Just back from my tilt table test for Postural Tachycardia Syndrome.
Started by soaking my hands in hot water for 15 minutes because they were blue and the sensor pads couldn't pick up a pulse! Then 20 minutes stood upright whilst being monitored and observed by the consultant. A squirt of GTN under the tongue and some more monitoring.
Result - my pulse rose by about 20 beats per minute on standing. I "failed" the GTN challenge, as my BP dropped to 80/50, so they had to stop the test at this point.
Conclusion = I do have issues with BP and heart rate regulation, but do not meet the criteria for a diagnosis of POTS (I would need a rise of >30 bpm for this). Its possible that I would meet the criteria if I came off B blockers, but unless there's a pressing need to get such a diagnosis, the outcome is simply to continue on B blockers and otherwise manage the regulation problems conservatively (drink plenty of fluids, don't stand up for long periods etc etc)
The test was mildly uncomfortable but that's all. And I got a cup of tea at the end.