This study is a cluster randomized, stepped wedge clinical trial assessing implementation and effect of a locally-developed quality improvement toolkit for patients with acute coronary syndrome (ACS) in Kerala, India. Hospitals will be randomized after stratification for size to one of five cohorts. After a four-month baseline period, the quality improvement toolkit will be implemented in all hospitals in cohort 1. Through a one-way crossover design, these hospitals will continue to use the quality improvement toolkit through the end of the trial for all acute coronary syndrome (ACS) patients. Cohorts 2 through 5 will implement the quality improvement toolkit at time points 8, 12, 16, and 20 months respectively, continuing the use of the toolkits from that time forward to the end of the study. The primary outcome is 30-day MACE rates, including death, reinfarction stroke, or major bleeding. Rates will be continuously collected and compared at one interim time point for safety and efficacy. Final analysis compares MACE rates before and after implementation of the quality improvement toolkits, accounting for cluster effects of hospital, cohort and time.