 Sometimes a "series" of EPS drug trials must be conducted to enable the cardiologist to select the one regimen for long-term treatment that best prevents or slows the development of VT or VF following PES.Such studies may also be conducted in the presence of a newly implanted or newly replaced cardiac pacemaker or AICD.A specialist in cardiac electrophysiology is known as a cardiac electrophysiologist, or (more commonly) simply an electrophysiologist.