Hello, For the past month I ve had a really high heart rate from 140 to 229. They did a 24 hour Holter and it showed SVT and Inappropriate Sinus tachychardia. I was put on propanolol. Today I ve had 3 episodes of tachychardia, I have eye twitching, and getting panic attacks from the fast heart. Does SVT and IST cause all these symptoms? Why is the med not helping? What can be done to stop the tachycardia. I eat healthy: No gluten, no dairy, no caffeine, and no soy.