Rebadawn

After 14 years of suffering from various symptoms, and being told none of them "fit" so must be stress or depression, the specialist who performed my sleep study finally gave me the diagnosis after reviewing my medical records. I was scheduled a TTT to confirm. During the test, my blood pressure stayed stable, however, my heart rate went from 79 to 105 upon standing and did not go back down. I was given nitro spray and BP stayed normal, heart rate went to 125. I did not pass out, but fell asleep. My Cardiologist reported the test as being normal, thus ruling out POTS. I have been experiencing syncope since March (have never passed out in my life before that) and continue to do so. My question is, just how reliable is the TTT?