Cardiac Conduction: Bundle Branch Block

The ability to identify a bundle branch block pattern on the ECG, and to assess its clinical relevance, is a key skill in general medicine. In this course, we will teach you how to distinguish between complete right bundle branch block and complete left bundle branch block on the ECG. You will also learn how to identify ECG patterns believed to reflect damage to multiple components of the cardiac conducting system.

2.0 x AMA PRA Category 1 Credits™
Available on the Pro Plan

PLAY INTRODUCTION

Overview

The ability to identify a bundle branch block pattern on the ECG, and to assess its clinical relevance, is a key skill in general medicine. In this course, we will teach you how to distinguish between complete right bundle branch block and complete left bundle branch block on the ECG. We will show you the abnormal events in the heart which are thought to produce the predictable ECG changes associated with both of these entities. We teach you how to identify right- and left-incomplete bundle branch block on the ECG. You will also learn how to identify ECG patterns believed to reflect damage to multiple components of the cardiac conducting system; bifascicular and trifascicular block. We will teach you how to identify the likely site of origin, within the ventricles, of a premature ventricular contraction.

Faculty

Planner and Author: Dr John Seery MB PhD

  • Consultant Physician at St. Vincent's University Hospital, Dublin, Ireland
  • Lecturer at the School of Medicine and Medical Science, University College Dublin, Ireland
  • Studied medicine at the University of Cambridge, United Kingdom
  • A Natural Sciences graduate of Trinity College Dublin, Ireland
  • PhD in Cell Biology from University College London, United Kingdom


Planner: Dr Karen Strahan PhD (University of Cambridge), Head of Editorial
Planner: Tommy O'Sullivan, CME Manager
 

Estimated Time to Complete

2.0 hours

Target Audience

  • Physicians
  • Nurses
  • Nurse Practitioners
  • Physician Assistants
  • Paramedics

Learning Objectives

Upon successful completion of this activity, you will be able to:

  • Explain the qrs morphological changes of complete left bundle branch block and complete right bundle branch block
  • Identify the anatomical site of origin of premature ventricular contractions based on analysis of qrs morphology
  • Explain aberrant conduction occurring in response to changes in heart rate
  • Distinguish between complete left and complete right bundle branch block on the ECG 
  • Identify incomplete left and incomplete right bundle branch block on the ECG
  • Identify bifascicular and trifascicular block on the ECG
  • Identify rate dependent aberrancy on the ECG

Course Content

  • Introduction
  • The Transverse Schematic
  • Complete Right Bundle Branch Block
  • Complete Left Bundle Branch Block
  • The Diagnosis of Bundle Branch Block
  • Incomplete Bundle Branch Block
  • Episodic Aberrancy
  • Combined Conduction Abnormalities
  • Site of Origin of PVCs
  • Quiz
  • Essential Reading

Release date

30-JUL-2020

Expiration date

29-JUL-2023

Instructions for Participation

Participants must complete the online activity during the valid period as noted above.
Follow these steps:

  1. View videos in sequence
  2. Complete quiz
  3. Complete the activity evaluation form to provide feedback for continuing education purposes and for the development of future activities
  4. Download the Certificate of Completion

Relevant Financial Disclosures

Planners and faculty for this activity have no relevant financial relationships with commercial interests to disclose.

Bibliography


Surawicz B et al. AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram Part III: Intraventricular Conduction Disturbances. Circulation. 2009;119:e235-e240.
https://www.ahajournals.org/doi/pdf/10.1161/CIRCULATIONAHA.108.191095

Surkova E et al. Left bundle branch block: from cardiac mechanics to clinical and diagnostic challenges. EP Europace. 2017;19(8):1251-71.
https://academic.oup.com/europace/article/19/8/1251/3746065

Schamroth L and Bradlow BA. Incomplete left bundle-branch block. Br Heart Journal. 1964;26:285-8.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1018120/pdf/brheartj00343-0129.pdf

Bussink BE et al. Right bundle branch block: prevalence, risk factors, and outcome in the general population: results from the Copenhagen city heart study. Eur Heart J. 2013;34(2):138-46. 
https://academic.oup.com/eurheartj/article/34/2/138/433900

Fernandez-Lozano I and Brugada J. Right bundle branch block: are we looking in the right direction? Eur Heart J. 2013;34:86–8.
https://academic.oup.com/eurheartj/article/34/2/86/434788

Fisch C et al. Rate Dependent Aberrancy. Circulation 1973;58:714-24.
https://www.ahajournals.org/doi/pdf/10.1161/01.CIR.48.4.714

Additional Reading

Hollman A. The history of bundle branch block. Med Hist Suppl. 1985;(5):82-102. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2557404/
Wilner B et al. LBBB in patients with suspected MI: an evolving paradigm. Am Col Cardiol. Latest in Cardiol. 2017
https://www.acc.org/latest-in-cardiology/articles/2017/02/28/14/10/lbbb-in-patients-with-suspected-mi

Almeida ND et al. Cardiac Resynchronization Therapy in Heart Failure: Do Evidence-Based Guidelines Follow the Evidence? Circulation. 2017;10
https://www.ahajournals.org/doi/10.1161/CIRCOUTCOMES.117.003554

Shetty RK et al. Trifascicular block progressing to complete AV block on exercise: a rare presentation demonstrating the usefulness of exercise testing. BMJ Case Rep. 2015; bcr2014209180. doi:10.1136/bcr-2014- 209180.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4386303/pdf/bcr-2014-209180.pdf

Leighton R et al. Incomplete Left Bundle-Branch-Block: The View from Transseptal Intraventricular Leads. Circulation. 1967;36:261-74.
https://www.ahajournals.org/doi/pdf/10.1161/01.CIR.36.2.261

Fukuda K et al. Histopathological Study on the Conduction System of Complete Right Bundle Branch Block with Special References to Configuration of QRS Complex. Jap Heart J. 1979;20(6):83-44.
https://www.jstage.jst.go.jp/article/ihj1960/20/6/20_6_831/_pdf

Tomita M et al. A complete right bundle-branch block masking Brugada syndrome: a case. J Electrocardiol. 2012;45(6):780-2.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3483429/

ACCME Accreditation Statement

Acadoodle, Ltd is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

Credit Designation Statement

AMA Physician’s Recognition Award

Acadoodle, Ltd designates this enduring material activity for a maximum of 2.0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

 
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