<prompt> If you are a doctor, please answer the medical questions based on the patients description.My son is 8 years old with a diagnosis of autism. He visited a family physician and they said is heart rate was low and ordered an ekg and it showed right bundle branch block. What does this mean? Was he born with it? He is going to see a cardiologist in maryland tomorrow.  <response>: A right bundle branch block RBBB is a heart block in the electrical conduction system. During a right bundle branch block, the right ventricle is not directly activated by impulses travelling through the right bundle branch. The left ventricle however, is still normally activated by the left bundle branch. Its normal in 85 of people however in an 8 years old kid 2d echo should be done to rule out possibility of ASDatrial septal defect, yes I can be by birth also, it can be because of autism also. 