my son appox. 8months ago developed svt, we had test after test including a cardiac cath. electrical study, which came out only that he seems to be releasing to much epi into his system they were'nt able to do a ablation because they couldn't locate the source of the problem. we have also tested for any tumors that could cause this but those where also neg. We have tried differant medications verapamil, amnioadrone, which didn't work now were are on atenalol which only works some of the time he still has break through SVT multiple times a week is there any thing else we can do? the atenalol, because he has asthma quite severe has cause him to now have lower PFT then he has ever had before buts hes handleing that part okay.its the only drug that has help some so we are continueing to take it with our doc watching his lungs close. prior to all of this he was able to play sports and do just about any thing but now, a small amout of exercise will set him off, with chest pain, sob, and being close to passing out and a hrt rate of 200bpm.... Should I keep looking for an answer and better treatment.has anyone seen this before and found somehing that works long term. any hepl or info would be great.