319 Appropriate Duration of Extended Cardiac Monitoring for Atrial Fibrillation in Cryptogenic Stroke

Background Strokes due to cardio embolism are generally more severe and prone to early and long term recurrence. All forms of anticoagulant therapy are associated with a two thirds risk reduction in acute ischaemic stroke associated with atrial fibrillation. Establishing a diagnosis of paroxysmal atrial fibrillation can be a challenging one. Our study will attempt to answer the question as to what duration of extended cardiac monitoring is required when screening for atrial fibrillation in cryptogenic stroke. Methods We examined the time of atrial fibrillation initial diagnosis in 50 patients with an original working diagnosis of cryptogenic stroke but later have atrial fibrillation confirmed on extended monitoring. All patients wore the external loop recorder from 1 day to 3 weeks’ duration. On return of the device, data from the external loop recorder was downloaded, and reviewed by a consultant cardiologist. The total duration of monitoring using the external loop recorder was recorded. The time to first episode of algorithm detected atrial fibrillation was recorded. Results The mean duration of extended cardiac monitoring using the external loop recorder was 120.1days By seven days, atrial fibrillation had been detected in 94% of patients. By 72 hours, atrial fibrillation had been detected in 78% of patients. The mean age of participants was 58.3 years. 54.4% were female. The mean time to detection of atrial fibrillation was 52.9 hours. The median time to detection of atrial fibrillation was 34.2 hours. Conclusion External loop recorders present an opportunity for detection of paroxysmal atrial fibrillation in high risk individuals. Our study shows the feasibility and accuracy of a screening duration of seven days in the high risk post ischaemic stroke population. A one week screening timeframe allows us to screen twice as many patients for paroxysmal atrial fibrillation. Successful screening for atrial fibrillation in this high risk group allows the commencement of acceptable and safe anticoagulant therapy.