Non-invasive tests are defined as those medical procedures which does not penetrate or break the skin or a body cavity, i.e., it doesn't require an (invasive) incision into the body.

Invasive tests involve inserting catheters into the blood vessels of the heart in order to get a closer look at the coronary arteries or to stimulate and test the electrical system of the heart.

There are other tests which are done in investigating the Heart.