofrequency ablation (RFA) and transcatheter cryoablation (TCA) in neonates andinfants with incessant drug-resistant supraventricular tachycardia (SVT).

Methods: Out of 225 patients who underwent RFA and TCA at our center between January2010 and February 2012, 5 patients under the age of 1 (4 male, 1 female) were evaluated. Theindication for RFA/TCA was recurrent hemodynamically compromising drug-resistant SVT.

Results: Over a 2-year period, 6 ablation procedures were performed in 5 patients. Averagepatient age was 3.3 ± 3.9 months (12 days – 9.5 months); average patient weight was 5.4 ± 2.2 kg (3.5–9 kg). One patient had ventricular septal defect, 1 had corrected transposition of great arteries, ventricular septal defect, right ventricular hypoplasia and pulmonary hypertension, while 3 had only patent foramen ovale. Electrophysiology study showed 1 accessory pathway in each patient (right posteroseptal in 2, left posteroseptal in 2 and left lateral in 1). The pathway was manifest in 1 patient with Wolff-Parkinson-White syndrome (WPW) andconcealed in the rest. Two of the concealed pathways had slow conduction time and decremental properties (the permanent form of junctional reciprocating tachycardia). Two patients underwentTCA and 3 — RFA, with an acute success rate of 100%. In the first week after the procedure, the patient with the complex cardiac anomaly and WPW developed recurrence and under went ablation again. Four of the procedures were carried out using an electroanatomic mapping system besides fluoroscopy. Average procedure time was 167 min (100–234); fluoroscopy time was 8.2 min (0.7–19.7). None of the patients developed major complications. After the average follow-upperiod of 6.5 months (3–18), all patients were symptom-free without medication.

Conclusions: RFA and TCA can be performed successfully in neonates and infants within cessant medically refractory SVT.