I apparently have the Drs. at Hopkins and some of the top heart pathologists, from Duke to Mayo, stumped but there might be a Dr. House or someone in cyberspace that might have an insight, so here goes. The noticable symptoms occurred after giving a pint of blood at local blood bank. Play active racqueball 2-3/week, noticed shortness of breath and fatigue. 56 years young with great health history. Stress test showed slow heart rate (40's bpm) and conductive block, echo & MRI showed thicken septum 3 c.m. (1 c.m. normal), with no distintive tumor. Negative for Lyme and other tick diseases. Took antibodic regiment as precaution- no results. Heart biopsy of septum area inconclusive; lymphosysts did not indicate infection or lymphoma and pet scan did not show any cancers or spread from heart. One more MRI this week to see if the septum has changed (heart rate still in the 40's). Drs. might try steriods before pacemaker. I am probably the Lotto winner of the wrong prize but wanted to give the internet a shot. I know I am in the best hands, but if anyone has a clue please feel free to chime in.