A few community members have expressed interest in hearing about what my experience was like getting testing done at Cleveland Clinic, so I'll try to give a brief overview here. They vary the testing depending on how the results of things go for each patient, so others who have been there please feel free to add on your own experiences.
My first trip up to Cleveland was just to meet with the doctor and go over my history and medical records and have a physical exam. I saw a cardiologist who specializes in this field; the only test they ran that day was an EKG.
For my second trip, I asked that they line up as much testing in one day as possible rather than having us make repeated trips there. Five tests were scheduled: tilt table test, blood volume and hemodynamics, heart rate variability, autonomic reflex, and QSART. Fasting was required briefly prior to the first two tests. In order for the QSART (and perhaps some of the other autonomic tests??) to be accurate, I had to be off some of my medications for 48 hours prior. If I had done the tilt and hemodynamic testing separately on one day and come back for the others if needed, I would not have had to discontinue meds for that visit.
I won't describe the tilt table test much because many have already had one, and there is plenty of information about them available in other threads here and in various places online. After the tilt the doctor met with us to briefly go over the results. We'd been told that depending on the results of the tilt, I would either only need the first two tests scheduled for the day or would be going ahead with all five of them. The doctor said we would be going ahead with all five.
The blood volume and hemodynamic testing is a form of nuclear medicine. They use the IV that was placed in your arm for the tilt. Many vials of blood are drawn, and isotopes are injected which are then traced as they move through your bloodstream. To the best of my memory, they then can tell your ejection fraction of your heart and see if your blood is pooling (they sit you up for part of the test, but you don't have to stand). The "blood volume" part of this is figuring out if you are hypovolemic (low blood volume). Essentially, as one of the nurses helping with this test explained to me "the tilt told us what, this is going to tell us why." If I understand correctly, it will show in a mechanical sense why your blood pressure dropped on a tilt, for example. (I say "in a mechanical sense" because this is one layer of the "why," but once you answer that you are left with further layers, such as why are you hypovolemic in the first place or why are you having issues with vasoconstriction, etc.) The test is long--about 2 hours--but you are lying down comfortably for most of it. There is some slight discomfort with some of the injections into the IV as a few of them have to be done very rapidly, but it is definitely tolerable. I was still having some symptoms from getting over the tilt and from being off my meds, but the nurses were very accommodating in trying to make me as comfortable as possible.
I was given something to eat since the rest of the testing did not require fasting. They had yogurt, fresh fruit, crackers and peanut butter, and juice. (You may want to bring something from home if you want something more substantial after fasting, or would prefer to try to salt load a bit to recover from the tilt.)
The heart rate variability testing and autonomic reflex testing were both in the same room I think?? It's kind of a blur to me and I hope I'm not messing this up, but I'll do my best to figure out which was which and someone can correct me if they think I've got it wrong. Hey, I was off half my meds and was pretty out of it by that point in the day, LOL. At any rate, I had to lie down with a special cuff around my waist that detected my breathing and basically just lie still and breathe normally. You'd think that would be simple, but after someone goes through a lengthy set of instructions about not taking a deep breath, not skipping a breath, not holding your breath, not breathing too shallow or slow, just breathing *normal* ... you realize you're too focused on your breathing and you can't remember how you normally breathe anymore because you're thinking too hard. :-p At any rate, you lie there and breathe for a while "normally," then you're asked to take deep breaths according to certain instructions and you do that. Then you stand up and breathe normally. I think that's the whole heart rate variability part. The autonomic reflex part, I think, is where you have to blow into a little tube that's basically pressurized until they tell you to stop and let your breath out and breathe normal (the Valsalva maneuver). You're wearing a miniature blood pressure cuff on your finger that measures your blood pressure continuously beat-to-beat. If that test is normal, you don't have to do the rest of the autonomic reflex tests. Mine was, so I can't describe the rest of the tests for everyone, sorry. I don't have much information on these tests, mostly because I was eating while he was setting up and you're not allowed to talk at all during the test so I didn't get to ask a bunch of questions. Sorry. :-/ Ooh, here's what Cleveland Clinic has to say about heart rate variability--if you're interested, you can get the details straight from the horse's mouth:
http://www.ccjm.org/content/76/Suppl_2/S37.full
The QSART (quantitative sudomotor axon reflex testing) involves having these little electrode things strapped to your wrist, leg, ankle, and foot. They send out little pulses that supposedly stimulate tiny areas to sweat, although the technician said you wouldn't notice it because it's such a small area. Yet again, you pretty much just lie still. This one doesn't take long, only about 10 minutes once they get going. The sensation from the electrodes is weird but I wouldn't say it's painful. It did leave big red circles on my skin that took about 5-6 hours to fade; I have sensitive skin, your mileage may vary. This test is supposed to indicate if there may be problems with peripheral autonomic nervous system, in which case I believe you need to have further testing (i.e. biopsy).
Once the tests are reviewed by the appropriate specialists there I will hear back about my results, and whether I need to come back to meet with an autonomic neurologist or have a biopsy or other further testing. The only results we got the same day was just the general diagnosis from the tilt (which wasn't news, per se, because this wasn't my first tilt).
Overall, we've had a very positive experience there. The doctor has been very helpful, his secretary has bent over backwards to answer every question and never makes me feel guilty for calling back repeatedly, the nurses are very kind, etc. They were good about telling my S.O. how long each round of testing was going to take so he knew whether to stay close by or whether he had time to go grab a bite to eat and come back. Do be prepared for some rather pricey parking: our first trip out there just to meet with the doctor I think we spent $7 to park in the garage, and for the day of testing it was closer to $20. Handicapped spaces in the garage seem to be easy to find in the early AM, whereas you may have to be a bit of a vulture to get one later in the day.
One more note: they don't have it yet, but CC is working on building the facilities for TST (thermoregulatory sweat testing). This is another form of autonomic testing and will be a nice complement to the testing facilities they already have available. We will try to stay abreast of when this is completed to let everyone know when it is available there.