Key result
Alternating bundle branch block with 2:1 AV block signals high risk of complete AV block.
Why the study?
The mechanism underlying QRS alternans with narrow QRS complex and bundle branch block in the setting of 2:1 AV block was unclear.
Case Report (n=1)
May warrant closer ECG surveillance in conduction disease; leaves open prospective validation of dual bundle branch block risk.
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.
No takes yet. Share an insight, caveat, or question.
Yamada et al. (2008) conducted a case report in Symptomatic bradycardia with QRS alternans and 2:1 AV block (n=1). QRS alternans with narrow QRS complex and bundle branch block with 2:1 AV block was evaluated on Complete AV block. 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.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: