Battle of the Best 12 Lead ECG Placement!

[Angel Barrientos]

What are the Pros and Cons of placing the RA and LA leads on the forearm vs. placing the same leads right on the deltoids? As an EMT, I was always told to place the leads on the forearms or wrist by the Firefighter paramedics, but some of my clinical instructors have said that is wrong or that it provides a less accurate reading. Is this true? What is the best 12- lead placement? Links to research articles or resources will be much appreciated. Thank you for your time!

 

[CWATT]

Interesting question. Here are a few quick thoughts:

- If the limb leads are placed on the peripheries of someone who is restless (hypoxia, pain, age, drugs/alcohol, etc.), then you’re going to get a lot more artifact.

- Limb leads placed on the peripheries may also create a spaghetti mess — obstructive to other EMS personnel, patient access, and IV lines.

- There may however be contraindications to placing limb leads on the core (local trauma, bleeding, etc.)

- Since the ECG monitor uses a computer algorhythm to calculate the limb leads, I’m not aware of any conductance reasons to place them in one location over another.

 

[Aprz]

In my opinion, and maybe I am being ignorant here, but the difference are insignificant. When you place the leads on the trunk, it will move the mean vector QRS a little more rightward I think. Most people can't even figure out axis, so I don't know why they are tripping. It should not create or hide ST changes, which is what we care about; It might create q waves which are usually "old" MIs. For the green/RL lead, you can put that anywhere, even on the forehead, and the ECG won't change. You can put the red/LL lead on the right leg instead, and the ECG will come out the same. In my own opinion, you don't even need to be precise with the precordial leads. Just get the general spot. We always talk about being precise with those, yet we often put lead V1 and V2 way too high making a pseudo RBBB pattern, which ECG enthusiast will recognize anyways. I think this whole "limb leads go on limbs" and stuff is like a cultural thing where we get tough about things that we don't really need to be tough on.

 

[DrParasite]

well, they are called limb leads for a reason....

 

[VentMonkey]

well, they are called limb leads for a reason....

In short, this. My initial paramedic instructors were proponents of torso placement, my CCP instructor not so much. Proper placement, much like proper precordial lead placement, is important.

Maybe the question to ask yourself would be—does it make a big enough difference everytime to, alone, make up my clinical course and decisions for the patient in front of me?

Practicality and reality sometimes intertwine, and the placement alone may not be enough to override the ol’ “gut feeling”.

 

[truetiger]

They're called limb leads for a reason.....putting them on the torso can alter things such as axis.

 

[mgr22]

I Googled research on this. Placing limb leads on limbs, instead of on torsos, seems to be more important than where they're placed on those limbs.

 

[Gurby]

I Googled research on this. Placing limb leads on limbs, instead of on torsos, seems to be more important than where they're placed on those limbs.

Does that mean deltoids is pretty much fine?

 

[mgr22]

Does that mean deltoids is pretty much fine?

The article I found did not evaluate different locations on limbs. Also, the study focused on placement of upper limb leads. To summarize, it was a study comparing placement of LA and RA on arms vs. torsos. The conclusion was that the latter caused some distortion in EKGs.

 

[NPO]

I was taught that as long as the leads are in their correct positions relative to the heart, then it's fine.

However, my employer really prefers leads be placed on the limbs, especially if a 12-lead is being done. I have placed leads on the chest and abdomen for most of my life, but recently switched because of this preference by my employer (and most of my EMTs place them like this anyway).

However, when some patients are too restless to get an accurate look at even lead II, or can't keep the leads on because they're moving too much, I'll move them to more central locations.

Being able to keep the monitor on, and identify the correct underlying rhythm is more important for monitoring purposes than the small changes in axis that may or may not exist with torso placement*.

* I'll make an exception for diagnostic EKGs and printouts. Axis can be more important here.

 

[NPO]

Because I don't much like "hearsay" answers like the one I gave, I decided to collect some data. I just completed a study of healthy 25 year old paramedics with a sample size of 1.

These were taken with a LP15, with me laying on the gurney at a 30ish degree angle. The first is with the leads on my torso, the second on my limbs.

My interpretation is this;
- There is noticable axis change, but it doesn't change the axis quadrants.
- The axis in the torso EKG looks "more correct" to me, but neither is outside the normal variant.
- The most notable change is in Lead III, where it goes from positive in the torso ekg to equiphasic in the limb ekg.
- There is more artifact in the limb ekg, which required 3 EKGs to get a clean one, compared to one with the torso placement.

 

[dumbenoughtostay]

As always, there are plenty of opinions on this topic. Perhaps we could consider an answer from the experts. Please note these points (copied and pasted) from http://circ.ahajournals.org/content/115/10/1306:

1. For routine 12-lead recording, the AHA statement of 1975 recommended placement of the 4 limb lead electrodes on the arms and legs distal to the shoulders and hips, and thus not necessarily on the wrists and ankles. Evidence exists that different placement of electrodes on the limbs can alter the ECG, a phenomenon that appears to be more marked with respect to the left arm electrode.
   
2. Six electrodes are placed on the chest in the following locations: V1, fourth intercostal space at the right sternal border; V2, fourth intercostal space at the left sternal border; V3, midway between V2 and V4; V4, fifth intercostal space in the midclavicular line; V5, in the horizontal plane of V4 at the anterior axillary line, or if the anterior axillary line is ambiguous, midway between V4 and V6; and V6, in the horizontal plane of V4 at the midaxillary line.
   
3. Clinical Implications
   Skin preparation and electrode placement have important effects on the ECG, and patient positional change, such as elevation and rotation, can change recorded amplitudes and axes. It has been widely accepted for many years that ECG amplitudes, durations, and axes are independent of the distal or more proximal location of the limb electrodes. As a result, routine recording of the ECG from the upper arm rather than from the wrist to “reduce motion artifact” has become popular and is facilitated by the development of disposable tab electrodes. However, one study has shown that electrode placement along the limbs can affect ECG voltages and durations, most importantly in the limb leads.81 Whether these differences are large enough to alter routine diagnostic criteria, such as voltage for left ventricular hypertrophy or Q-wave duration for inferior infarction, is unknown.
   

Further reading in the article demonstrates common placement errors for the pre-cordial leads and the resulting problems.

To me the bottom line is we should closely follow the standards set out by expert authorities. Lead placement can make a difference.

Side note: I seem to recall a study that showed that of all those tasked with obtaining 12 lead ECGs, cardiologists were the most likely to place the leads incorrectly!

 

[MSDeltaFlt]

If you're going to just monitor then the torso is fine. However, if you are going to assess a 12 lead ECG, then left arm means LEFT FREAKING ARM!!!

 

[FiremanMike]

If you're going to just monitor then the torso is fine. However, if you are going to assess a 12 lead ECG, then left arm means LEFT FREAKING ARM!!!

<shrug> Zoll recommends limb leads go at least 10cm from the heart, but state torso limb lead placement is fine.

 

[Tigger]

I am happy I know how to discern axis. Knowledge is good. But really, axis alone should not be something you hang any decision off. The two times I hear it bandied about are for discerning respiratory or cardiac strain patterns (COPD vs. CHF) and differentiating V-Tach from aberrantly conducted SVT. Axis is specific to neither of those things, at all.

If I have to move the limb leads to the torso to get an actually readable EKG, that seems reasonable. Sometimes it's cold in Colorado and people shiver.

 

[jwk]

If you're going to just monitor then the torso is fine. However, if you are going to assess a 12 lead ECG, then left arm means LEFT FREAKING ARM!!!

It really doesn't. Really.

I used to do EKG's in the dark ages where we put conductive gel under a metal plate secured to the patient's limbs with a rubber strap. That's where "limb leads" started. There was no such thing as self-adhesive EKG pads, much less something like a defib pad.

As long as you're placing the leads in the proper orientation across the heart, leads on the shoulders are just as good as leads on the wrist or forearm or upper arm - or ankles, shins, or thighs. As Aprz pointed out, the green RL lead can go anywhere on the body and it makes no difference at all. Every EKG I've seen in the last 25 years, including all my surgery patients and including our very busy ER and cath labs, use torso leads. Your V-leads are the only ones that need to have much more specificity with regards to placement.