The Silent Face of Atrial Fibrillation: A Systematic Review of Associated Factors, Clinical Phenotype, and Outcomes

Background: Asymptomatic atrial fibrillation (AF) is increasingly recognized through incidental diagnosis and continuous rhythm monitoring, yet its clinical phenotype and prognostic significance remain incompletely characterized. We systematically evaluated factors associated with asymptomatic AF and its clinical outcomes. Methods: This systematic review was conducted according to PRISMA 2020 recommendations. PubMed/MEDLINE, Scopus, and EMBASE were searched from inception through 1 September 2026. Studies reporting demographic, clinical, anthropometric, laboratory, electrocardiographic, imaging, or therapeutic correlates of asymptomatic AF and/or associated clinical outcomes were eligible. Given substantial clinical and methodological heterogeneity, evidence was synthesized using structured qualitative analyses and descriptive summaries of study-level data, without formal meta-analysis or inferential testing of aggregated between-group differences. Results: Twenty-three studies were included, comprising 47,456 patients with asymptomatic or subclinical AF and 126,894 participants in the corresponding comparator groups. Study-specific evidence identified male sex, lower ventricular rate, and long-standing persistent or permanent AF as relevant correlates of asymptomatic presentation. Greater left atrial remodeling, including larger atrial dimensions and impaired mechanical function, was also reported in selected studies of silent AF, whereas conventional left ventricular structure and systolic function showed relatively similar descriptive estimates across the available datasets. Selected studies identified metabolic biomarkers and thoracic morphology as additional potential correlates. Rhythm-control strategies and catheter ablation showed numerically lower utilization in descriptive summaries of asymptomatic AF, although the contributing populations were heterogeneous and not necessarily directly comparable. Prognostic findings were heterogeneous: mortality and thromboembolic outcomes were generally comparable between asymptomatic and symptomatic AF in several individual studies, whereas other investigations reported a greater burden of heart failure and heart failure-related events among symptomatic patients. Conclusions: Asymptomatic AF represents a heterogeneous clinical phenotype rather than a benign form of the arrhythmia. A lower ventricular response may attenuate symptom perception, while atrial remodeling and cardiovascular risk may progress despite the absence of symptoms. Symptom status should therefore not replace established cardiovascular risk assessment. Thoracic geometry may represent an additional determinant of symptom perception, although current evidence remains preliminary and requires prospective validation.