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How to read atrial ECG?

Cardiac   (1,652 Views 4 Comments)
by nurs1ng nurs1ng (Member) Member

6,337 Profile Views; 149 Posts

How the heck do you read an atrial ECG? I know that doing this augments the atrial wave on ECG but how do you interpret the reading itself? Yes, I'm aware of comparing the atrial ECG with the normal ECG (with strips printed side by side on the same paper). But I'm just not understanding what I'm looking for.. do I just look for AV dyssynchrony? Whether it's really a fib, flutter or junctional? Which lead is preferable in connecting the atrial wire to (specifically, where do I hook up the negative and the positive)? Pretty lost at this. Any direction/guide would really help. Thanks!

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29 Posts; 538 Profile Views

Ok.. I actually registered here.. Explicitly because i saw this and am completely lost lol...

What exactly are you asking for? Atrial ecg? This is an entirely new term for me...

Im familiar with surface ecg interpretation, saecg interpretation... Even intracardiac egm interpretation.. I can interpret 3d mapping data..

But bruh if theres like.. Some sort of hookup technique or method or technology to take a better look at atrial depolarization non invasively my mind will be blown..

If on the other hand your just asking for generic ecg advise for looking at p waves thats an easier one.. If there is actually an atrial ecg.. Ignore the following.

Yeah look at your basic rhythm.. Sure.. Look at p wave regularity and consistent morphology to rule out wap, and ensure you have a p wave for each qrs and that the pattern makes sense. Inverted p waves could mean junctional.. But dont forget the big picture.. Confirm findings of inverted p waves across numerous leads to rule out lead displacement. Check your pr segment to ensure you dont have an av delay that could point more to a lower atrial type of situation.

Going more in depth then that you should hone in at 2 places.. Lead II, because its sort of the standard/primary frontal vector.. In short its the monitoring lead.. The lead from which all the textbook examples of normal are drawn.

Next up.. Lead v1. V1 is a great place to look at the atria simply due to its proximity to the RA.

Things to look for? Well size is a good place to start.. P waves should be under 2.5mm.. Shape is another.. They should be rounded as opposed to M shaped, or pointed.. And i should have a nice healthy pr segment.. A pause between atrial and ventricular depolarization, representing appropriate av delay.

Going down the rabbit hole further you can look at organization of v1.. Is my v1 lead sawtooth? How about lead II? If lead II is unreadable/looks like fib, but v1 is organized you could be looking at a fib flutter/organized fib. (This is where literaly half,the atria is in fib and the other half is running a flutter circuit)

In the event of a tachycardia you can measure distances from p waves to r waves to determine the direction of an svt circuit.

Of course marching out p waves is always a good plan as well.. Make sure theres av association.. If your p waves are hidden try to find where they should be and look for morphologic clues as to their presence and nature.

In the event of a pvc dont forget to check for p waves there too.. Try marching out the p's over the pvc and see if you can id continued automaticity. If the sa node is still firing that reduces the probability that the pvc is conducting retrograde at that coupling interval, which can help rule out avrt in some patients.

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NeostigMe is a BSN, RN and specializes in Cardio-thoracic Surgery Recovery and Resuscitation.

31 Posts; 426 Profile Views

Hey there. My experience with intracardiac atrial ECGs are purely with using epicardial wires, so if you are using them in another sense this response may not be helpful.

We use 'atriagrams' (I don't think this is the technical term but what we use ubiquitously on our unit) usually to differentiate atrial flutter/fib , junctional, or NSR. Using the now amplified atrial signal, you can more clearly see atrial activity, if any, and how that correlated with the patients intrinsic ventricular response. I have attached an image which shows how it amplifies the atrial activity in atrial fibrillation and you can see the larger disorganized fib waves and differentiate it from a irregular flutter. Although this was easily seen as flutter in the top rhythm, this technique is useful when the f waves are not as present in the standard ECG.

As for the technique, these atriagrams use the principle of Einthoven's triangle to replace the right arm lead with an atrial epicardial wire. Lead one makes up the electrical activity going from the right arm to the left arm so by replacing the right arm lead (White) with the atrial wire you are kinda 'zooming in' on the atrial activity. You can 'zoom in' further by also replacing the left arm (black) lead with the second atrial wire however I find that this is usually excessive.

So the down and dirty, put your monitor in lead I, touch the metal of one of the epicardial wires to the metal of the white ECG lead, review the monitor and assess for the presence of now amplified atrial activity. If still unsure, you may additionally attach the second atrial lead to the black ECG lead.

I will try to find more examples from my own clinical practice and update the post. *EDIT* I have found more examples and can send them to you if you would like.

a-Surface-ECG-from-patient-in-AF-and-b-Intra-cardiac-atrial-electrograms_Q640.jpg

a-Surface-ECG-from-patient-in-AF-and-b-Intra-cardiac-atrial-electrograms_Q640.jpg

Edited by NeostigMe

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