Gary,

Thanks for your question.  There are two types of bundle branch block: left bundle and right bundle branch block.  When the normal electrical current travels through the heart, it splits into two branches (left and right bundles) before it causes the two large chambers to contract and pump blood.  When one or the other branch is delayed, there is a characteristic appearance on the electrocardiogram.  This delay is a small fraction of a second and does not affect the pumping action of the heart. 

Bundle branch blocks are often found on routine electrocardiograms, and sometimes occur as a result of underlying heart disease.  They often occur in young adults with no symptoms. 

In your situation, many questions need answering.  These include: age; risk factors for heart disease (elevated lipid levels, smoking, excessive weight, diabetes, high blood pressure, family history of heart disease, previous heart problems), any symptoms that might indicate heart problems; and, other possible underlying diseases. 

After a thorough history and physical examination, your physician will be in the best position to decide whether further evaluation is warranted.  So, I reccommend you make an appointment (if not done yet) to see your doctor and get his/her input to what steps might be necessary.  These steps could include an echocardiogram (sound wave picture of the heart and its structures), stress testing, blood work, or simple observation. 

Best wishes.  I hope this information has been useful to you.

Martin Cane, M.D.