Has anybody out there had an abnormal ECG following a healthscreen. The cardiologist wants me to have echocardiogram which I am happy with, but what I am worried about is the thallium scan (radio-active stuff pumped into you to show flood flow through heart). I can still run as I have never had any chest pain or palpatations and the cardiologist thinks that it is unlikely he will find a problem. I have run for over 20 years, quite competitively. Surely running cannot damage the heart muscle?