Coronary artery disease (CAD) occurs when a substance called plaque builds up in the arteries that supply blood to the heart (called coronary arteries). Plaque is made up of cholesterol deposits, which can accumulate in your arteries. When this happens, your arteries can narrow over time. This process is called atherosclerosis.
Plaque buildup can cause angina, the most common symptom of CAD. This condition causes chest pain or discomfort because the heart muscle doesn't get enough blood. Over time, CAD can weaken the heart muscle. This may lead to heart failure, a serious condition where the heart can't pump blood the way that it should. An irregular heartbeat, or arrhythmia, can also develop.
For some people, the first sign of CAD is a heart attack. A heart attack occurs when plaque totally blocks an artery carrying blood to the heart. It also can happen if a plaque deposit breaks off and clots a coronary artery.