Atrioventricular Blocks (AVBs): the types and how to differentiate them

MD Tobias Araujo, specialized in Cardiology and Medicine Intensive

AHA Instructor (BLS, ACLS and PALS)

Today we will show you a video made by Dr Tobias Araujo, in which he brings us the AVBs in a simple and easy to understand way.

Link for watching the video above on our YouTube channel:

https://www.youtube.com/watch?v=_8M8KPaZAXk&t=108s

Atrioventricular blocks, also called Heart Blocks, are cardiac arrhythmias, usually with low heart rate (Bradyarrhythmias), in which there is a delay or interruption in the transmission of the electrical impulses from the atria to the ventricles.

There is some damage to the cardiac electrical conduction system in one or more structures from the atrioventricular node (AV node) to the purkinje fibers (AV node -> Bundle of His -> Bundle Branches -> Purkinje Fibers), interrupting the flow of the electrical impulses to the ventricular mass, where they are able to trigger ventricular contraction.

Depending on the level and intensity of damage to the cardiac electrical conduction system mentioned above, there can be different types of AVBs: First degree AVB; Second degree AVB, divided into Mobitz type I and Mobitz type II; and Third degree AVB (or total AVB).

Analyzing the PR interval (measurement from the beginning of the P wave to the beginning of the QRS complex) and the type of relationship between the Ps waves and the QRSs, in addition to the width of the QRS complex, we can define the type of Heart Block and thus we can give the best treatment for our patient.

Check out the video above and find out more about the types of AVBs and how to tell them apart.