How Your Heart Works

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Your heart is a muscle about the size of your fist. It is made up of four chambers: the right atrium, right ventricle, left atrium and left ventricle.


The right side of the heart receives blood that is low in oxygen from veins all over the body. It pumps this blood into the lungs where it becomes re-oxygenated. The left side of the heart receives this oxygen-rich blood from the lungs. It pumps the blood back out to the rest of the body.

While blood is circulating through the body, it delivers oxygen and nutrients to tissue through the capillaries and, at the same time, picks up carbon dioxide and other waste materials. The veins return the deoxygenated blood to the heart and the cycle begins again.

Why Arrhythmia Occurs

The heart's pumping action is driven by electrical stimulation within the heart muscle. The heart's electrical system allows it to beat in an organized pattern. Electrical signals in your heart can become blocked or irregular, causing a disruption in your heart's normal rhythm. When the heart rhythm is too fast, too slow, or out of order, arrhythmia—also called a rhythm disorder—occurs. When your heart beats out of rhythm, it may not deliver enough blood to your body.

Animations

    Recommended animations:
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  • Understanding Arrhythmias: Arrhythmia Explained

View Understanding Arrhythmias and Treatment Options Animations