Overview

In this course we teach you how to identify first-, second- and third-degree atrioventricular (AV) block on the ECG. We explain the pitfalls commonly encountered in the diagnosis of AV block. You will learn the importance of distinguishing between Mobitz type I and Mobitz type II second degree AV block and you will learn how to do so reliably.

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:

• Diagnose first, second and third-degree atrioventricular (AV) block on the ECG
• Discriminate between Mobitz type I and Mobitz type II second degree AV block on the ECG
• Identify high grade and untypable AV block on the ECG
• Distinguish between non-conducted premature atrial contractions and AV block on the ECG

Course Content

• Introduction
• First Degree AV Block
• Second Degree AV Block
• Pitfalls in Second Degree AV Block
• Third Degree AV Block
• Quiz
• Essential Reading

Release date

30-JUL-2023

Expiration date

30-JUL-2026

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. Read the papers on the essential reading list
3. Complete the quiz
4. Complete the activity evaluation form to provide feedback for continuing education purposes and for the development of future activities
5. Download the Certificate of Completion

Relevant Financial Disclosures

Acadoodle adheres to the ACCME's Standards for Integrity and Independence in Accredited Continuing Education. Any individuals in a position to control the content of a CE activity, including faculty, planners, reviewers or others are required to disclose all relevant financial relationships with ineligible entities (commercial interests). All relevant conflicts of interest have been mitigated prior to the commencement of the activity.

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

Bibliography

Garcia T and Miller G. (2004) Arrhythmia Recognition: The Art of Interpretation. 1st Edition. Chapter 35: Atrioventricular Block. Jones & Bartlett Learning. 

Barold SS and Hayes DL. Second-degree Atrioventricular Block: A Reappraisal. Mayo Clin Proc. 2001;76:44-57. https://www.mayoclinicproceedings.org/article/S0025-6196(11)62080-6/pdf

Barold SS. Case Report: Type I Second-Degree AV Block Masquerading as Type II Block. J Interv Electrophysiol. 2000;4:599-603. https://link.springer.com/content/pdf/10.1023/A:1026520507634.pdf

Barold SS and Herweg B. Second-Degree AV Block Revisited. Herzschrittmacherther Elecktrophysiol. 2012;23:296-304.
https://link.springer.com/article/10.1007%2Fs00399-012-0240-8

Malik M & Camm AJ. Mechanism of Wenckebach Periods: Hypothesis based on Computer Modelling. Am J Physiol. 1989;257(4):H1263-H1274.
https://journals.physiology.org/doi/abs/10.1152/ajpheart.1989.257.4.H1263

Hansom SP et al. The Wenckebach Phenomenon. Curr Cardiol Rev. 2021;17(1):10-16.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8142363/

Barold SS et al. Reappraisal of the Traditional Wenckebach Phenomenon with a Modified Ladder Diagram. Ann Noninvasive Electrocardiol. 2012;17(1):3-7.
https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1542-474X.2011.00474.x

Barold SS. Type I Wenckebach second-degree AV block: A matter of definition. Clin Cardiol. 2018;41(3):282-4.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6489887/

Additional Reading

Sidhu S & Marine JE. Evaluating and Managing Bradycardia. Trends Cardiovasc Med. 2020;30:265-72.
https://www.sciencedirect.com/science/article/pii/S1050173819300933?via%3Dihub

Paper contains informative high-resolution images with examples of ECG findings in various forms of bradycardia and AV node dysfunction. Make sure you can identify the abnormalities illustrated in these figures. Also, the authors discuss the 2018 ACC/AHA/guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay

The Wenckebach Phenomenon

Barold SS et al. Reappraisal of the Traditional Wenckebach Phenomenon with a Modified Ladder Diagram. Ann Noninvasive Electrocardiol. 2012;17(1):3-7.
https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1542-474X.2011.00474.x

Mond H. Sino-atrial Wenckebach. Cardioscan. July 2020.
https://uk.cardioscan.co/blog/resource/sino-atrial-wenckebach/

Schamroth L & Dove E. The Wenckebach Phenomenon in sino-atrial block. Br Heart J. 1966;28(3):350-8.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC487880/

Burns E & Buttner R. AV Block: 2nd Degree, Mobitz I, Wenckebach Phenomenon. Life in the fastlane. 2021.
https://litfl.com/av-block-2nd-degree-mobitz-i-wenckebach-phenomenon/

Illustrative Case Reports in Atrioventricular Block

The free access papers below include informative examples of the ECG findings associated with atrioventricular block.

Ergle K et al. High-Grade Atrioventricular Block Associated with Acute Influenza. Tex Heart Inst J. 2020;47(3):220-3.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7529078/

Figure 1 (A) Third-degree AV block with a narrow-complex escape rhythm. (B) Second degree AV block (un-typable).

Roguero-Sopena M et al. Transient type I 2nd-degree congenital atrioventricular block: a case report. Arch Cardiol Mex. 2023;93(1);124-6.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10161836/

Nice example of Type I second degree AV block

Francisco JI et al. Sudden cardiac arrest due to atrioventricular block: A diagnostic challenge. Rev Port Cardiol. 2018;37(11):e1-947.e4.
https://www.sciencedirect.com/science/article/pii/S0870255117300252?via%3Dihub

Figure 1B is of particular interest. Map out the expected sites of P waves and learn how to recognise fusion complexes. The fusion complexes occur in a repetitive pattern on this strip. Atrial and ventricular depolarization are independent of one another but both are occurring at a regular fixed rate producing a recurring pattern of distortion of the ST segment (every third qrs complex).

Nakashima T et al. A 2:1 atrioventricular block presenting paradoxical ventriculophasic response. Ann Noninvasive Electrocardiol. 2019;24:e12642.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6931805/pdf/ANEC-24-e12642.pdf

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.