The presence of atrial fibrillation increases the risk of stroke, although the short-lasting and asymptomatic nature of the condition means that if often goes undetected.
Atrial fibrillation (AF) is one of the most common and treatable causes of strokes and it has been estimated that between 10 and 20% of ischaemic strokes are due to undiagnosed AF. However, once detected and treated with anticoagulants, up to two-thirds of strokes can be prevented. Given the importance of both detection and effective management of AF, much interest has been focused on the need to screen patients for undiagnosed disease. Nevertheless, while secondary preventative screening, i.e., among those who have already had a stroke, can help identify AF, there is a lack of data to determine which factors increase the risk of AF and therefore the patient cohort who merit screening. Technological advances have enabled screening through the use of a wearable device that provides continuous ECG (cECG) monitoring. Using a cECG patch device, a multi-centred, Canadian and German team, the SCREEN-AF group, conducted a randomised clinical trial of AF screening among older, community-dwelling patients but without known AF, compared to standard care. For the purposes of the study, standard care comprised baseline pulse checks and heart auscultation by a physician and after 6 months. Included patients were older than 75 years, with a CHADS 2 score greater than 2, which indicates a moderate or high risk of stroke. The screening group received an ambulatory cECG patch monitor that was worn at all times for 2-weeks, at baseline and after 3 months in addition to standard care. As well as the use of a wearable, the screening group also received an automated home blood pressure monitor which included an AF screening algorithm which was designed to be use twice daily during the cECG monitoring period. The primary outcome for the study was detection of AF within six months of randomisation either via the cECG or through usual care.
A total of 856 individuals were randomised to either screening (434) or standard care (422). Both groups were matched and the mean age of the screening group was 79.8 years (58.8% female). The primary outcome occurred in 5.3% of those assigned to screening compared to 0.5% of the receiving standard care (relative risk, RR = 11.2, 95% CI 2.7 – 47.1, p = 0.001), resulting in a number-needed to screen of 21. Furthermore, the majority (87%) of AF cases were detected using the cECG monitors. The median AF duration on cECG was 6.3 hours and anticoagulant therapy was subsequently prescribed to 75% of those with screen-detected AF. The monitors were well tolerated and only 5 patients experienced an adverse skin reaction. Concluding, the authors noted that the wearable device was an effective means for detection of AF in older patients.
Gladstone DJ et al. Screening for Atrial Fibrillation in the Older Population. A Randomized Clinical Trial. JAMA Cardiol 2021