Can you tell me what a aorta venous malformation is?

Ateriovenous Malform: Avm for short, a blood vessel abnormality in the brain:small capillaries fail to form in an are of the brain resulting in an abnormal tangle of vessels like a "can of worms" about half of these go on to burst causing a stroke. Unfortunately that is the most common symptom. They may cause seizures, or headaches or changes in speech, vision or movement. My avm was of the acute bleed type.