An echocardiogram is an ultrasound of the heart. An echocardiogram enables a doctor to examine your heart valves, determine the size of your heart, and assess how well it is functioning. The test can estimate how forcefully your heart is pumping blood, and can spot areas of the heart wall that have been injured by a previous heart attack or some other cause. No preparation is necessary. You wear a gown and lie on a table. After squirting some clear jelly onto your chest to help the ultrasound sensor slide around easily, a technician places the sensor (which looks like a microphone) against your skin.
A picture of your heart appears on a video screen, and the technician slides the sensor back and forth on your chest to see different views of your heart. At times the volume from the machine might be turned on, transmitting a whooshing noise; this represents the sound of your heart beating and blood flowing.