I have had a EKG, echo, stress eco, thyroid labs, 2 stress tests
, holter monitor and 30 day event monitor. My stress test
and holter showed left
bundle branch block (LBBB) when my heart would reach 120-130's. This happen with very mild exertion (walking up stairs, walking up small hill, even getting dressed) which is far from my activity level prior to this. At first my Dr mentioned a rate dependent LBBB.