Transesophageal electrophysiological evaluation of children with a history of supraventricular tachycardia in infancy.

Supraventricular tachycardia (SVT) presenting in the neonatal period may resolve by 1 year of age. Predicting which patients require therapy beyond 1 year of age is desirable. Pediatric electrophysiology databases from two institutions were reviewed for patients with a history of infant SVT who underwent transesophageal electrophysiology study (TEEPS) after initial SVT and before 2 years of age. All patients were tested off medications and followed for clinical recurrence. Forty-two patients presented with SVT at median age of 4 days (0-300 days). Initial control was achieved with one drug in 31 patients and multiple drugs in 11 patients. Prior to TEEPS, nine patients had clinical recurrence in the first year of life after initial control had been previously achieved. For all patients, TEEPS was performed, without complications, at median 13 months (9-22 months) of age and at median of 13 months (6-22 months) following the initial SVT episode. SVT was inducible in 27/42: 8 atrio-ventricular nodal reentry tachycardia (AVNRT) and 19 atrio-ventricular reciprocating tachycardia (AVRT). Inducibility was not associated with age at presentation, age at TEEPS, ventricular dysfunction at presentation, presence of structural congenital heart disease, number of drugs required to initially control SVT, or SVT recurrence after initial control. Of 15 not inducible at TEEPS, none had known SVT recurrence off medications at median follow-up of 27 months (6-37 months). In conclusion, among patients having SVT in early infancy, (1) TEEPS results are not associated with clinical variables, (2) non-inducibility is a good indicator of lack of clinical recurrence at intermediate follow-up, and (3) AVNRT may be more prevalent in infancy than previously reported.