THERAPEUTIC PROCEDURES << BACK Intracardiac Ultrasound Intracardiac ultrasound allow the physician to see the inner surface of the heart and valves to determine if there is abnormal structure, infection, or any problems with the inner lining of the heart. Intracardiac ultrasound is an invasive test using a catheter with a sound probe on the end. The catheter is threaded through the artery in the groin and fed through the arteries until it reaches the heart. High-frequency sound waves are then used to create precise images of the interior heart surface. The test takes about an hour to perform.