To evaluate whether landiolol combined with amiodarone improves heart rate and rhythm control compared to amiodarone alone in paediatric patients with postoperative junctional ectopic tachycardia after surgery for congenital heart defect.

We retrospectively identified 24 cases of junctional ectopic tachycardia among 962 children who underwent surgery for congenital heart defects at the German Paediatric Heart Centre between January 2022 and June 2024. Patients received either amiodarone monotherapy or a combination of landiolol and amiodarone. Time to heart rate control and rhythm normalisation, haemodynamic stability, and adverse events were assessed.

Patients who received amiodarone and landiolol achieved faster heart rate control than patients who received amiodarone alone (median 6.7 vs. 14.7 h, p = 0.02, Cohen’s d = 1.05; large effect). Among patients who received landiolol first, control was reached even earlier (2.4 vs. 8 h, p = 0.05, Cohen’s d = 1.49; very large effect). A significant heart rate reduction occurred within 40–120 min after landiolol initiation (mean difference: −23.7 bpm, 95% CI: −45.4 to −1.9, p = 0.04, r = 0.45; medium effect), while no significant effect was observed in patients who received amiodarone alone. Haemodynamic parameters remained stable, although hypotension requiring discontinuation occurred in 11.1% of Landiolol-treated patients.

In this retrospective analysis, combined landiolol and amiodarone therapy demonstrated a shorter time to heart rate control compared to amiodarone alone, especially when landiolol was initiated first. These findings require confirmation in prospective studies.