Overall, the investigators aim to recruit 150 subjects during their hospitalization for an acute coronary syndrome (ACS). At two weeks post-ACS, the investigators will assess levels of gratitude and optimism, draw blood for baseline levels of biomarkers, gather baseline information about health behaviors critical to cardiac health, and obtain baseline measures of symptoms and function. Finally, the investigators will repeat assessments of biomarkers, behavior, and function at 6 months to allow us to assess the impact of gratitude and optimism on these outcomes; the investigators will also have an objective measure of physical activity via accelerometer (step counter) at 6 months.