What does the heart muscle need in order to function?

The heart muscle needs a continuous supply of oxygen and nutrients in order to function properly. This is delivered to the heart muscle by the coronary arteries, which branch off from the aorta, the main artery that carries blood from the heart to the rest of the body. The coronary arteries supply oxygen-rich blood to the heart muscle, and the veins that drain the heart muscle carry away deoxygenated blood and waste products.