It sounds to me like your provider was performing a Brugada Study.
This test is performed to see if the patient has Brugada syndrome.
This syndrome most typically affects individuals of asian background and what happens is they develop atrial fibrillation and/or ventricular fibrillation only at night while they are sleeping. Otherwise there are almost no signs or symptoms of the condition otherwise, and it can be fatal.
Brugada studies are done some times in the EP lab where the patient is given an infusion of isuprel while they are connected to a 12 lead EKG. Before and after the infusion, the provider checks for rythmn changes in leads V1 and V2 that hallmark the syndrome. If the provider can induce the afib/vfib via the isuprel, he/she now has a critical piece of information to substantiate the need for an ICD implant.
When this is all that the provider performs, there is no CPT code to represent the service. You cannot bill 93623. Trust me. I have tried.
What I find interesting though is this RV pacing. Maybe your provider elected to do this to speed up the process of waiting to see if the arrhtymia would pop up. Often times you have to wait for a few hours in the lab during these Brugada studies, because the arrhythmia really pops up sporadically without alot of rhyme or reason.
So if you provider was pacing in order to attempt to induce the arrthymia, I would bill 93618, as long as it is properly documented.
You still won't be able to charge anything additionally for the isuprel administration. But at least now you have a code that makes sense for the procedure performed.
I wouldn't bill for a limited diagnostic EP Study (93603/93612) unless you see evidence of RV recording (documentation of HV interval data) and RV pacing (ventricular extrastimulus testing/pacing) in your documentation. Then you could bill these elements in addition to the 93618, as long as you feel it is all properly documented.