This study aimed to examine practice patterns in the inpatient medical treatment of newborns and infants with supraventricular tachycardia (SVT) using the Pediatric Health Information System (PHIS) database, a large, multi-institutional administrative database. A retrospective examination of pediatric hospital discharge data was performed during the study period from January 2003 to September 2008. Data were extracted from the index hospitalization of all individuals younger than 1 year with the principal discharge diagnosis of SVT. Those with coexisting congenital or acquired structural heart disease were excluded from the study. The analysis included 171 patients. No deaths occurred, and 95 % of the infants were discharged to home. More than half (53 %) of the patients spent a portion of their hospital stay in an intensive care unit (ICU) setting. Multidrug therapy was common, with 45 % of the patients receiving two or more antiarrhythmic agents on the day of discharge. The five most commonly used antiarrhythmic drugs, in order of decreasing frequency of use, were propranolol, digoxin, amiodarone, flecainide, and sotalol. The median hospital stay for the group was 4 days, and this value increased as a function of the number of antiarrhythmic drugs used (median, 7 days for three or more agents) and the need for intensive care (median, 6 days). The information provided in this study helps to define common practice patterns and should allow caregivers to provide meaningful expectations to families regarding their potential treatment course and to anticipate the hospital length of stay.