2. Retrospective data collection Two clinical research nurses will perform retrospective chart review using a computerized data collection instrument. The following variables will be recorded: baseline patient characteristics, clinical variables, comorbid conditions, laboratory variables, procedural interventions (cardiac catheterization, PCI [not primary], and coronary artery bypass grafting) at any time during index hospitalization, medications (on admission, during the first 24 hours, and at discharge). Index hospitalization includes both admitting and transfer hospital stays.