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The randomized controlled trial will investigate whether more frequent electrocardiographic (ECG) recordings and analyses with an automated ECG system would improve detection of atrial fibrillation compared to a single annual ECG screen in elderly Chinese in the community health center.
Men and women (≥65 years) will be randomized into intensive (n=3500) and usual screening groups (n=3500), and within the intensive screening group into intensive (n=2625) and more intensive subgroups (n=875). ECG recordings will be performed with an automated ECG analysis system AliveCor® Heart Monitor at 1 year in the usual screening group, at 3, 6, 9 and 12 months in the intensive screening subgroup, and at 1, 2, 3 and 4 weeks and 3, 6, 9 and 12 months in the more intensive screening subgroup. The primary outcome is the detection rate of atrial fibrillation between the usual and intensive screening groups. Sample size estimation was based on a projected detection rate of atrial fibrillation of 2.0% by a single ECG recording at 12 months, an improvement of 50% with more frequent ECG recordings, a=0.05, power=80% and one-sided test.
The outcome measure is the detection rate of atrial fibrillation in the usual and intensive screening groups. The primary comparison is between the usual and intensive screening groups. The hypothesis is that the detection rate of atrial fibrillation would be 50% higher in the intensive than usual screening groups. An exploratory comparison is between the intensive (ECG recordings quarterly) and more intensive (quarterly plus weekly in the first month after randomization) screening subgroups within the intensive group.
The trial will provide evidence on the clinical effectiveness of more frequent ECG recordings by a handheld automated analysis system in the detection of atrial fibrillation. If proved effective, intensive screening by more frequent ECG recordings might have to be considered in people at high risk of atrial fibrillation. If not, for instance, for inadequate power of the trial, an extended follow-up with an even more intensive screening approach may be considered to increase the detection rate of atrial fibrillation.