[Supraventricular tachycardia in infants and children].

INTRODUCTION: Supraventricular tachycardia (SVT) is the second most frequent form of arrhythmia in pediatrics after extrasystole.

OBJECTIVES: 1. To determine the clinical characteristics and treatment of SVT in infants and children. 2. To determine treatment response and the drugs used.

METHOD: A retrospective review of 61 cases of SVT requiring PICU admission (1999-2004) was performed. PICU admission was due to persistent SVT after vagal maneuvers.

RESULTS: There were 61 patients and 39 were boys (63.9%). The mean age was 2.1 years (SD +/- 3.1). Twelve patients had congenital heart disease (19.7%); three (4.9%) were admitted after heart surgery, and the remaining patients had no antecedents (60.7%). The mean cardiac frequency was 238 beats/min (SD +/- 42.86). Heart failure (HF) was observed in 14 patients (23%). Statistically significant differences were found between the presence of HF and time since onset (p < 0.01) and younger age (p < 0.01). The most frequent diagnosis was SVT due to re-entry in 28 patients (45.9%). Medical treatment was required in 46 patients (75.4%) and response was achieved in 35 (57.4%). At crisis the first drug used was adenosine triphosphate (ATP) in 35 patients (61.4%) with good response in 21 (36.8%). As maintenance therapy digoxin was used in 29 patients (50.9%) without relapses in 22 (78.6%). Radiofrequency ablation was required in 17 patients (27.9%), and there were three relapses (17.6%). The ages of patients who underwent ablation ranged from 3.5 days to 13 years.

CONCLUSIONS: 1. HF was observed mainly in infants. 2. Most of the patients had good response to ATP therapy. 3. Radiofrequency ablation was mainly required in patients aged more than 1 year.