It is less expensive than MUGA and more clinics have the equipment to do an echo. There is no dye or radioactive tracer used. There are no needles and no pain. Like any test, it's not perfect.
Echos use ultrasound.
The sound waves are reflected by the heart walls and valves back through the transducer to the machine. High-powered software puts together a picture of your heart from the returned sound for the doctor to examine. That same software also gives a huge amount of information about your heart's function through the numbers on the monitor screen. The whole test is recorded on video tape. This test can be done in your doctor's office if he has the equipment, but it is usually done in a clinic or hospital.