How aortic valve stenosis affects the heart's blood supply

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How aortic valve stenosis affects the heart's blood supply

Just as your heart is responsible for pumping oxygen-rich blood to your entire body, your heart muscle itself needs oxygen to live. As your heart loses its ability to pump blood effectively because of aortic valve stenosis, it becomes increasingly unable to supply enough oxygen-rich blood to its own muscle.

This oxygen-supply problem occurs progressively, with a series of successive problems. When your heart works harder to pump blood through your narrowed aortic valve, your heart muscle thickens (hypertrophies). Your hypertrophied heart muscle needs extra blood, but there are the same number of coronary arteries supplying blood. Hypertrophied muscle also tends to compress the coronary arteries, restricting the flow of blood.

The relaxation between heartbeats is when your heart muscle receives oxygen from the blood that it just pumped, so a shorter filling period leaves it less time to receive blood. Because of your narrowed valve, your heart actually takes longer to contract (systole), leaving it less time to fill (diastole). Your heart is not pumping blood as effectively through your narrowed aortic valve, so less blood makes it to your heart muscle through your coronary arteries.

This combination of problems leads to a condition called myocardial ischemia, which is when your heart muscle starts to suffer from lack of oxygen (the same problem occurs when you have coronary artery disease). Ischemia can contribute to the failure of the left ventricle that ultimately results from untreated stenosis.

Credits

Last updated:	November 14, 2007
Author:	Robin Parks, MS
Reviewed By:	E. Gregory Thompson, MD - Internal Medicine, George Philippides, MD - Cardiology
Editors:	Kathleen M. Ariss, MS, Pat Truman, MATC