This study evaluated the clinical characteristics and acute and maintenance treatment of 62 newborns with arrhythmia treated in the neonatal intensive care unit (NICU) between January 2003 and December 2024. Arrhythmia incidence among NICU admissions was 0.4%. Mean gestational age, birth weight, and age at diagnosis were 37 weeks, 3117 g, and 6.2 days, respectively. Echocardiographic findings were present in 54.8%, including ventricular septal defect, total anomalous pulmonary venous return, pulmonary stenosis, mitral valve thrombus, myocardial dysfunction, and heart failure. Supraventricular tachycardia (SVT) was the most common arrhythmia. One antenatally diagnosed fetal arrhythmia case had hydrops fetalis, and SVT was terminated postnatally by vagal maneuver. Acute antiarrhythmic therapy was administered to 56.5%, while 43.6% required no medication. At discharge, 27 (43.5%) received maintenance therapy, most commonly amiodarone plus propranolol. Five patients underwent invasive cardiac evaluation and two underwent cardioversion. No arrhythmia-related mortality occurred, supporting individualized diagnostic and therapeutic approaches.

Keywords: newborn, arrhythmia, supraventricular tachycardia, neonatal intensive care unit, hydrops fetalis