We propose to assess regional myocardial function using gated blood pool imaging acquired by a tomographic technique at rest and during stress in patients with myocardial ischemia (coronary artery disease, hypertrophic cardiomyopathy and microvascular angina). Gender differences in response to exercise and pharmacologic stress will also be evaluated. Normal subjects will be studied in order to establish a control database. Current methods of gated blood pool studies use planar imaging, with its attendant limitations; poor resolution and inadequate separation of the myocardial segments, only one view assessed during exercise and superimposition of overlying structures. Tomographic imaging has the advantages of reconstructing 3-dimensional data of the entire heart with the ability to improve segmental resolution and separate overlapping structures, potentially resulting in increased sensitivity and specificity for detection of disease.