How much can the EKG's and echo's tell about  any possible narrowing of the arteries?  I have had pvc's for about 4 months, though they are much better than when they first kicked in. 1500/day, now I feel just 10-20 a day.  I ask this because I have over several years experienced some lightheadness after about 30 minutes of raking leaves, mowing lawn with push mower and just yesterday after shovelling the driveway.  45 Years old/F about 30 lbs. overweight but active.  Should I get this checked out.  It goes away after 5 minutes or so.  It has happened almost everytime after doing the lawn, but I play tennis (doubles-but at a high level)and have never felt it.  It seems it is with a steady hard excercise.  No pvc's during it though. Thanks