You will be sleeping lightly during the procedure, but you might experience angina pain or slight discomfort in your chest. If this is the case, additional pain medication, such as morphine, can be administered via IV. Usually the discomfort lasts only a few seconds and goes away as soon as the balloon is deflated. You should inform the cardiologist who is performing the procedure if pain or discomfort occurs.

Reference:

1. Cardiac catheterization. (n.d.). Retrieved from https://www.mountsinai.org/health-library/tests/cardiac-catheterization