Supraventricular tachyarrhythmias in arrhythmogenic cardiomyopathy and Brugada syndrome: a systematic review

Background: Arrhythmogenic cardiomyopathy (ACM) and Brugada syndrome (BrS) are inherited arrhythmogenic disorders historically defined by their predisposition to ventricular arrhythmias and sudden cardiac death (SCD). Accumulating evidence indicates that both conditions also involve the atrial myocardium and are associated with a high prevalence of supraventricular tachyarrhythmias (SVT). A clearer understanding of their mechanisms and clinical impact is essential to optimize risk stratification and management. Methods: A systematic review was conducted in accordance with the PRISMA 2020 statement. PubMed and the Cochrane Library were searched up to December 2025 for studies reporting atrial fibrillation (AF), atrial flutter (AFL), atrioventricular nodal re-entrant tachycardia (AVNRT), or atrioventricular re-entrant tachycardia (AVRT) in patients with ACM or BrS. Of 487 records identified, 486 were screened after removal of one duplicate, and 30 studies met the inclusion criteria. Data on atrial substrate, SVT prevalence, mechanisms, and clinical outcomes were extracted. Results: SVT were consistently more frequent in both ACM and BrS than in age-matched general populations. AF was the most common arrhythmia, often arising at a young age and in structurally normal atria. Across studies, SVT were linked to inappropriate implantable cardioverter-defibrillator (ICD) shocks, heart failure progression, recurrence of ventricular arrhythmias, and an elevated thromboembolic risk that was frequently underestimated by the CHA₂DS₂-VASc score. Conclusions: SVT represent a clinically relevant manifestation of ACM and BrS and carry prognostic implications for arrhythmic monitoring, ICD programming, and thromboembolic risk assessment. Prospective studies are needed to refine risk-stratification tools and to clarify the mechanistic overlap between these inherited arrhythmogenic syndromes.