Supraventricular tachycardia in infancy - Evaluation, management, and follow-up

Background: Supraventricular tachycardia (SVT) occurs frequently in infancy . However, some infants have no recurrences after the initial presentation of SVT, and approximately 30% of infants lose SVT inducibility by 1 year of age. Objective: To determine whether features at presentation, tachycardia chara cteristics, or data from an esophageal electrophysiology (EP) study could p redict which infants will not require antiarrhythmic medication and which i nfants will not have inducible SVT at 1 year. Design: Clinical add tachycardia characteristics at presentation of SVT and data obtained from an esophageal EP study were evaluated prospectively. Pa tients were followed up for 1 year, and an esophageal EP study was performe d to evaluate for continued SVT inducibility. Setting: Primary Children's Medical Center is a tertiary care hospital affi liated with the University of Utah that provides primary care to local pati ents and is a referral center for a 4-state region. Patients: All infants aged 3 months or younger who presented with SVT betwe en August 1995 and October 1997 were evaluated. Interventions: An esophageal EP study was performed at diagnosis and at 1 y ear. Results: The SVT was controlled in all 33 infants. At the initial esophagea l EP study, the mechanism of SVT was atrioventricular node reentry in 5 pat ients (15%) and orthodromic reciprocating tachycardia via an accessory atri oventricular connection in 28 patients (85%). One infant was lost to follow -up, 5 never required medication, 11 had SVT controlled with propranolol hy drochloride, 10 had SVT controlled with amiodarone, and 6 required more tha n 1 medication. Of the 21 patients who have reached 1 year of age, 16 (76%) were not taking any medication and were free of SVT at the time of follow- up. All 16 patients without clinical SVT have undergone a follow-up esophag eal EP study, and 11 of 16 had inducible SVT on esophageal EP study. Thus, of the 21 one-year-old patients, 5 (24%) no longer had clinical or inducibl e SVT. Conclusions: Control of SVT was possible in all patients. Clinical episodes of SVT were uncommon after discharge, yet most still had inducible SVT at 1 year of age. No data at presentation or initial esophageal EP study were predictive of the clinical course or of continued SVT.