ABSTRACT
INTRODUCTION: The majority of children presenting with paroxysmal supraventricular tachycardia (SVT) have either accessory-pathway-mediated tachycardia or AV node reentry tachycardia. The purpose of this study is to report an unusual mechanism of SVT found in children with structurally normal hearts. METHODS AND RESULTS: Records of all patients undergoing an electrophysiology study (EPS) at our institution between 2000 and 2004 were reviewed to identify those with nonautomatic focal atrial tachycardia (NAFAT). Five patients (three males) with an average age of 13.8 years (median 15 years, range 7-18 years) were identified. All presented with paroxysmal palpitations. They all had structurally normal hearts. At EPS, SVT was reproducibly induced with programmed atrial stimulation (single, double, or triple extrastimuli) in all patients. The average cycle length was 276 +/- 9 ms. Adenosine terminated SVT in 2. A 3-D electro-anatomical system mapping was used in all cases. The right atrium (RA) was mapped in all and the left in two. Foci were mapped to the posterior high RA, lateral RA, lower mid RA septum, inferior to the sinus node, and in the right and left posteroseptal areas. Average number of radiofrequency lesions placed was 8.6 +/- 5. The success rate was 80%; there was one late recurrence. No procedural complications were observed. CONCLUSIONS: NAFAT is a rare form of tachycardia that should be considered in the differential diagnosis of children presenting with SVT. It is amenable to mapping and radiofrequency ablation.