Is IRBBB dangerous?
Patient: my 11 yr old son was told he has IRBBB. Naturally as parents we are so stressed. He is VERY athletic and loves sports. Sometimes gets a little short of breath with endurance sports like Basketball.. we have a dr's appt next week. Hopefully will get news... but how serious is IRBBB? Doctor: Thanks for your question on Health Care Magic. I can understand your concern. IRBBB is Incomplete Right Bundle Branch Block. First of all, you need to understand basis of bundle branch to understand IRBBB. There are two bundle branches in heart which transmit the impulse from atria to ventricle. Right and left. Any block in this transmission, can cause problem in transmission of impulse from atria to ventricle and hence ventricle will not function properly. In pediatric patient, most common cause for this is developmental defect. So in your son's case, his right bundle branch is blocked incompletely. So right ventricle is not functioning well. Right ventricle is connected to lungs, so he feels shortness of breath on exertion. Honestly speaking, this is serious health issue and this can worsen with the age. So consult cardiologist as soon as possible for this  IRBBB. Hope I have solved your query. I will be happy to help you further. Wishing good health to your son. Thanks.