[Supraventricular tachycardia in infants and children]

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

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

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.

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.

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.