HIGH PREVALENCE OF REPOLARIZATION ABNORMALITIES IN CHILDREN WITH SIMPLE VENTRICULAR ECTOPY

Background: Premature ventricular contractions (PVCs) may occur in 0.3 to 2.2% of routine resting electrocardiograms (ECGs) in children with structurally normal hearts. Hypothesis: This study tests the hypothes is that repolarization abnormalities are present more frequently on th e surface ECG in pediatric patients with benign ventricular ectopy. Me thods: A retrospective study was performed examining 32 children with benign ventricular ectopy and structurally normal hearts. The surface ECG was carefully reviewed, concentrating on repolarization abnormalit ies as evidenced by a prolonged QTc, a prolonged JTc, and/or an abnorm al T-wave vector. QTc was calculated using Bazett's formula and consid ered prolonged if > 440 ms, and the JTc was calculated using a formula analogous to Bazett's formula and considered prolonged if > 340 ms. T he T-wave vector was considered normal if between 0 to + 90 degrees, c oncordant with the frontal QRS axis and within 60 degrees of the QRS a xis. There were 13 females (41%) and 19 males (59%) with an average ag e of 9.1 years (range 1-16.1 years). These patients were then compared with age- and gender-matched controls. Fourteen of 32 study patients (44%) and 2 of 32 controls (6%) had evidence of repolarization abnorma lities. Results: Using chi(2) analysis, there was a significant differ ence between groups (p = 0.0005). No patient had an abnormal T-wave ve ctor and there were no other significant ECG abnormalities. There was no significant relationship between repolarization abnormalities and p atient gender or age. Conclusion: A significant percentage (44%; p = 0 .0005) of children with benign ventricular ectopy have associated repo larization abnormalities as evidenced by a prolonged QTc and/or JTc. T his finding suggests that children with ''benign PVCs'' may have repol arization changes indicative of underlying substrate abnormalities.