left bundle branch block (LBBB)

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Introduction

An ECG change characterized by an intraventricular conduction delay affecting the left ventricular wall & septum. Acute occurrences most commonly result from myocardial ischemia.

Etiology

* Incidentally found left bundle branch block (LBBB) with normal left ventricular ejection fraction is associated with increased cardiac morbidity & mortality.[2]

Diagnostic procedures

cardiac stress testing

* Cannot identify LVH or RVH in the presence of LBBB

More general terms

References

  1. Practical ECG Interpretation, T Evans, Ring Mountain Press, 1998
  2. Jump up to: 2.0 2.1 Miller WL, Ballman KV, Hodge DO, Rodeheffer RJ, Hammill SC. Risk factor implications of incidentally discovered uncomplicated bundle branch block. Mayo Clin Proc. 2005 Dec;80(12):1585-90. PMID: https://www.ncbi.nlm.nih.gov/pubmed/16342651
  3. Jump up to: 3.0 3.1 Medical Knowledge Self Assessment Program (MKSAP) 16. American College of Physicians, Philadelphia 2012
  4. Jump up to: 4.0 4.1 4.2 NEJM Knowledge+
    Sgarbossa EB. Recent advances in the electrocardiographic diagnosis of myocardial infarction: left bundle branch block and pacing. Pacing Clin Electrophysiol. 1996 Sep;19(9):1370-9. PMID: https://www.ncbi.nlm.nih.gov/pubmed/8880802 Review.
    Meyers HP, Limkakeng AT Jr, Jaffa EJ et al Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: A retrospective case-control study. Am Heart J. 2015 Dec;170(6):1255-64. PMID: https://www.ncbi.nlm.nih.gov/pubmed/26678648