Clinical Characteristic Comparison of Neonatal Paroxysmal Supraventricular Tachycardia and Atrial Flutter

Paroxysmal atrioventricular re-entry supraventricular tachycardia (SVT) and atrial flutter (AFL) represent the two most common neonatal tachyarrhythmias. While treatment options have advanced, clinical experience with these conditions remains limited in neonatal populations. This retrospective observational study compared the clinical characteristics, management approaches, and outcomes of SVT and AFL in neonates to optimize clinical decision-making. We analyzed medical records of 43 neonates (23 SVT, 20 AFL) diagnosed over a 7-year period, including prenatal findings, clinical presentation, diagnostic workup, therapeutic interventions, and follow-up data. Our results demonstrate that SVT was characterized by significantly higher ventricular rates (p < 0.01), greater incidence of heart failure (34.8% vs 15.0%, p = 0.04), and more frequent recurrences (39.1% vs 5.0%, p = 0.01) compared to AFL. AFL cases were more frequently detected during fetal monitoring (45.0% vs 13.0%, p = 0.02) and presented earlier postnatally (median 1 vs 3 days, p = 0.03). Both arrhythmias responded effectively to pharmacotherapy, with propafenone demonstrating a dose-dependent reduction in SVT recurrence (p = 0.04). Among 34 patients with follow-up data (17 SVT, 17 AFL), all AFL cases and 70.6% of SVT cases (12/17) maintained sinus rhythm without long-term prophylaxis. These findings suggest distinct clinical profiles between neonatal SVT and AFL. While AFL rarely recurs post-conversion, SVT management should incorporate individualized risk assessment for recurrence when considering long-term prophylaxis.