Cardiology Teaching Package
A Beginners Guide to Normal Heart Function, Sinus Rhythm & Common Cardiac Arrhythmias
Bipolar Leads
Well, the 2 leads situated on the right and left wrist (or shoulders), AVr and AVL respectively, and the lead situated on the left ankle (or left lower abdomen) AVf, make up a triangle, known as "Einthoven’s Triangle". Information gathered between these leads is known as "bipolar". It is represented on the ECG as 3 "bipolar" leads. So,
- information between AVr and AVl is known as lead l.
- Information between AVr and AVf is known as lead ll
- Information between AVl and AVf is known as lead lll
Image: Einthoven’s triangle - Line of site of the bipolar leads
Now we have 12 leads, we need to know which regions of the heart each lead is looking at and what groups they make up.
Regions of the Heart
- AVL is on the left wrist or shoulder and looks at the upper left side of the heart.
- Lead l travels towards AVL creating a second high lateral lead.
- AVf is on the left ankle or left lower abdomen and looks at the bottom, or inferior wall, of the heart.
- Lead ll travels from AVr towards AVf to become a 2nd inferior lead
- Lead lll travels from AVL towards AVf to become a 3rd inferior lead.
- V2 V3 and V4 look at the front of the heart and are the anterior leads.
- V1 is often ignored but if changes occur in V! and V2 only, these leads are referred to as Septal leads.
- V5 and V6 look at the left side of the heart and are the lateral leads.
The ECG below shows where these leads are when printed.
Image: ECG with regions of the heart highlighted
This diagram is avaible at full size as a Adobe PDF for you to download
- Download PDF version of the ECG diagram highlighting regions of the heart
Adobe PDF - 646 KB - opens in a new window - To enable you to view the Adobe Acrobat PDF you will require Adobe Acrobat Reader available for free here
