Ventricular electrical remodelling in children with isolated ventricular septal defects before and after closure

Abstract Background: Children with ventricular septal defects experience chronic left-to-right shunting, resulting in ventricular volume overload and alterations in myocardial electrical properties. Data on ventricular electrical remodelling following closure, particularly regarding closure technique, remain limited. Objectıve: To evaluate ventricular depolarisation and repolarisation indices in children with isolated ventricular septal defects before and after closure and to compare the outcomes of surgical and transcatheter approaches. Methods: This retrospective, single-centre study included 58 children aged 4–18 months who underwent isolated ventricular septal defect closure (transcatheter, n = 25; surgical, n = 33) and 40 age- and sex-matched healthy controls. Standard 12-lead electrocardiograms recorded before the procedure and at six months after closure were analysed. Multiple ventricular depolarisation and repolarisation indices were assessed. Results: Before closure, children with ventricular septal defects demonstrated significant abnormalities in ventricular depolarisation and repolarisation indices compared with healthy controls (all p < 0.05). Following closure, most repolarisation indices improved in both groups. Improvement was more pronounced after transcatheter closure, whereas QT interval and QT dispersion did not significantly improve following surgical closure. At the six-month follow-up, QRS duration remained significantly longer in both interventions than in controls. Conclusion: Children with isolated ventricular septal defects demonstrate subclinical alterations in ventricular depolarisation and repolarisation. Defect closure is associated with substantial improvement in ventricular repolarisation; however, depolarisation abnormalities may persist during mid-term follow-up irrespective of closure technique.