I am a 57 yr. old female with Diabetes, High Blood Pressure and I am 2 yrs cancer free from kidney cancer. My dr. says I now have Inappropraite Sinus Tachycardia (IST) because my heartrate is up to 150. I was on a 30 heart monitor and I had a stress test done.The results of the monitor showed I have IST. My stress test came out normal. He says I need a procedure to close an extra pathway leading from my heart. Its an outpatient procedure. They go up the groin to the pathway and burn it closed. The bad thing is that if they tap the main point, I may have to have a pacemaker inserted. Is it worth the risk? Can I have a heart attack if I leave it alone? Will this IST get worse if left untreated?