Coronary heart disease, also known as coronary artery disease (CAD), is caused by a build-up of plaque in the heart's arteries, clogging the vessels and limiting the supply of blood and oxygen to the heart muscle itself. This can ultimately lead to heart attack. CAD can begin as early as a person’s 30’s or 40’s and, without lifestyle changes, typically worsens over time. The most common symptom of CAD is chest pain, or angina. Often fatigue and shortness of breath may also occur. A physician can diagnose CAD by asking questions and performing a physical exam; however, imaging tests, such as a CT scan or angiography, and stress tests are often also necessary. Lifestyle changes are recommended to control CAD symptoms, but medication may be needed as well. Surgery may be required if the heart is badly damaged.