I wouldn't get lost on a single EKG that does not demonstrate acute ischemic morphologic pattern, especially when the previous had similar morphology.
What you're describing sounds to be an easy syncope admission. First, forget all the rules and just listen to your clinical gestalt. Are you really going to send an elderly NH patient home who woke up on the floor, is a poor historian, is certain to have several comorbidities that probably include CAD and can't remember anything about what happened? Of course not. What about one with a troponinemia and a technically "abnormal EKG"? Ditto. Did she fall? Did she seize? Did she have an arrhythmia? Is she having a silent MI? Who knows, and it sounds like she certainly can't give you a great history. It smells like syncope and that's the direction I'd take.
I don't have all your history but she probably meets San Fran Syncope rules quite easily and you could fudge the "abnormal EKG criteria" as potential ischemic morphology. Especially in light of a troponinemia. Even if she doesn't meet San Fran Syncope, she meets OESIL (look it up). That's another study I use for some of these elderly pt's that have syncope and don't meet the criteria but my gut says "no", it includes a few other factors such as age, syncope without prodrome, and CAD (not just CHF). There's also a good LLSA article that I read recently and can't remember where that tried to narrow down these nebulous EKG changes that seem to indicate from the latest literature: anything non sinus, anything LBBB or partial (hemiblock), anything ischemic, etc.. I use OESIL study for those outliers where it validates my gestalt. All these rule systems essentially should validate what your clinical intuition is telling you in the first place.
So (after you've worked her up and made sure she doesn't have hip fx, head bleed, etc...), you've got a pt that's probably both San Fran Syncope positive and OESIL positive, "abnormal" EKG and troponinemia of uncertain significance. NSTEMI? Unsure, because it sounds like she really can't tell you whether she's having any ACS type sx or not but in light of the syncope, it's a possibility. Obviously, she gets ASA. I could easily admit and wait for 2nd trop at 4h and if elevated heparinize her or you could just start the heparin now and stop after 2nd or 3rd enzyme vs let cards/medicine take her off it when they get around to seeing her. I'd leave it up to medicine and think both are not unreasonable approaches.
Admit to tele. Turn over the room. Next pt. Let cards mentally masturbate over the significance of a chronic lateral ST depression with no other changes. Either way, without the troponin, it's an easy syncope admission which you should recognize about 2 minutes into the pt encounter in this case by the sound of it. NSTEMI could also be easily justified as an admitting diagnosis along with the syncope in light of the lack of pt ability to provide more of a history/symptomatology.
