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