The earth's climate is changing, and significant sections of the globe are experiencing rising ambient heat levels. Anthropogenic greenhouse gas emissions are a major contributor to this change. Climate change has a number of negative health consequences, including cardiac health. Persons with pre-existing medical disorders, such as cardiac disease (including heart failure), people who work physically demanding jobs, and the elderly, are especially vulnerable. This study assesses the evidence basis for the heart health effects of changing climate conditions, with a focus on increased heat exposure, as well as the potential for further repercussions.