Background: Inappropriate sinus tachycardia (IST) in children and adolescents is an
under recognized autonomic disorder characterized by a persistently elevated heart
rate, often leading to palpitations, fatigue, and impaired quality of life. Conventional
pharmacologic therapies, such as beta-blockers and ivabradine, are frequently limited
by incomplete efficacy or adverse effects. Omega-3 polyunsaturated fatty acids
(PUFAs) have been proposed as a safe adjunctive therapy due to their autonomic and
antiarrhythmic properties. Objective: This systematic review aimed to evaluate the
evidence on omega-3 supplementation for heart rate control, heart-rate variability
(HRV), and clinical outcomes in pediatric IST. Methods: Following PRISMA 2020
guidelines, a systematic search of PubMed, Scopus, Web of Science, and Cochrane
Library was conducted (2015–2025). Eligible studies included randomized controlled
trials, cohort studies, case–control studies, and systematic reviews/meta-analyses
reporting omega-3 supplementation in pediatric IST. Outcomes of interest were mean
24-hour heart rate, HRV indices, symptom improvement, and adverse events.
Results: A total of 267 records were identified; after removal of duplicates and
exclusions, 10 studies met inclusion criteria. Omega-3 supplementation was
associated with a mean reduction in 24-hour heart rate of 6–10 bpm and significant
improvements in HRV. Pediatric studies reported good tolerability, with mild
gastrointestinal symptoms as the most common adverse events. Conclusion: Omega
3 supplementation shows promise as a safe, adjunctive therapy for pediatric IST, with
consistent evidence for heart rate reduction and improved autonomic regulation.
However, current evidence is limited, and larger randomized trials are required to
confirm efficacy and define optimal dosing strategies.