Atrial fibrillation (AF) is a major treatable risk factor for stroke, but it may be hard to detect because it is frequently silent and intermittent. New ambulatory cardiac monitoring technologies have the potential to improve early detection of AF. This trial investigates AF screening in primary care patients using the ZIO XT Patch, a wearable adhesive patch monitor that provides continuous ECG recording for up to 14 days, in addition to the WatchBP home blood pressure monitor that has built-in AF screening capability.

SCREEN-AF is an investigator-initiated, multicenter, open-label, two-group randomized controlled trial investigating non-invasive, home-based AF screening. The trial targets patients aged 75 years or older with a history of hypertension and without known AF who would be potential anticoagulant candidates if AF were detected. Eligible participants will be recruited from primary care practices and randomly allocated (1:1) to one of two groups:

• The control group will receive standard care for 6 months (including a pulse check and heart auscultation by a physician at baseline and 6 months).
• The intervention group will undergo ambulatory screening for AF with a 2-week continuous ECG patch monitor worn at baseline and again at 3 months, in addition to standard care for 6 months (including a pulse check and heart auscultation by a physician at baseline and 6 months). The intervention group will also receive a home BP monitor with automatic AF detection capability to be used twice daily for 2 weeks during the ECG monitoring blocks.

The hypothesis is that continuous ambulatory cardiac rhythm monitoring using an adhesive ECG patch monitor will be superior to standard care for AF detection. The overall aim of this research is to establish a practical and cost-effective screening strategy that could be applied in primary care for early detection of AF in patients who would benefit from anticoagulant therapy if AF were detected. The ultimate goal of this primary prevention initiative is to prevent more strokes, and stroke-related deaths, disability, dementia, hospitalizations and institutionalization, through the early detection and treatment of AF.

Inclusion Criteria:

1. Age ≥75 years without known atrial fibrillation or atrial flutter.
2. The participant is clinically in sinus rhythm (both heart auscultation and 30- second pulse palpation have been performed by the enrolling physician and neither detects an irregular rhythm suggestive of atrial fibrillation).
3. History of hypertension requiring antihypertensive medication.
4. Written informed consent from the participant.

Exclusion Criteria:

1. Any previously documented atrial fibrillation or atrial flutter ≥30 seconds.
2. Implanted pacemaker, cardiac defibrillator, cardiac loop recorder, or deep brain stimulator.
3. Likely to be poorly compliant or unreliable using home screening devices or with study follow-up requirements because of cognitive or other issues, or life expectancy <6 months due to concomitant disease.
4. Has a condition which in the opinion of the enrolling physician would not permit chronic treatment with oral anticoagulant therapy.
5. Patient already taking long-term oral anticoagulant therapy.
6. Known allergic reaction/intolerance to skin adhesives.