World Library  
Flag as Inappropriate
Email this Article

Trifascicular block

Article Id: WHEBN0000666831
Reproduction Date:

Title: Trifascicular block  
Author: World Heritage Encyclopedia
Language: English
Subject: First-degree atrioventricular block, Bundle branch block, Bundle of His, HACEK endocarditis, Right atrial enlargement
Collection: Cardiac Dysrhythmia
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Trifascicular block

Trifascicular heart block
Classification and external resources
ICD-10 I45.3
ICD-9-CM 426.54

Trifascicular block is a problem with the electrical conduction of the heart. It is diagnosed on an electrocardiogram (ECG/EKG) and has three features:[1]

Contents

  • Differential diagnosis 1
  • Diagnosis 2
  • Treatment 3
  • References 4
  • External links 5
  • See also 6

Differential diagnosis

Trifascicular block is important to diagnose because it is difficult to tell based on the surface ECG whether the prolonged PR interval is due to disease in the AV node or due to diffuse distal conduction system disease.

  • In the former case, if the block at the AV node level becomes complete, the escape rhythm will originate from the bundle of His, which typically will generate heart rates in the 40s, allowing the individual to survive and complain of symptoms of fatigue or near-syncope to their physician.
  • In the latter case, however, because the conduction system disease is diffuse in nature, the escape rhythm may be fascicular or ventricular, which may be at rates that are life-threateningly low.

Diagnosis

The diagnosis of whether the PR prolongation is due to AV nodal disease or diffuse conduction system disease is typically made by an electrophysiology study of the conduction system. In an electrophysiology study, trifascicular block due to AV nodal disease (true trifascicular block does not involve the AV node) block is represented by a prolonged AH interval (denoting prolonged time from impulse generation in the atria and conduction to the bundle of His) with a relatively preserved HV interval (denoting normal conduction from the bundle of His to the ventricles). Trifascicular block due to distal conduction system disease is represented by a normal AH interval and a prolonged HV interval.

Treatment

The treatment for diffuse distal conduction system disease is insertion of a pacemaker. If the PR prolongation is due to AV nodal disease, a case may be made for observation, as it may never progress to complete heart block with life threateningly low heart rates.

Regardless of where in the conduction system the block is, if the block is believed to be the cause of syncope in an individual, a pacemaker is an appropriate treatment.

References

  1. ^ 1161101334 at GPnotebook

External links

  • http://library.med.utah.edu/kw/ecg/mml/ecg_0293_mod.html
  • http://www.ecglibrary.com/trifas.html

See also

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.