This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Left anterior fascicular block (LAFB)

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

This occurs if there is a failure of conduction of either the anterior or posterior fascicle of the left bundle. If there are no other conduction abnormalities then the duration of the QRS complex is not prolonged beyond 0.11s.

  • if there is left anterior fascicle block then this results in left axis deviation.
  • if there is left posterior fascicle block then this is associated with right axis deviation.

Click here for an example ECG of left anterior fascicular block

Click here for an example ECG of left posterior fascicular block

Related pages

Create an account to add page annotations

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.