Binodenoson (an experimental drug) and adenosine (an FDA-approved drug that is currently used by doctors) are used to increase blood flow to the heart just like when a person exercises on a treadmill. Using imaging techniques, this increased blood flow can help determine if areas of the heart are not getting enough blood and oxygen during exercise. The purpose of the study is to determine if binodenoson is as good as adenosine in determining if there are areas of the heart not getting enough oxygen when blood flow to the heart is increased.