The left ventricular end diastolic volume changes with exercise have been characterized in patients with mitral stenosis, aortic stenosis, hypertrophic cardiomyopathy, hypertensive heart and Adriamycin induced cardiomyopathy in our laboratory by using radionuclide angiography for the past 4 years. Exercise induced end diastolic volume changes are as important variables as ejection fraction change to determine stroke volume and cardiac output increase with exercise. We can calculate the exercise reserve or cardiac reserve by using the formula we designed. For the next two years, I plan to characterize the exercise induced EDV changes in relation to stroke volume and cardiac output changes in coronary artery disease. The exercise or cardiac reserve may be as important as, or more important than, exercise induced ST-T wave changes or EF changes in coronary artery disease for prognosis.