what is arterial venous malfunction
Normal and abnormal blood vessels. In a brain AVM, blood passes directly from arteries to veins via a tangle of abnormal blood vessels. A brain arteriovenous malformation (AVM) is a tangle of abnormal blood vessels connecting arteries and veins in the brain. The arteries are responsible for taking oxygen-rich blood from the heart to the brain. Veins carry the oxygen-depleted blood back to the lungs and heart.