Question: why is lbbb worse than rbbb?
Answer: In a chronic cardiomyopathy cohort, RBBB is associated with ischemic cardiomyopathy and large anteroseptal scar, while LBBB is associated with nonischemic etiologies. The large myocardial scar in RBBB patients may explain why they have even worse mortality than non-specific LV conduction delay patients receiving CRT.