Subclavian steal syndrome happens when the subclavian artery is narrowed upstream of the brain. When you use that arm, blood “steals” backward from the brain to keep the arm alive, causing brief but scary brain symptoms. Arm fatigue is the first clue. The hand on the affected side tires quickly—gripping groceries or brushing hair feels like a workout. Dizzy spells or blurred vision show up when you raise or use the arm. The room may spin, or letters blur for a few seconds, then clear. Neck or shoulder ache can throb on the same side, especially after overhead activity. Blood... Learn more