I also have an incomplete RBBB, I have also undergone a couple of echos and nuclear stress tests and have been told the IRBBB is of no consequence and is not symptomatic. These rarely have any significance, especially in an otherwise healthy heart, unlike a left bundle branch block which is more indicative of pre-existing heart disease.
Good Luck,
Jon
An ECG is not a very good, reliable source and requires more clinical evidence, symptoms, etc. for a diagonosis. The source of the problem can be a deficiency of electrolytes in the system, diet, etc. or there can be a structural change to the tissue from its natural state
The right bundle branch is the conductive pathway for electrical impules to directly activate the right heart chamber (pump blood to the lungs). There should be no effect on the left side activity.
To answer your question requires confirmation with other evidence, symptoms, and whether or not it is serious requries an assessment by your doctor. Worst case scenario would require a pacemaker.