Our knowledge of the natural history of infants with SVT is incomplete, both in terms of the need for chronic therapy and the duration. Despite the fact that the risk of recurrence is not known (and may be <50%), due to the potential for serious adverse outcomes, most pediatric cardiologists advocate chronic therapy after an infant presents with SVT. The early clinical course can be variable, but most patients do not require medical therapy beyond the first few months of life [7, 20]. The duration of therapy has ranged over the studies but currently lasts 6 to 12 months after presentation [6, 9] because of the uncertainties of the clinical course [20, 24, 25]. The risk of recurrence during the first year of life has not been determined definitively.