What is it?
In a TMT, the heart is challenged by increasing the heart rate achieved by making the patient walk on treadmill. In certain situations when a patient can't be made to walk, or situations where doing a ECHO may be more useful than seeing the ECG at the target rate, the heart rate is increased by infusion of a drug called Dobutamine.

Dobutamine stress echocardiography is a test in which the reaction of the heart is measured under chemically induced stress, in order to assess the wall motion of the heart muscle. Dobutamine is one of several medications that cause the heart to react as if the person is exercising, though the patient is actually at rest.