Katie - Not all echocardiograms require an IV. In fact, most do not. Doppler echo is a technique in which the machine determines direction of blood flow and indicates it with blue/red colors on the picture. This does not require an IV; it just analyzes the way the sound waves bounce off the blood cells.
However, in some cases, your echocardiographer may want to use something called "contrast" during your echo study. The two common brands are Optison and Definity
. If so, an IV would be needed to inject the contrast into your bloodstream. This is commonly used in some centers during stress
echos to help identify abnormalities in the way the heart squeezes.
Sometimes, a "bubble study" is requested to look for abnormal holes in the heart. This is most commonly done to look for a PFO or an ASD. In these situations, an IV would be necessary as well. Hope that helps!