Anti-gravity Treadmill Exercise in Stress Myocardial Perfusion Imaging

Test arm subjects will exercise according to the Bruce protocol unweighted to 75% of their body weight with additional unweighting to 50% during the test if unable to reach target at 75% weight. Once these subjects have reached their target heart rate on the Bruce protocol, patients will receive the Tc-99m injection as per standard clinical protocol and maintain target heart rate for 1 minute following the injection.

Subjects randomized to the control arm will proceed with the clinical standard regadenoson pharmacological stress SPECT study with adjunctive low-intensity walk on conventional treadmill during regadenoson and Tc-99m injections if tolerated. If they are unable to tolerate any treadmill exercise, they will receive regadenoson and Tc-99m injections at rest. Study patients will have stable systemic blood pressure with readings equal to or greater than 90 mmHg systolic. Other inclusion and exclusion criteria are described in detail below.