I have had problems with heart racing for 11 years, have seen numerous cardiologists including ep's, and one of the arrhythmias is sinus tach, my heart will slowly speed up to 140-160, was faster off meds, 160-200. It lasts from a few minutes to over an hour and will slow down and increase during this time. usually breaks when it goes below 80 again. That is even though on atenenol, ep study 11 years ago showed hyper sensitive sinus node could find nothing else. I also get episodes of blurry vision at times, tingling in both legs at times, an uncomfortable feeling of pulse pounding in feet and a rushing sound in ears with heart beat at times. This has just developed in the last year. I also have sinus arrhythmia, and also an atrial tachycardia, short lived episodes lasting less than 20 seconds, pac's hundreds a day and rare pvc's. atenenol causes bradycardia (50's) even though on low dose 25mlg. It started after a trip to the moutains and I came home and had symptoms of weakness and then a cold. I see a cardio 2 times a year and she says I won't die from this. My heart races at least one a week for an hour or less, is this dangerous? Could all this be some kind of dysautonomia. Just about any drug iv will cause my heart to race. Once a gp mentioned dysautonomia, how would I determine if that is the problem and what kind of doctor would I see? Quality of life is not very good. Have tried almost all of the heart drugs, none have totally controlled the racing. most have made it worse or caused pauses in heart beat. I am 58 years old, thin and exercise daily. All arrhythmia problems have been captured many times over the years, also some episodes of junctional ryhthm and accelerated junctional rhythm. Never had any awareness of heart beat in my life before this began at 48 years old. Recently was hospitalized for a day for vertigo. thank you