The goal of this clinical research study is to compare regadenoson nuclear stress testing with echocardiography strain measurements (an ultrasound imaging method that measures hearts function) in detecting coronary artery disease.

If you agree to take part in this study, you will have the echocardiography strain measurement performed. This will be done while you lie on an exam table. An ultrasound technician will apply a vaseline-like gel to your chest and will take the measurements by holding a transducer (a device that resembles a microphone) against your chest, sliding it back and forth. This will take about 10 minutes.

After the resting strain measurement is done, you will have the first set of nuclear images. This will be done just like the echocardiography strain measurement. Once these images are completed, you will be given regadenoson by vein over about 10 seconds. Within 2 to 4 minutes of receiving the regadenoson, measurements will be repeated. These measurements will take about 2 minutes to complete. At about 30 minutes after regadenoson was given, you will have the final images for the nuclear portion of the testing (this is the usual timing for nuclear images after regadenoson).

You will receive the same treatment during your stress test, including the same amount of regadenoson, as you would if you did not take part in this study. Some participants may be asked to allow a repeat of the strain measurements that will include an additional dose of regadenoson if the first set of images are not good enough and additional images may be taken.

Length of Study:

Your participation on this study will be over 30 days after the tests OR after surgery, whichever occurs later. Researchers will collect information from your medical record for up to 30 days after your tests.

If you have surgery or are hospitalized in the 30 days after the tests, you will be called and asked about any problems you have been having. This call should take about 10 minutes.

This is an investigational study. Regadenoson is FDA approved and is routinely used for nuclear perfusion stress testing. The use of strain measurement during an echocardiogram to detect coronary disease is investigational.

Up to 300 participants will be enrolled in this study. All will take part at MD Anderson.

Inclusion Criteria:

1. Cancer patients who are scheduled for (perfusion) nuclear stress testing using regadenoson as stress agent.
2. Indications for stress testing is either: -as part of a pre-operative evaluation prior to a planned cancer related surgery that is considered to be at least of intermediate risk (Intra-peritoneal, intra-thoracic, head and neck surgery, orthopedic or prostate surgery) OR -as an evaluation in the cardiology clinic for symptoms described in a cardiology consult as typical angina, or of significant suspicion for coronary disease or symptoms described as likely of a cardiac/coronary etiology.
3. Patients with a history of LV dysfunction will be still candidates for enrollment in the study if they have documented LVEF recovery (most recent documented LVEF of 50% or higher) for at least 6 months prior to SPECT regardless of current cardiac medication regimen.
4. Age 18 - 80 years.

Exclusion Criteria:

1. Patients consented for the trial that on the baseline 2D study have poor acoustic echo windows (i.e. a reader is unable to see in definition 2 or more segments from the apical views) will not be eligible to continue in the trial and peak hyperemia images will not be obtained.
2. Any patient with tachycardia defined as HR of 100 or higher at the day of SPECT will not be eligible for this study.
3. Second- or third- degree AV block.
4. Sinus node dysfunction.
5. Patients with allergy to regadenoson.
6. Patients with LBBB and/or artificial pacemaker.

30 days after surgery