When deployed on smartphones, virtual agents have the potential to deliver life-saving advice regarding emergency medical conditions, as well as provide a convenient channel for health education to help improve the safety and efficacy of pharmacotherapy. This paper describes the use of a smartphonebased virtual agent that provides counseling to patients with Atrial Fibrillation, along with the results from a pilot acceptance study among patients with the condition. Atrial Fibrillation is a highly prevalent heart rhythm disorder and is known to significantly increase the risk of stroke, heart failure and death. In this study, a virtual agent is deployed in conjunction with a smartphone-based heart rhythm monitor that lets patients obtain real-time diagnostic information on the status of their atrial fibrillation and determine whether immediate action may be needed. The results of the study indicate that participants are satisfied with receiving information about Atrial Fibrillation via the virtual agent.