Induction of sustained ventricular tachycardia after surgical repair of tetralogy of Fallot

Between 1980 and 1996, 89 unselected consecutive patients with repaired tet ralogy of Fallot (TOF) underwent examination, including a prospective right ventricular programmed stimulation with the same protocol (S-1, S-2, S-3, S-4). Age at surgery was 4.2 +/- 3.5 years and age at electrophysiologic st udy was 10.9 +/- 6.5 years. Follow-up since surgery was 14.4 +/- 4.8 years and patient follow-up after programmed stimulation was 7.8 +/- 4.2 years. T he aim of this study was to evaluate the main predictors of the inducibilit y of a sustained monomorphic ventricular tachycardia (VT) and its significa nce to identify a group of patients at risk of sudden death: 21 (group A) h ad and 68 (group B) had no induced sustained VT. The induction of VT was re lated to older age at programmed stimulation, prolonged QRS duratian, prese nce of complex ventricular arrhythmia, symptoms, right ventricular overload , and increased right ventricular systolic pressure. Predictors of induced VT selected by multivariate analysis were age at electrophysiologic study ( p <0.0001), previous palliative shunts (p <0.001), right ventricular systol ic pressure (p <0.007), and symptoms (p <0.005). Among group A patients, 4 had previous sustained VT before stimulation, and 1 had sustained VT only d uring follow-up after stimulation. No patients of group B had clinical sust ained VT. Late mortality was low but similar between bath groups. A negativ e electrophysiologic study may be helpful for the management of patients af ter surgical repair of TOF; but because the arrhythmic event rate is low, t he findings of even a positive electrophysiologic study should be interpret ed with caution. (C) 1999 by Excerpta Medico, Inc.