Levt Bundle Branch blocking

I've had Right Bundle Branch Block for years and it has posed no problems for me.  However, since 2005
I've developed Left Bundle Branch Block.  (I'm 78 so I should be developing something I guess). LBBB is more problematical since it obscures diagnosis of more serious problems due to its behavior on the EKG.

So the question is what tests, lab or otherwise, are effective in determining the cause of LBBB.

I've had a stress test and echocardiograph  and they came out clean although showing the LBBB.

Appreciate any thoughts,

Hugheen

[CCF HeartMD6]

Are you certain that you have both a left and a right bundle branch block? This would seem to indicate that you have complete heart block (i.e. blocking of both bundles below the AV node). BBB can be a result of numerous causes including ischemia, medications, infiltrative disorders, or aging of the conduction system (i.e. fibrosis). The causes of BBB may never be elucidated, although a careful history and physical may give clues as to the reason (if any). Echocardiograms can also be of utility to evaluate the other anatomical structures of the heart.