A mail-based atrial fibrillation (AF) screening programme with electrocardiogram (ECG) patch monitoring led to a modest long-term increase in AF diagnosis and anticoagulation exposure in older patients at moderate-to-high stroke risk within a late-breaking trial presented at the European Society of Cardiology (ESC) congress (29 August–1 September, Madrid, Spain), and simultaneously published in the Journal of the American Medical Association.
Explaining the AMALFI trial’s rationale, chief investigator Louise Bowman (Oxford Population Health, Oxford, UK) said: “AF is associated with an increased risk of stroke, but AF can be difficult to detect as it often occurs without symptoms and/or infrequently. Screening for AF has been proposed as a way to prevent strokes, but many short or infrequent asymptomatic AF episodes may be missed. The advent of new monitoring technology has enabled longer-duration screening. The AMALFI trial was designed to assess the long-term efficacy of remote screening for asymptomatic AF in older individuals at increased risk of stroke using a 14-day continuous ECG monitoring patch.”
In the investigator-initiated, parallel-arm unblinded randomised controlled AMALFI trial, eligible individuals were identified from 27 primary care practices in the UK via automated electronic health record searches. Participants were aged ≥65 years with a CHA2DS2VASc stroke risk score ≥3 for men or ≥4 for women. The key exclusion criterion was a previous diagnosis of AF or atrial flutter.
Participants were randomised 1:1 either to receive and return by postal mail an ECG patch monitor, or to usual care (control). The primary outcome was the proportion of participants with the presence of AF in primary care records within 2.5 years after randomisation, which was analysed using an intention-to-treat approach. A total of 5,040 individuals were randomised. At baseline, participants had a mean age of 78 years, 47% were female and 19% had a prior stroke or transient ischaemic attack.
There was a modest increase in AF diagnosis at 2.5 years with the ECG patch. A post-randomisation primary care record of AF was present in 6.8% of individuals in the intervention arm and 5.4% in the control arm (ratio of proportions, 1.26; 95% confidence interval [CI], 1.02–1.57; p=0.03). Patch-detected AF burden was bimodally distributed, with 33% of cases having 100% burden—meaning the entire monitoring period was spent in AF—while 55% had an AF burden of <10%.
At 2.5 years, mean exposure to oral anticoagulation was 1.63 months in the intervention arm and 1.14 months in the control arm (difference, 0.5 months; 95% CI, 0.24–0.75; p<0.0001). Stroke occurred in 2.7% of participants in the intervention arm and 2.5% in the control arm (event rate ratio, 1.08; 95% CI, 0.76–1.53).
“Our trial shows that remote AF screening with an ECG patch monitor in older patients at moderate-to-high stroke risk leads to a modest increase in AF diagnosis and anticoagulation exposure,” concluded AMALFI investigator Rohan Wijesurendra (Oxford Population Health, Oxford, UK). “However, AF diagnosis unrelated to the patch occurred more commonly than anticipated and over half of the patch-detected AF burden was low burden [below 10%]. This suggests that AF screening in this setting may have limited impact on stroke events; longer-term and cost-effectiveness analyses of AMALFI are planned, and will provide more insight in due course.”
