Atherosclerotic disease of the coronary artery may simultaneously involve the subclavian artery, and a significant stenosis of the left subclavian artery may result in recurrent myocardial ischemia in patients with patent left internal mammary artery (LIMA) grafts because of 'coronary steal' through the LIMA. Isometric exercise of the left arm may improve myocardial perfusion through vertebral - subclavian steal by flow reversal in the ipsilateral vertebral artery because of the change in the pressure gradient between the circle of Willis and the distal subclavian artery. The present patient had coronary steal through a LIMA after coronary artery bypass surgery and a transient vertebral - subclavian steal with improved myocardial perfusion as a result of exercise of the left arm.