In patients who cannot exercise due to vascular or musculo-skeletal problems (e.g. back pain, arthritis, etc.) an injection of intravenous persantine may be used to "stress" the heart. Thallium or sestamibi may then be administered and the heart scanned with a special camera to identify areas of reduced coronary artery blood flow. Persantine may not be given to patients with asthma or who are on asthma medications. Side effects of persantine include headaches, flushing, chest pain and shortness of breath. These effects are readily reversed with the antidote, aminophylline.