Left Bundle Branch Block

I am 48 years old.  During a routine physical my ekg showed that I have left bundle branch block.   While sitting on teh table I did not have it - when I stood up I cinverted to it.  My blood pressure has always been very good (110/65).  My cholesterol has varied between 185 and 200.  I run 3 times a week and am very fit.  Also no significant family history of heart disease.

If my follow up tests show no underlying heart conditions, what is my prognosis?    is tehre a strong lieklihood that this will lead to a shortened life?

[CCF HeartMD6]

Having a left bundle branch block is a sign of some underlying conduction disease -- which can be both serious and benign. There are many patients who have underlying conduction disease which is tolerated throughout life without any difficulties. It sounds as yours is intermittent -- and may be rate related (if your heart rate suddenly increases when you go from sitting --> standing). If so, it is unlikely to cause any serious problems.

Bundle branch blocks can cause problems in some people when they are related to underlying coronary artery disease or have a low ejection-fraction as the 2 ventricles (right and left) do not contract simultaneously.