The American Heart Association launched Mission: Lifeline (M:L) in 2007 with a goal of reducing system barriers to prompt treatment for heart attacks, beginning with the 911 call and continuing through hospital treatment. M:L also encourages regional collaboration and measurement of heart attack systems of care. Regional reports allow hospitals to see blinded comparisons to other hospitals in their region as well as regional, state and national benchmarks. We compared two major metropolitan areas.Data analysis and measurement using Mission: Lifeline (M:L) regional reports created from data in the ACTION Registry-Get With The Guidelines (ARG) national registry, was initiated in Chicago and St. Louis. Measures impacting systems of care, operations and outcomes were shared with hospitals and EMS. Regional reports include de-identified hospital data and state and national benchmarks.Data was shared at regional meetings and opportunities for performance improvement were identified. We reviewed First Medical Contact (FMC) to Percutaneous Coronary Intervention (PCI)and other system measures quarterly from 2010-2015. In order to facilitate regional improvement, system level M:L reports are generated quarterly. This allows hospitals to see blinded comparisons to other hospitals in their region as well as regional, state and national benchmarks.The FMC to PCI and other system measures were examined as indicators of process improvement in Chicago and St. Louis to determine if data sharing activities would impact systems improvement. One obstacle was getting hospitals to meet the data entry deadlines so their data was included in the regional reports. American Heart Association (AHA) staff worked with hospitals to help facilitate this.Data sharing in two EMS major metropolitan regions encouraged collaboration and performance improvement impacting FMC to PCI times and other measures. We saw a marked decrease in FMC to PCI in the first 6 quarters while regions were meeting regularly and initiating PI efforts. When state initiatives in Missouri took priority and the region was not actively meeting, we saw a rise in this measure.