Abstract

Background The prevalence of left atrial flutter (LAFL) is increasing, primarily due to the growing number of individuals undergoing cardiac ablation for atrial fibrillation (AF). However, patients develop LAFL without prior cardiac intervention - a condition also termed de novo LAFL. The extent to which aetiology influences the characteristics and outcomes of LAFL remains unclear. Purpose This systematic review aims to synthesise and compare existing literature on the characteristics and ablation outcomes of LAFL occurring de novo and in patients with a history of percutaneous AF ablation. Our findings will offer valuable insights for clinical practice and guide future research directions. Methods We conducted a systematic review of the PubMed and Ovid databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included studies of LAFL ablation in adults, regardless of publication year. Eligible studies focused on either de novo individuals, without prior cardiac intervention such as surgery or ablation, or patients with a history of percutaneous cardiac ablation for AF. Studies were excluded if ablation outcomes could not be distinguished between these groups (e.g., if both de novo and post-AF ablation LAFL were analysed together without separate outcome data). Data extracted included demographics, surface electrocardiograms, electrophysiological mechanisms, procedural success rates, recurrence rates, and complications. Statistical analysis was conducted in R, using chi-squared and t-tests. Results 38 studies were included: 14 focusing on de novo LAFL (n=223) and 24 on LAFL following prior percutaneous AF ablation (n=1,454). Patients in the de novo group were older (67.3 vs. 64.2 years, p=0.03), had lower rates of hypertension (43.8% vs. 58.9%, p<0.01) and diabetes (9.6% vs. 20.5%, p=0.02), but a higher prevalence of structural heart disease (46.2% vs. 32.0%, p<0.01). They were also less likely to present with concurrent AF (17.4% vs. 61.3%, p<0.01). Mitral flutter was the most common subtype in both groups but represented a significantly greater proportion in the previous percutaneous AF ablation group (31.2 vs. 73.8%, p=<0.01). Acute ablation success was significantly higher in the de novo group (95.1% vs. 87.1%, p<0.01). A larger proportion of de novo LAFL patients underwent a second ablation procedure, though acute success was comparable and lower than those of the initial ablation for LAFL. Conclusion Ablation for LAFL is generally safe and effective in both de novo cases and those with a history of percutaneous AF ablation. While circuit characteristics differ and acute success rates are higher in de novo LAFL, recurrence remains common and comparable in both populations. Further research is needed to better understand the pathophysiology, optimise treatment strategies, and refine management approaches to improve patient outcomes.