QRS alternans with 2:1 atrioventricular conduction block: What is the mechanism?

Academic Article


  • An 81-year-old woman was admitted for symptomatic bradycardia. On admission, the ECG exhibited QRS alternans, narrow QRS complex and left bundle branch block with 2:1 AV block. The patient soon had complete AV block and underwent a pacemaker implantation. An appropriate mechanism for explaining those ECG findings might be 4:1 conduction over the left bundle branch and 2:1 conduction over the right bundle branch. An ECG pattern exhibiting QRS alternans with a narrow QRS complex and bundle branch block with 2:1 AV block may suggest the coexistence of both bundle branch blocks and a high risk of complete AV block. © 2008, Copyright the Authors.
  • Digital Object Identifier (doi)

    Pubmed Id

  • 16474398
  • Author List

  • Yamada T; Tabereaux PB; McElderry HT; Kay GN
  • Start Page

  • 314
  • End Page

  • 316
  • Volume

  • 13
  • Issue

  • 3