Observational studies implied that catheter ablation may be safe and effective for treating atrial fibrillation in both young and old people. It had not been studied in a big, randomized experiment. The report summarized CABANA trial results based on age at enrollment (Catheter Ablation versus Antiarrhythmic Drug Therapy for Atrial Fibrillation). Patients with atrial fibrillation who were ≥65 years old or older and had more than one risk factor for stroke were randomly allocated to catheter ablation or medication treatment. The main result was a combination of death, debilitating stroke, significant bleeding, or cardiac arrest. Secondary outcomes were all-cause death, the composite of mortality or cardiovascular hospitalization, and atrial fibrillation recurrence. Proportional hazards regression models were used to modify treatment effect estimates for baseline covariables. 

About 766 (34.8%) of the 2,204 patients randomly allocated in CABANA were <65 years old, 1,130 (51.3%) were 65 to 74 years old, and 308 (14.0%) were ≥75 years old. Catheter ablation was associated with a 43% reduction in the primary outcome for patients aged 65 to 74 years (aHR, 0.57 [95% CI, 0.30–1.09]), a 21% reduction for patients aged 65 to 74 years (aHR, 0.79 [95% CI, 0.54–1.16]), and an indeterminate effect for patients aged 75 years (aHR, 1.39 [95% CI, 0.75–2.58]). The four-year incident rates for ablation vs medication treatment were 3.2% versus 7.8%, 7.8% compared 9.6%, and 14.8% versus 9.0%, respectively. The primary outcome aHR rose (ie, became less favorable to ablation) by an average of 27% for every 10-year rise in age (interaction P value=0.215). A similar pattern was observed in all-cause mortality: for every 10-year rise in age, the aHR increased by 46% on average (interaction P value=0.111). Across all age categories, ablation was associated with reduced recurrence rates of atrial fibrillation than medication treatment (aHR 0.47, 0.58, and 0.49, respectively). Treatment-related problems were uncommon in both groups (3%), independent of age. Researchers discovered age-related differences in clinical outcomes for catheter ablation vs pharmacological treatment, with younger patients reaping the greatest relative and absolute advantages from catheter ablation. In the oldest patients, there were no prognostic improvements from ablation.