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Recognition Of Atrial Fibrillation


While reviewing patient care reports over the past few months, I’ve noticed an odd (to me) trend. It seems that some paramedics are having a hard time recognizing Atrial Fibrillation. Mostly, this isn’t important to the care of the patient, but it is quite frankly, something that I consider a basic paramedic skill. A paramedic isn’t much good if he or she can’t recognize cardiac dysrhythmias when he or she sees them on a print out. Despite what the non EMS person might see on TV, trauma is not the cine qua non being a paramedic. I can teach just about anyone how to treat trauma. Actually, in concert with Ambulance Driver have done exactly that with the Shooter Self Care course. Trauma is really pretty easy to treat.

On the other hand, medical calls are not only more complex, they are more interesting. Part of most ALS level medical calls is applying the cardiac monitor/defibrillator/pacer/vital sign checker/MP3 player that we all love to lug up and down stairs. Even if the call doesn’t involve respiratory or cardiac like symptoms there is a good chance that we are going to at least run a rhythm strip on the patient. Just in case, because we hate being surprised. At least I did because in EMS surprises have a 90:10 percent ratio of bad versus good.

Back to my point, which I promise you I actually have. When I was in paramedic school much of the second six weeks (30 hours per week) of didactic revolved around cardiac topics. Rhythm recognition, cardiac treatments, AHA protocols, medications, more medications, and then more medications. We didn’t do 12 lead EKGs then because there weren’t any EMS cardiac monitors that could actually do 12 leads.

The basics of rhythm interpretation were drilled into us as follows.

Rhythm – Regular or Irregular?

Rate – Normal, Fast, Slow?

P Waves – Is there a P wave in front of every QRS complex?

QRS Complexes – Is there a QRS complex after every P Wave?

Is the interval between the P Wave and the QRS Complex normal, long, or short?

QRS Complexes – Normal or wide?

26 years later and I still use those points as the starting point when I teach EKG interpretation or I have to review a call with a medic.

I still use that same Rubric when I look at every EKG strip I see. I expect that is what every paramedic in the world does in some fashion or another. At least I hope so.

So, why am I seeing so many misinterpretations lately?

In part I blame it on over reliance on the computer generated interpretations that all modern cardiac monitor/defibrillator/pacer/vital sign checker/MP3 players have these days. I don’t know the first thing about the computer algorithms that are built into these devices, but they seem to struggle mightily to make most everything a sinus rhythm of some sort or another.

I’ll frequently see a tortuous interpretation that reads something like “Sinus rhythm with frequent PACs, occassional PJCs, and ectopic beats”. The monitor seems to be desperately trying to find a P wave where none exists. Or, it is trying to find those “f” waves that we are taught are the hallmark of Atrial Fibrillation. The problem is that sometimes the baseline is just too fuzzy to really discern either clear cut P waves or f waves.

Here is a nice picture of Atrial Fibrillation compared to a Sinus Rhythm, courtesy of those nice people a Wikipedia.

Notice the nice jumbly line in the Atrial Fibrillation. Like a lot of text book examples, this one is likely generated by a rhythm generator. It’s nice and clean and even a medical student could likely point it out. The problem is that very often the tracing isn’t all that clear and the baseline is fairly muddy.

How about this one?







No neat little f waves there. It gets worse the faster the Ventricular response is too. At some point, up around 200 beats per minute or so it can become almost impossible to tell if the rhythm is regular or irregular. That’s a different topic though, maybe I’ll write a post about that some day.

A computer interpretation of this might read something like “Sinus tachycardia with frequent PACs”. Which it isn’t.

In case you don’t get the idea, I’m usually pretty skeptical of those computer interpretations.

So, what do I tell medics who can’t seem to figure this Atrial Fibrillation thing out?

It’s simple, really. If the rhythm is irregularly irregular, it’s Atrial Fibrillation until proven otherwise.

It’s really that simple. Even Atrial Flutter isn’t usually irregularly irregular. Every other rhythm that features irregularity has a more or less predictable pattern to it. Not Atrial Fibrillation. All bets are off and the rhythm is totally random in it’s irregularity.

It’s important to recognize this rhythm even if the call isn’t “cardiac” in nature. It’s more important to recognize it even more so if the patient doesn’t have a history of Atrial Fibrillation. New onset Atrial Fibrillation can be totally harmless or it can be a sign that something more is going on. If the patient it totally asymptomatic, it’s a good idea to make a note of it in your PCR. I’d be willing to bet someone at the hospital is going to take interest in that fact.

Of course if the rhythm Atrial Fibrillation on the EKG it is incumbent on the paramedic to ask the patient if they have Atrial Fibrillation or an “irregular heartbeat.” And it’s a good idea to look at the patient’s medication list to see if they have any of the common medications prescribed to treat it.

Simple things like that are the difference between an competent paramedic and one who is far more than just competent.

That’s today’s lesson is EKG interpretation. I hope you enjoyed it.

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After a long career as a field EMS provider, I'm now doing all that back office stuff I used to laugh at. Life is full of ironies, isn't it? I still live in the Northeast corner of the United States, although I hope to change that to another part of the country more in tune with my values and beliefs. I still write about EMS, but I'm adding more and more non EMS subject matter. Thanks for visiting.


    • It’s like just about anything else. To be proficient it’s not enough just to practice. You have to use the proper techniques or you are just wasting your time.

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