Heart disease. Coronary heart disease, sometimes called coronary artery disease or ischemic heart disease, is the most common type of heart disease. It refers to heart problems caused by narrowed coronary arteries that supply blood to the heart muscle. For some people, the first sign of coronary heart disease is a heart attack. Heart attack. A heart attack, or myocardial infarction, occurs when something, usually a blood clot, cuts off the flow of blood to the heart. Without oxygen and nutrients, the heart muscle begins to die. A heart attack may not be fatal, especially if you receive immediate medical attention and treatment, but it can still cause lasting damage to the heart. Stroke A stroke occurs when the blood supply to the brain is interrupted, causing the brain to lose its vital supply of oxygen and nutrients. A stroke can either be caused by a blood clot in the brain artery or when a blood vessel in the brain bursts and bleeds, damaging the brain tissue.