often used when transthoracic images are suboptimal and when a clearer and more precise image is needed for assessment. This test is performed in the presence of a cardiologist, registered nurse, and ultrasound technologist. Conscious sedation and/or localized numbing medication may be used to make the patient more comfortable during the procedure. Stress echocardiography A stress echocardiogram, also known as a stress echo, uses ultrasound imaging of the heart to assess the wall motion in response to physical stress. First, images of the heart are taken "at rest" to acquire a baseline of the patient's wall motion at a resting heart rate. The patient then walks on a treadmill or uses another exercise modality to increase the heart rate to his or her target heart rate, or 85% of the age-predicted maximum heart rate (220 − patient's age). Finally, images of the heart are taken "at stress" to assess wall motion at the peak heart rate. A stress echo assesses wall motion of the heart; it does not, however, create an image of the coronary arteries directly. Ischemia of one or more coronary arteries could cause a wall motion abnormality, which could indicate coronary artery disease. The gold standard test to directly create an image of the coronary arteries and directly assess for stenosis or occlusion is a cardiac catheterization. A stress echo is not invasive and is performed in the presence of a licensed medical professional, such as a cardiologist, and a cardiac sonographer. Intracardiac echocardiography Intracardiac echocardiography (ICE) is specialized form of echocardiography that uses catheters to insert the ultrasound probe inside the heart to view structures in 2D. ICE is often used as a part of the cardiac procedure of crossing the interatrial septum with a transseptal puncture to permit catheter access from the right atrium to the left atrium. ICE has the benefit over transthoracic echocardiography in that an operator who is performing a sterile procedure can also operate the ICE catheter and ICE is not limited to visibility problems that can arise with transthoracic echo. ICE is often inserted through the femoral vein and into the right atrium. From the right atrium, visualization of the interatrial septum, all four cardiac chambers, all four valves, and the pericardial space (for an effusion) can be readily visualized. Intravascular ultrasound Intravascular ultrasound (IVUS) is a specialized form of echocardiography that uses a catheter to insert the ultrasound probe