To exam the feasibility and accuracy of Regadenoson real time perfusion (RTPE) Imaging during vasodilator stress with Regadenoson for detection of significant coronary artery disease (CAD) in patients scheduled to undergo coronary angiography.

To exam the feasibility and accuracy of RTPE during vasodilator stress with 400micrograms of the adenosine receptor (A2A) agonist Regadenoson for detection of significant coronary artery disease (CAD) in patients scheduled to undergo coronary angiography. Sensitivity, specificity , and accuracy of perfusion and wall motion analysis to identify a coronary stenosis> 50% in diameter by quantitive angiography will be analyzed

Inclusion Criteria:

• Male or female. Age ≥30 years.
• Resting Left Ventricular Ejection Fraction > 40% using Simpson's biplane measurement.
• Scheduled for coronary angiography within 30 days of the Regadenoson stress test.
• Negative urine pregnancy test within 2 hours of ultrasound contrast administration required of females of childbearing age unless post-menopausal or with evidence of surgical sterilization.
• Be conscious and coherent, and able to communicate effectively with trial personnel.
• Agreeable to undergo the additional stress test and coronary angiography
• Have at least an intermediate likelihood of coronary disease based on the following clinical profile
• Good apical echo images with at least 50% of each coronary artery territory well visualized.

Exclusion Criteria:

• Known or suspected hypersensitivity to ultrasound contrast agent used for the study.
• Pregnancy or lactation.
• Complicated hemodynamic instability (i.e., New York Heart Association (NYHA) Class IV heart failure, unstable angina at rest despite medical therapy).
• Life expectancy of less than two months or terminally ill.
• Congestive (idiopathic) or hypertrophic cardiomyopathy.
• Known left main disease.
• Heart transplant recipient, hypertrophic cardiomyopathy, acute myo- or pericarditis.
• Resting Left Ventricular Ejection Fraction < 40%
• Large inducible perfusion defects or wall motion abnormalities during prior stress imaging study associated with left ventricular cavity dilatation.
• Early positive treadmill EKG within the first stage of the test.
• History of >1st degree heart block, sick sinus syndrome or high grade atrioventricular (AV) block without a pacemaker.
• Dipyridamole use within 30 hours of stress test, or consumption of methylxanthines within 12 hours, or use of sublingual nitroglycerin within two hours.
• Participation In another investigational study within one month of this study.

1 hour observation

Non-serious adverse persisted no more than 5 minutes for chest pain, shortness of breath & back pain. Headaches were reported within 1 hour.