Age-Related Differences in the Clinical Profile and Management of Atrial Fibrillation: Results from the Multicentre REGUEIFA Registry

<b>Background/Objectives:</b> Atrial fibrillation (AF) is the most common sustained arrhythmia in adults, with a prevalence that increases with age. In older patients, its clinical impact is particularly relevant due to higher mortality and greater comorbidity burden. This study aimed to compare patients aged ≥80 years with younger patients in a large AF cohort. <b>Methods:</b> The REGUEIFA registry is an observational, prospective, multicentre study including consecutive patients with AF managed by cardiologists. Baseline clinical characteristics, comorbidities, complementary test findings, AF type, therapeutic strategies, anticoagulation patterns, and patient-reported outcomes were compared. <b>Results:</b> A total of 1007 patients were included, of whom 18.2% were aged ≥80 years. Older patients showed a higher prevalence of hypertension, renal dysfunction, conduction disorders, chronic obstructive pulmonary disease, and neoplastic disease, along with higher thromboembolic (CHA₂DS₂-VASc 3.7 ± 1.04 vs. 2.1 ± 1.49; <i>p</i> < 0.001) and haemorrhagic risk (HAS-BLED 1.3 ± 0.8 vs. 0.6 ± 0.7; <i>p</i> < 0.001). Permanent AF was more frequent, whereas rhythm control strategies and antiarrhythmic drug use were less common, and quality of life was poorer. Anticoagulation rates were high in both groups (≈90%), with greater use of vitamin K antagonists (VKAs) in older patients, although anticoagulation control was similar. Patients treated with direct-acting oral anticoagulants reported a lower treatment burden and greater perceived benefit than those receiving VKAs. <b>Conclusions:</b> Patients aged ≥80 years with AF exhibit greater comorbidity, poorer perceived health status, and higher thromboembolic and haemorrhagic risk. Their management is more often oriented towards rate control strategies and VKA use, while rhythm control approaches are more common in younger patients.