I am looking at a picture in my book for the placement of electrodes for a 12 lead ekg and it only shows 10 leads! But it specifically says 12 lead ecg, which I always assumed meant 12 electrodes. There is 1 on each wrist, 1 on each ankle, 5 on the left side of the chest, and 1 on the right side of the chest. It only adds up to 10, where do the other 2 leads go? Thank you
Mar 9, '14
Google composite leads
Remember you have three limb leads, three composite leads, and six precordial leads.
It's not the number of electrodes, it's the polarity of the electrodes.
Mar 10, '14
Look at a print out of a 12 lead: Leads I, II, III, aVL, aVF, aVR, plus V1 - V6. That adds up to 12.
Mar 10, '14
The three "augmented" leads are "generated" by using the existing leads. There are additional electrodes that go on the body for those leads. Using a standard 3 lead monitor, I can approximate 9 of the 12 leads. As long as you put the electrodes and leads (wires) in the right places, the machine can electrically "create" those three other leads. I've heard of EKG technology that can generate multiple leads from 5 precisely placed electrodes... Such technology is likely expensive and may not yet be on the market in any large numbers. but it's very cool stuff because you can "see" any lead you desire.
It's OK to wonder about such things. I did at first until it was explained to me about how the machine works to create the augmented leads.
Mar 11, '14
There are only 10 "wires" to be connected. The 12 lead is on paper looking at different "view" or axis of the heart.
Mar 21, '14
This site can explain pretty much any question you have about 12L ECG
ECG Library and clinical cases in cardiology