If an artery narrows too much, you can feel chest pain. A heart attack occurs if an artery closes all the way or narrows so much that a blood clot blocks the blood flow.

Some risk factors for heart disease are beyond your control, but others, such as smoking or high blood pressure, you can do something about.

Your heart is a pumping muscle that works nonstop to keep your body supplied with oxygen-rich blood. Signals from the heart’s electrical system set the speed and pattern of the pump’s rhythm. Valves keep the blood moving in one direction, through the heart’s four chambers.