Prospective Analysis and Comparison of Stress Echo to Real-Time Myocardial Contrast Stress Echo

Inclusion Criteria: * Male or female * Age \> 19 years * Scheduled for a stress echocardiography * Are conscious and coherent, and able to communicate effectively with trial personnel * For troponin evaluation, only hospitalized patients who had a troponin level drawn in the morning of and prior to stress echocardiogram will be included. Exclusion Criteria: * Pregnant and breast feeding women are excluded from participation because of the possibility of a bias as CSE is routinely used in pregnant patients secondary to lack of human studies to determine the fetal risk of use of Definity. * Age \< 19 years old * Known or suspected hypersensitivity to ultrasound contrast agents or other drugs used for the study * Possibility that potential subject may be pregnant * Studies where RT-MCE was specifically requested by the ordering physician