EKG worries ? Had a EKG yesterday and it showed a 1st degree AV block. Should I be worried ? 48, Male, extremley fit. no smoking, drinking or major health issues. I run 20 miles per week for past 30 years Was dehydrated before the EKG , and take 12mcg of hydroclrothyzide daily. Could this reading be a result of dehydration/low potassium and the HB med? This is the first time a EKG has ever shown this. Also have been told this condition is very common in athletes. Need some re-assurance from people who know about these things.