The American College of Cardiology and the American Heart Association guidelines are the nationally accepted standards for the treatment of patients with acute coronary syndromes. Despite this recognition, adherence to guideline recommendations remains suboptimal with 25% of opportunities to provide guideline appropriate care missed. To address performance gaps related to acute coronary syndrome care and improve patient outcomes, a performance improvement (PI) initiative was designed for cardiologists and emergency department physicians. As an American Medical Association-approved, standardized continuing medical education initiative, participating physicians can earn up to 20 American Medical Association-PRA Category 1 Credits by completing 2 phases of self-assessment in addition to developing and implementing a PI plan to address self-identified areas where improvement in patient care is needed. As the second in a series of 3 articles, this article describes the initial data submitted by 101 participating physicians and how their treatment practices compared with American College of Cardiology/American Heart Association guidelines as well as with current national standards. Overall, participating physicians meet guideline expectations with performance and documentation of a 12-lead electrocardiography, measurement of cardiac biomarkers, and administration of aspirin. Identified areas of improvement were the standardization of treatment protocols, use of risk assessment scores, appropriate dosing of anticoagulants, and improvement in patient treatment times. A noted challenge of this PI initiative is the low rate of physician participation, with fewer than 10% of registered physicians actively submitting patient data. This fact may reflect several barriers to PI, such as: (1) lack of time to collect and submit data, (2) the belief that current practices do not need to be improved, and (3) the need for system-based improvements.