What is a chemical stress cardiac MRI?

Some heart problems only show up when the heart is working hard (or stressed). Stress tests use exercise or chemicals that mimic the effect of exercise on the heart. Exercise stress is not feasible with cardiac MRI because you have to lie still in the machine throughout the test. Studies show that cardiac MRI chemical stress tests are accurate and they may be more widely used in the future.1 Currently, this test is not done very often because it is still very new and there are some safety issues that do not exist with other types of chemical stress tests. The doctor is not in the room with you during the test, and it may not be immediately obvious if you experience problems because you are hidden inside the machine.