Pharmacological rhythm control strategy and outcomes in the oldest atrial fibrillation patients: an analysis of the nationwide Italian START registry

Background: Evidence on antiarrhythmic drugs (AADs) in the oldest atrial fibrillation (AF) patients is limited. We investigated clinical characteristics and outcomes associated with AADs use in this population. Methods: The oldest (age ≥ 80 years) AF patients from the nationwide START registry were included. Patients were divided into three groups: no AADs (n = 3573), class 1c-AADs (n = 207) and Amiodarone (n = 464). Factors associated with AADs were evaluated using multivariable logistic regression models. The associations between AADs and all-cause mortality were assessed using Cox proportional hazards models and cardiovascular events (CVEs) were analysed using Fine-Gray competing risk models. Results: Among 4244 patients (54.9% women), the mean age was 84.8 ± 3.8 years. AADs were prescribed in 671 patients (15.8%), including amiodarone in 464 (10.9%) and 1c-AADs in 207 (4.9%). 1c-AADs use was associated with younger age and fewer comorbidities, including lower prevalence of diabetes, heart failure, chronic obstructive pulmonary disease/obstructive sleep apnoea and better functional and social status. Amiodarone use was associated with coronary artery disease and markers of frailty. Over a median follow-up of 502 (interquartile range 362-857) days, 492 deaths and 548 CVEs occurred. In unadjusted analyses, 1c-AADs were associated with lower all-cause mortality and CVEs; however, these associations were no longer significant after multivariable adjustment. Amiodarone use was not associated with clinical outcomes in either unadjusted or adjusted analyses. Conclusion: In the oldest AF patients, AADs use is influenced by comorbidity burden and frailty-related characteristics. AADs were not independently associated with mortality or CVEs, suggesting that pharmacological rhythm control may be reserved for selected cases in this population.