Sorry about the delay in replying, I was a bit too brain fried to get my head around this yesterday.

I have had some testing, the cardiologist confirmed IST. I have had ambulatory BP testing but if I was moving it registered errors because its too labile to measure and if I stood still my BP returned to normal. Consequently all they got was normal results and a load of errors. I have been tested for diabetes and tested negative.

I had a tilt table test when I first became symptomatic years ago which was negative as I was in a remission period and my condition was primarily cardiac and OH barely noticeable at the time. (I suspect this was because I get highly transient multiple blood pressure drops but only when moving. I have managed to have orthostatic hypotension measured since when I discovered I could prevent the normally rapid bounce back by maintaining an unstable posture and rocked back on my heels when being measured after standing.) Of course no positive tilt table result or ambulatory BP = no orthostatic hypotension. This resulted in an autonomic disorder being discounted (prior to the cardiologist result) and my GP promptly beta blocked me to deal with the tachycardia resulting in a catastrophic vaso-vagal syncope that caused fitting and left me twitching for hours afterwards.

Consequently I am mistrustful of overly reductive one-size-fits-all testing. I cannot be sure many of my symptoms are going to be detectable on a given day. Its safer for doctors to be uncertain of my condition than to perform a test, get me on a good day, discount my reported symptom and come close to killing me with dangerously inappropriate medication.

So I have spent the last few years researching all the various possibilities, MSA PAF AAG etc. and am very familiar with the testing regimes from clonidine tolerance to pupil response and even waded through Roger Bannisters textbook on Autonomic Failure. I have a medico-legal background so although my knowledge of medicine is rudimentary to say the least having mostly dealt with industrial accidents PTSD, orthopaedic injuries and mesothelioma I can at least digest the basics although I'll admit autonomic neurology is a stretch. I pursued the cardiological component of my condition because I purchased my own testing equipment referred to the book, knew it was almost always present, indisputable and easily confirmed, and so it proved to be. It took me 5 years from the detection of a resting heart rate of 110 to get IST confirmed by a cardiologist, by which time I had long since worked it out for myself. Symptoms like the sleep disorders are highly sporadic and happen for a few weeks 3 or 4 times a year, so I've no idea whether or not they will be present if I was to organise a sleep study and wait several months for the appointment.

What I am after here is answers to questions like does anyone else have the sort of highly transient orthostatic hypotension I experience, if so can I rely on a tilt table test to detect them? Do I need to be having an attack for AAG bloodwork to detect the problems? And what have people with conditions similar to mine been diagnosed with? My quality of life is considerably better relying on the many coping mechanisms I have developed myself and doing my best to enjoy life as best I can, than embark on another round of symptom exacerbating, adversarial medicine, and risk another near fatal cock up. So I am hoping to gather as much information as possible, narrow it down as much as possible so I know what testing I can undertake without making my situation worse.

Thanks again for your reply