The Full Form of RBBB is Right bundle branch block.

Right bundle branch block (RBBB) is an electrocardiogram finding that occurs when the physiologic electrical conduction system of the heart, specifically in the His-Purkinje system, is altered or interrupted resulting in a widened QRS and electrocardiographic vector changes. The bundle of His divides in the interventricular septum into the right and left bundle branches. Initially, the right bundle branch off of the bundle of His travels down the interventricular septum near the endocardium. It then dives deeper into the muscular layer before re-emerging near the endocardium again. The right bundle branch receives most of its blood supply from the anterior descending coronary artery. It also receives collateral circulation from the right or left circumflex coronary arteries, depending on the dominance of the heart.

Right bundle branch block is associated with structural changes from stretch or ischemia to the myocardium.It can also occur iatrogenically from certain common cardiac procedures, such as right heart catheterization. Although there is no significant association with cardiovascular risk factors, the presence of a right bundle branch block is a predictor of mortality in myocardial infarction, heart failure, and certain heart blocks. In asymptomatic patients, isolated right bundle branch block typically does not need further evaluation.