Echo is a procedure that determines how well your heart and blood vessels are working. Echo can detect possible blood clots inside the heart, fluid buildup in the pericardium (the sac around the heart), and problems with the aorta. The aorta is the main artery that carries oxygen-rich blood from your heart to your body. In TMT, an ECG is done while you are doing exercise. In this test, the patient walks on a treadmill as per the protocol of the test.