Circulating lipid profiles and atrial fibrillation: from incident risk to post-ablation recurrence

Circulating lipids are widely used in cardiovascular risk assessment, but their relationship with atrial fibrillation (AF) differs from the conventional atherosclerotic framework. Higher triglyceride levels have often been associated with increased AF risk, whereas lower total cholesterol, low-density lipoprotein cholesterol, or remnant cholesterol have paradoxically been linked to greater risk in some populations. These inconsistent findings suggest that lipid measures may reflect stage-specific metabolic and clinical phenotypes rather than uniform causal exposures. This narrative review compares lipid-related evidence across two clinically distinct outcomes: incident AF and recurrence after catheter ablation. We examine conventional lipid measures, apolipoproteins, lipoprotein(a), and composite or longitudinal indices related to insulin resistance and metabolic burden. For incident AF, cholesterol-related markers show inverse, nonlinear, and population-dependent associations, while Mendelian randomization studies have not consistently supported direct causal effects. Post-ablation recurrence represents a treatment-response outcome occurring in patients with an established arrhythmogenic substrate and may be influenced by pre-existing atrial remodeling, lesion formation, postprocedural inflammation and repair, and residual triggers. In this setting, several composite or longitudinal indices integrating glycemia, adiposity, inflammation, or temporal variation have shown more consistent associations than individual conventional lipid measures in some cohorts. However, the evidence remains predominantly observational and is limited by heterogeneity in study populations, ablation modalities, recurrence definitions, rhythm-monitoring strategies, covariate adjustment, and treatment background. Studies of lipid-lowering and cardiometabolic therapies further indicate that changes in lipid concentrations do not necessarily produce parallel changes in AF risk or post-ablation rhythm outcomes. Accordingly, circulating lipids and their derived indices may be better interpreted as stage-specific markers of systemic metabolic burden, inflammatory status, comorbidity, and atrial substrate rather than as isolated causal factors or direct therapeutic targets. Future studies should prioritize longitudinal assessment, standardized outcome surveillance, external validation of incremental predictive value, and evaluation of treatment response before these measures can be incorporated into AF risk stratification or post-ablation management.