A Study to Assess Regadenoson Administration Following an Inadequate Exercise Stress Test as Compared to Regadenoson Alone for Myocardial Perfusion Imaging (MPI) Using Single Photon Emission Computed Tomography (SPECT)

Inclusion Criteria:

• Subjects referred for an exercise or pharmacologic stress test SPECT MPI procedure forthe evaluation of coronary artery disease (CAD) are eligible for study participation.Subjects referred for pharmacologic stress should have a reasonable potential ofattempting exercise stress. Subject must have one of the following:

• a. Past ischemia on any prior imaging stress test without invasive interventionon the artery subtending this territory

• b. Subject with known CAD who have symptoms similar to previous ischemicsymptoms, or recent onset of symptoms or recently worsened symptoms suggestive ofischemia

• c. Diamond Forrester estimated pretest probability of CAD of ≥ 50%

• d. History of most recent coronary artery bypass surgery or most recentpercutaneous coronary intervention (PCI) > 10 years (patients who are > 30 daysbut less than 10 years post coronary artery bypass graft (CABG) or PCI can beincluded if they meet criteria a, b, or e)

• e. Previously demonstrated 100% occlusion by invasive coronary or computedtomography (CT) angiography without successful intervening revascularization asthese foods may alter regadenoson effects

Exclusion Criteria:

• Subject has a clinically significant illness, medical condition, or laboratoryabnormality

• Female subject who is pregnant or lactating

• Subject is on dialysis for end stage renal disease or has a history of glomerularfiltration rate (GFR) < 15 mL/min (calculated using MDRD [Modification of Diet inRenal Disease] formula)

• Subject has a history of coronary revascularization by either PCI or CABG within 1month prior to the rest myocardial perfusion imaging (MPI)

• Subject has a pacemaker or an implantable cardioverter defibrillator (ICD)

• Subject has a history of acute myocardial infarction (MI) or high risk unstable anginawithin 30 days prior to the rest MPI or has had cardiac transplantation

• Subject has uncontrolled hypertension at any point on Visit 2 prior to exercisetesting (i.e., systolic blood pressure (SBP) ≥ 180 or diastolic blood pressure (DBP) ≥ 95 mmHg on two consecutive measurements while at rest).

• Subject has severe aortic stenosis or hypertrophic cardiomyopathy with obstruction orhas decompensated congestive heart failure

• Subject has a history of severe respiratory disease including: asthma, chronicobstructive pulmonary disease (COPD) or other bronchospastic reactive airway diseaseor who is on 24-hour continuous oxygen