Atrial fibrillation (AF) is a large and growing healthcare problem worldwide. Over 7 million people in the U.S. and Europe currently suffer from atrial fibrillation, and this number is expected to double before 2050. The lifetime risk of AF is high: ~24% at age 40, and this risk remains fairly constant at older ages, with 22% lifetime risk at age 80 [1]. AF significantly increases the risk of stroke and mortality, and can greatly limit quality of life. Little research has been done on AF and ischemic cardiomyopathy, though it is a relatively common co-morbidity. CT found increased prevalence (41% vs 27%) of coronary artery disease (CAD) in patients with AF compared to patients with similar pre-test risk but no AF [2]. AF patients with a positive SPECT scan for CAD have a worse prognosis for cardiac events than patients with positive SPECT but without AF [3]. It was recently reported that in a study of 253 AF patients, that AF patients with positive SPECT studies had a very high number of false positives - only 15% of patients had significant CAD by angiography (compared to 67% in the control group) [4, 5]. Just over half of the patients were in sinus rhythm at SPECT, but since similar numbers of positives were seen in each half, the authors did not feel that imaging during AF was the cause of the poor specificity.