Bilateral Bundle Branch Block

Card Electrophysiol Clin. 2021 Dec;13(4):685-689. doi: 10.1016/j.ccep.2021.06.008. Epub 2021 Sep 23.


Left bundle branch block (LBBB) and right bundle branch block (RBBB) are classic manifestations of bundle branch conduction disorders. However, a third form that is uncommon and underrecognized may exist that has features and pathophysiology of both: bilateral bundle branch block (BBBB). This unusual form of bundle branch block exhibits an RBBB pattern in lead V1 (terminal R wave) and an LBBB pattern in leads I and aVL (absence of S wave). This unique conduction disorder may confer an increased risk of adverse cardiovascular events. BBBB patients may be a subset of patients that respond well to cardiac resynchronization therapy.

Keywords: Bilateral bundle branch block; Bundle branch block; Conduction system disorder; Left bundle branch block; Right bundle branch block.

Publication types

  • Review

MeSH terms

  • Bundle-Branch Block* / therapy
  • Cardiac Conduction System Disease
  • Cardiac Resynchronization Therapy*
  • Electrocardiography
  • Heart Conduction System
  • Humans