PMC:99044 / 4072-4926 JSONTXT

{"project":"2_test","denotations":[{"id":"11897013-11927203-9155456","span":{"begin":298,"end":299},"obj":"11927203"}],"text":"Study cohorts\nAF cohort: We identified patients aged 40–89 years with a first ever recorded diagnosis of permanent/chronic atrial fibrillation in 1996. The diagnosis was confirmed by the general practitioners (GPs) through a questionnaire, this process is describe in detailed in a previous study [4]. We requested the GPs to confirm whether the episode of chronic AF was the first ever and to provide information on diagnostic tests, procedures and aetiology of the AF (patient confidentiality was always preserved). We excluded patients classified by the GP as having paroxysmal AF, 1,035 were finally confirmed. General Population cohort: Using the same source population in which the AF patients were identified and applying the same eligibility criteria as for the AF cohort, we sampled an age and sex matched cohort of 5,000 individuals free of AF."}