How to read atrial ECG?

  1. 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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    About nurs1ng

    Joined: May '12; Posts: 146; Likes: 37


  3. by   2210485
    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.