What symptoms do you have with an avm?

Depends on location. Avms may present with a bleed, which may be manifest as a headache or alteration in level of consciousness. Patients may also present with a seizure. This is from the ischemia to the surrounding brain as most of the blood to the area is going to the avm rather than the brain. Focal motor deficits may occur if the avm causes adjacent brain (motor area) to suffer from a shunting of blood to the avm.
Multiple or none. Many avm's are silent and people never know they have them until they bleed. 30% of people with avm's will present with seizures. You may have headaches, strokes, visual symptoms, weakness, or other symptoms.