Your doctor will perform a physical examination and ask about your personal and family medical history. The tests needed to diagnose heart disease depend on the disease your doctor thinks you may have. In addition to blood tests and chest X-rays, tests to diagnose heart disease also include. According to the Centers for Disease Control and Prevention (CDC), heart disease is the leading cause of death in the United States. In the United States, about a quarter of deaths are caused by heart disease, which affects all genders and all races and ethnicities.If you are diagnosed with coronary heart disease, simple lifestyle changes can reduce the risk of recurrence. For example, quitting smoking after a heart attack will quickly reduce your future heart attack risk to a level close to that of a non-smoker.