has anyone have much experience with these? ive had them for the past year or so and finally got them diagnosed. ever since theyve begun, ive noticed the quality of my running has went down. my theory (i was a p.e. major, so im not the smartest guy) is that with pvc's, your heart pumps less blood, which means less oxygen. the doctor also gave me a 14 day sample of the beta blocker called toprol-xl. ive started training to hopefully run under 2:22 at chicago in the fall and was wondering what other runners experiences were with this condition.