A Clinical Trial Screening for Atrial Fibrillation (AF-CATCH)

1. Study name:A randomized clinical trial on atrial fibrillation screening by using an automated electrocardiogram system in an elderly Chinese population 2. Rationale: Failure in the diagnosis and management of atrial fibrillation leads to high incidence of stroke and high mortality and disability. It is therefore imperative to diagnose and manage atrial fibrillation in a timely and effective fashion to prevent the complications of atrial fibrillation. 3. Objective:The primary objective is to investigate whether more frequent ECG recordings and analyses with this automated ECG system (4 times/year) would significantly improve the detection of atrial fibrillation compared to a single annual ECG screen.The secondary objective is to explore whether even more frequent ECG recordings and analyses (8 times/year) would further improve the detection of atrial fibrillation. 4. Study design: The present study is designed as a randomized controlled trial of parallel group (two). 5. Study population: Men and women aged at least 65 years (n=7000) meet the inclusion/exclusion criteria. 6. Randomization and treatment: Eligible subjects will be randomized in a 1:1 ratio into the usual and intensive screening groups with 3500 patients in each group, and within the intensive screening group in a 3:1 ratio into the intensive and more intensive subgroups with 2625 and 875 patients, respectively. 7. Follow up: 1)Usual screening group: ECG recordings at baseline plus at 1 and 2 year of follow-up; three ECG recordings in total. 2)Intensive screening subgroup: ECG recordings at baseline plus quarterly during follow-up, at months 3, 6, 9, 12, 15, 18, 21 and 24; 9 ECG recordings in total. 3)More intensive screening subgroup: ECG recordings at baseline plus weekly during the first month of follow-up and quarterly afterwards, at weeks 1, 2, 3 and 4 and months 3, 6, 9, 12, 15, 18, 21 and 24; 13 ECG recordings in total. 8. Sample size estimation: The number of required subject for the whole tri