This observational study will investigate the ability of AI-700 contrast ECHO to predict risk of future cardiovascular events occurring in patients who had a recent history of chest pain at the time of ECHO evaluation. Eligible patients were enrolled in either AI-700-32 or AI-700-33, which are completed Phase 3 international, multicenter, open-label, dual-injection studies of the myocardial imaging capabilities and safety of AI-700 administered intravenously in patients with chest pain. In the course of these Phase 3 studies, patients were evaluated with AI-700 contrast ECHO. In addition, eligible patients were to have had an evaluable pharmacologic stress-induced AI-700 ECHO assessment as part of AI-700-32 or AI-700-33.