The high morbidity and health care costs among patients with high risk cardiovascular disease along with the reduced immune responses to standard dose influenza vaccines in patients with heart failure provides a compelling rationale to investigate alternative influenza vaccination strategies in this group. INVESTED is an outcomes study in patients with recent acute myocardial infarction (AMI) or heart failure (HF) to test whether a four-fold higher dose of trivalent influenza vaccine will reduce morbidity and mortality compared to standard dose quadrivalent vaccine. INVESTED will test the hypothesize that high dose vaccine will reduce the composite of all cause death or cardiopulmonary hospitalizations in this population, with the following specific aims: