The Long-term Effect of Goal Directed Weight Management in an Atrial Fibrillation Cohort: A Long-term Follow-up Study (LEGACY) demonstrated that weight reduction in a cohort of Australian patients with atrial fibrillation (AF) resulted in a reduction in AF burden and improvement in AF symptom severity. The applicability of LEGACY in US cardiovascular practice is not known. A cohort of patients with AF from the National Cardiovascular Data Registry Practice Innovation and Clinical Excellence (PINNACLE) registry of US cardiovascular ambulatory care practices was created. The proportion of PINNACLE AF patients meeting enrollment criteria for LEGACY was assessed. Differences between these patients and LEGACY trial patients were qualitatively compared. Treatment for AF among LEGACY eligible and noneligible patients was compared. Among 349,999 US patients with AF from 179 cardiovascular practices in the PINNACLE registry, 197,255 (56.4%) met enrollment criteria for LEGACY. LEGACY-eligible PINNACLE AF had significantly lower rates of tobacco and alcohol abuse than the LEGACY trial population. There were significant differences in drug therapy comparing LEGACY eligible and LEGACY noneligible PINNACLE AF patients. In this cohort of patients in ambulatory practice in the United States with AF, over 1/2 were potential candidates for a weight management program. Differences between patients in practice and those enrolled in the trial could influence the success and impact of the LEGACY weight management intervention. Our study identifies a potential opportunity to improve AF morbidity and costs to the health care system in the United States by implementing a structured weight reduction program, such as that described in LEGACY.