Electrophysiologic Studies (EPS) By Thomas Cascino, MD, MSc, Michigan Medicine, University of Michigan; Michael J Shea, MD, Michigan Medicine at the University of Michigan Reviewed / Revised Jul 2021 | Modified Sep 2022 View Patient Education Topic Resources Electrophysiologic Study In electrophysiologic studies (EPS), recording and stimulating electrodes are inserted into all 4 cardiac chambers via right - or left-sided cardiac catheterization.