Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Happitech. Provided the mobile photoplethysmography application Background Undiagnosed atrial fibrillation (AF) poses a great risk for stroke in high-risk patients. Different screening strategies have been developed to identify these patients. Geriatric patients often have multimorbidity, and are to be considered a population at very high risk for development of AF and cardiovascular events, but may have less access to wearable screening devices. Purpose The Dutch multicentre study into opportunistically screening of Geriatric patients for Atrial Fibrillation using a PPG smartphone App (the Dutch-GERAF Study) applies opportunistic screening to ambulatory geriatric patients, to identify new cases of AF and optimize stroke prevention. This preliminary analysis describes the feasibility and willingness to use of a smart phone photoplethysmography (PPG) application in an ambulatory cohort. Method Analysis of participation data and PPG use, of all included patients aged 70 years or older within the GERAF study. The GERAF study is a multicentre study on opportunistic screening for AF using a PPG application among patients visiting a geriatric outpatient clinic. All patients without a pacemaker/ICD, severe tremor, or severe dementia were invited to participate, during a 6 months screening period. Patients were stimulated to use the application at home on their own mobile device at least 3 times within 6 months following inclusion. If preferred by the patient, the application was installed on the mobile device of a spouse or other family member. The PPG signals were analysed using the commercially available algorithm. Results Data on PPG use for patients was available for 568 patients. Of these, 122 (21.5%) had a history of AF, and therefore not included in this analysis. Data on PPG use was analysed of 446 patients, 240 were female (54%), average age was 79 ± 5.5 years, the oldest patient was 95 years old. In total, ...