Hi @rogue_doctor, Your question: "is it possible for the left ventricle to cause a RBBB and not the right ventricle?" appears to remain unanswered by the experts according to your research. Mayo Clinic Connect is an online community of patients, sharing support, experiences and information. It will be interesting to see if anyone has anecdotal evidence of the left ventricle causing RBBB to support your hypothesis. Do you have right bundle branch block (RBBB)?