The cure rates for AVNRT RFA are very high with recurrences in less than 5%. Many people have a heart rate going up to 120 or higher in the first minute of exercise, especially if they are not exercising regularly, or are tensed about the test. It is also very easy to detect on your treadmill tracings that the increase in heart rate is not coming from an abnormal source. If your doctor did not mention any abnormality you can take it for granted that the increase in rate was from the normal SA node that happens during exercise. I personally feel that it is a great decision to get an AVNRT ablated because the results are so good and you can avoid a life time of medications.