The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is a cost effective solution for early identification of atrial fibrillation (AF) in the form of a mobile app to reduce preventable strokes and associated costs. AF causes a third of all strokes, but often goes undetected due to the lack of symptoms. Two out of three AF-related strokes can be prevented through medication if a diagnosis is available. Given the ubiquity and accessibility of smartphones, the proposed mobile app can be distributed to large populations for large community screening of AF in a rapid and cost-effective manner unmatched by any existing solution. If successful, this will improve the quality of life for patients with AF by allowing the timely introduction of therapies to protect patients from stroke, and also prevent progression of AF from an easily treated condition to a refractory problem. <br/><br/>The proposed project will develop a mobile app capable of detecting AF using smartphones. There is a need for a highly accessible solution for screening of AF. The mobile app will use a smartphone camera to measure a user?s heart rhythm and apply a novel algorithm to identify the presence of AF. It is intended to provide people at high risk of developing AF with an easy and convenient tool for self-monitoring. This is transformative because instead of relying on the arrhythmia being present at the time of an in-clinic electrocardiogram to identify AF, this product will allow regular testing and can be operated by patients at home. In Phase I, a prototype will be developed and validated using real world data.