INTRODUCTION
The PRE-DETERMINE Biologic Markers and Sudden Cardiac Death Study is an observational study coordinated by Brigham and Women's Hospital and funded by the National Heart, Lung, and Blood Institute (NHLBI). Approximately 6,000 male and female participants over the age of 18 years old with a prior history of coronary artery disease (CAD) that may have resulted in a heart attack (narrowing or complete blockage of a coronary artery that results in death of the heart muscle supplied by that vessel) and/or mild to moderate weakness of the heart muscle have been enrolled at 100 clinical sites that specialize in cardiology or electrophysiology throughout the United States and Canada for the purpose of following these individuals for long-term outcomes. Participants are contacted every 6-months and asked to complete a questionnaire via mail for the purpose of studying long-term outcomes.