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Home > All Images > 1989 > June > 27 Jun 1989

Images Dated 27th June 1989

Choose from 16 pictures in our Images Dated 27th June 1989 collection for your Wall Art or Photo Gift. All professionally made for Quick Shipping.

Artificial heart valve Featured 27 Jun 1989 Image

Artificial heart valve

False-colour angiogram (X-ray image) of the human heart, showing a mechanical Starr-Edwards aortic heart valve. A normal aortic valve regulates the flow of blood from the left ventricle into the aorta, the body's main artery, for distribution around the circulation. The valve consists of three cusps, shaped like half-moons. Malfunctions of the valve include fusion of the cusps, often the result of the scarring that follows rheumatic fever. This results in a narrowing of the valve's opening (aortic stenosis) with a consequent reduction in blood flow. An incompetent aortic valve may also cause blood to reflux back into the left ventricle (aortic regurgitation)