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Monday, 1 October 2012

An Irregular rhythm - #ECGclass Case12



#ECG Class is an educational blog which runs alongside Twitter.
A new ECG "quizz" is launched most Monday evenings, in term time. 
Cases are generally aimed at Primary Care. 
All scenarios are completely fictitious and theoretical, but based on commonly occurring presentations in General Practice. 
This is an educational site, intended for healthcare professionals and shouldn't be construed as patient advice. 

Please use the Hashtag #ECGclass on Twitter, if you want to ask the patient any questions, or request any further investigations. Alternatively, please join in discussion and leave comments below.

Remember there are no right or wrong answers!  

ECG interpretation is often open to debate, and will usually evolve and change as new information becomes available.  Everyone's opinion is valid, and useful for others, as the evolution process takes place. 
Together we will try and form an interpretation based on the trace, and information, we have in front of us. 
Don't worry if you disagree - shout up and share your thoughts - the diagnosis is often arguable on the basis of a 12 lead trace, and may only become more obvious when a longer rhythm strip is available. 

Please feel free to join in, but most important of all, have fun! :-)


#ECG class Case 12

This 88yr old lady attends an appointment with your Health Care Assistant, for her routine annual BP and blood tests. On taking her Blood pressure, your well-trained HCA notices her pulse to be a bit erratic. She phones through to you, as duty GP, and asks you if she should do an ECG?
You have another duty patient with you and are running very late, but are delighted that the HCA has used her initiative here and agree, asking her to pop the ECG in to you before she lets the patient go.

Here is the ECG.


Q1. What are your initial thoughts?

Quick fire - First impressions? First thoughts?

Please feel free to make any comments below, or if using Twitter, by using the hashtag #ECGclass  – Remember, there is no right and wrong with ECG’s, the interpretation of which is an Art form! Just describe what you see. Everyone’s opinion is valid and useful.

If you feel a bit stuck, always remember to go back to basics – refer back to the Methodical Analysis of July’s class if necessary.  

Updated clinical history: She's not on any rate limiting medication. Her only past medical history is hypertension (which is controlled on Amlodipine), Osteoarthritis (simple analgesics PRN) and COPD (inhalers).  She is not on any other medication.


Q2. Can you see any P-waves?
The ECG computer analysis, says this is AF. What do you think? 
Does she needs anticoagulation starting, rate controlling and bundling off to the community arrhythmia clinic for an ECHO?

Q3. Is this Rhythm regular, or irregular? If irregular - is it irregularly irregular, or does it follow a repeating pattern? 
Is the ventricular rhythm (the R-R interval) regular or irregular? If you can see P-waves, is the atrial rhythm (the P-P interval) regular or irregular? 

Discussion

Like many of you, when I first looked at this ECG I was quite confused. It's not an easy one.  The 'AF diagnosis' made me question myself. It is clearly irregularly-irregular, with no fixed pattern, but there are some very clear P-waves which seem appropriately associated with a normal QRS complex....
I considered an altering PR interval, perhaps Wenckebach, but just wasn't happy with any of my thoughts. 

To make it worse, we asked the patient how she felt (!) - she admitted that the previous night, she had an episode when she felt quite light headed, dizzy with a short burst of palpitations.

If we look at the lead II rhythm strip only:

The 1st QRS seen, looks quite normal, and is preceded by a normal looking P wave. 
The 4th and 6th complexes, likewise, look normal. 
The 2nd complex, certainly looks like an atrial ectopic.
The 5th complex looks like and atrial escape beat (kicking in to compensate after a long pause)
The 8th complex is a nodal ectopic (identified by the inverted preceding p-wave)

So, on this ECG alone, we can see lots of different patterns of atrial activity. 
This could be something called "Multifocal atrial tachycardia". 
This is often seen in people with poor lung function, and would fit with this lady's history.

Multifocal Atrial Tachycardia is characterised by an irregular atrial rate greater than 100 beats per minute, with at least 3 morphologically distinct P waves and irregular P-P intervals.  It is often short-lived and self-limiting. Any underlying condition, such as respiratory failure is the mainstay of treatment. Rate control is not important, and may in fact make her feel less well. 

However…. the example above is slightly less fast, and less irrgelular than you might expect with MAT, and there is no marked variation in P wave morphology. 

I felt this rhythm strip was inadequate, and wanted a longer lead II strip:



Does this help any?

General feeling is that this doesn't help enormously. I agree. 
It does however show more 'normal' P waves associated with normal QRS complexes. Also, as she has relaxed in the waiting room, the rate has come down, so it's no longer an atrial tachycadia - multifocal or otherwise. 

But sometimes, a long rhythm strip just isn't long enough....

So lets see a bit more!





So it was a bit mean of me to withold this last strip, but it just goes to show how helpful rhythm strips can be if you wait long enough!

We can now see, at last, a background rhythm. 
The first two beats are sinus beats, followed by an atrial ectopic. This pattern then repeats. This is NOW a clear Atrial trigeminy rhythm. 

Now we have the benefit of this knowledge, we can more confidently assume that the previous strips seen, just represent a mixture of atrial ectopic activity. There is frequent premature atrial activity, but whenever there is a prolonged pause, an atrial escape beat (compensatory beat) kicks in. The rest of the time she's in Atrial bigeminy. 

This doesn't need any further action or treatment. She's well in herself and can be reassured that this is often seen in her age group. 

The main learning point here is - once again - REMEMBER TO IGNORE your ECG machine's interpretation! 

Had the clinician here just glanced at the report, and not the trace, an unnecessary referral - and possibly inappropriate treatment - may have been initiated.

The End. :)
Once again, thank you all so much for taking part!


hw/ecgclass/oct12


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