I'm confused. When I was in my 40's over ten years ago it was uncovered that I have a left bundle branch block. I never had any symptoms and in fact was still doing competitive masters swimming doing very challenging workouts and had strong breath recovery. In a normal physical the physician ran an stress test and noticed the irregularity. I had a low ejection fraction upon further investigation but again I've never noticed any discomfort or shortness of breath, really any issues with intense exercise. I had a heart catheterization at the time and the cardiologist said I'm fine and it is like having green eyes instead of blue, nothing to worry about I have a healthy heart muscle. I still worry because I never seem to find any encouraging information about LBBB.