Frequency of recurrence among infants with supraventricular tachycardia and comparison of recurrence rates among those with and without preexcitation and among those with and without response to digoxin and/or propranolol therapy.

Approximately 60% of children with supraventricular tachycardia (SVT) develop their initial episode by 1 year of age. Despite resolution in most of these patients by 1 year, approximately 30% of the SVT will recur. We performed a retrospective review of all patients <1 year of age with SVT between January 1984 and December 2000. Recurrence was defined as documented SVT at >1 year of age. Patients were divided into: (1) a first line (FL) group (controlled with digoxin and/or propranolol) and (2) a second line (SL) group (requiring additional antiarrhythmics). The groups were divided based on the presence of preexcitation. The FL group included 116 patients, 20 of whom (17%) had Wolff-Parkinson-White (WPW) syndrome. The SL group included 34 patients, 21 of whom (62%) had WPW (p <0.001). Recurrence of SVT occurred in 32 patients (28%) in the FL group and in 23 patients (68%) in the SL group (p <0.001). SVT recurred in 36 of 41 patients (88%) with WPW compared with 19 of 109 patients (17%) without WPW syndrome (p <0.001). Logistic regression analysis demonstrated that the presence of WPW syndrome was associated with a 29-fold higher odds of SVT recurrence (p <0.001), and that patients with WPW syndrome were more likely to require additional antiarrhythmic therapy (p <0.001). Thus, patients with WPW syndrome who had SVT at <1 year of age have 29-fold higher odds of recurrence at >1 year of age versus those patients with preexcitation. These patients are also more likely to require additional antiarrhythmic therapy to control SVT. Furthermore, children with WPW syndrome who are refractory to treatment with digoxin and/or propranolol are at increased risk of SVT recurrence.