The Microlife(®) 'WatchBP Home A' oscillometric blood pressure monitor detects irregular pulse, suggestive of atrial fibrillation (AF). Early detection of AF can prevent thromboembolic stroke via anticoagulation therapy. The device was considered by the Medical Technologies Evaluation Programme of the UK National Institute for Health and Care Excellence (NICE). The sponsor (Microlife) identified 10 studies. These were reviewed by an External Assessment Centre (EAC) which considered three relevant to the decision problem, including one which found the device detected AF more accurately (sensitivity 96.8%, specificity 88.8%) than pulse palpation (87.2, 81.3%). The EAC concluded the technology had potential to improve detection of AF, but the three studies had uncertain external validity. From a cost-consequence model with a 1-year timeframe, the sponsor calculated the device would reduce electrocardiogram (ECG) referrals and prevent strokes, but incur anticoagulation therapy costs, with net NHS savings of £11.6 million and prevention of 221 strokes, annually. The EAC criticised the model for its limited time horizon, and its consideration of symptomatic AF patients who were outside the scope issued by NICE. The EAC applied a de novo Markov model, with a 10-year timeframe. The per use saving was calculated as £2.98 for asymptomatic patients aged 65-74 years and £4.26 for those aged 75-84 years, with the prevention of 53-117 nonfatal and 28-65 fatal strokes per 100,000 people screened. Following consideration by the NICE Medical Technologies Advisory Committee, NICE judged that the case for adoption was supported by the evidence (Medical Technologies Guidance 13; MTG13).