An echocardiogram is a diagnostic procedure which allows physicians to observe the structure and functioning of the heart without invasive surgery or other more complicated procedures such as a cardiac catheterization. When a patient goes for an echo, a clear, jelly-like substance is applied to the chest. A device that looks somewhat like a plastic knob will then be gently pressed against the chest. This device sends high-frequency sound waves through the body that a computer then uses to produce images of the heart. The procedure is painless and generally takes forty minutes to one hour.