Cardiac conduction system disorders on the electrocardiogram (ECG) are common. Left bundle branch block (LBBB) is associated with adverse outcomes, and variants previously considered normal, such as right bundle branch block (RBBB),1 left anterior fascicular block,2 or PR interval prolongation,3 may also portend morbidity and mortality.
Narayan SM, Baykaner T, Maron DJ. Can Cardiac Conduction System Disease Be Prevented?. JAMA Intern Med. 2016;176(8):1093-1094. doi:10.1001/jamainternmed.2016.2863