Atrial fibrillation ascertainment was based on self-report of atrial fibrillation, atrial flutter, or cardioversion in an interview with a trained nurse, ICD-9 codes of 427.3 or ICD-10 codes of I48.X in hospitalization records, or history of a percutaneous ablation or cardioversion based on OPCS-4 coded procedure (K57.1, K62.1, K62.2, K62.3, K 62.4) as performed previously.30
