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Monday, 12 November 2012

An Irregular pulse in a young man - #ECGclass case15

#ECGclass case 15

A usually fit and active, 30yr old man comes into see you complaining of intermittent dizzy spells over the past few weeks.

Examination of the cardiovascular system is normal. His pulse is strong, but you detect a slight irregularity. His BP is 108/72.
There is no significant family history of young heart disease, or sudden cardiac death.

However, he is visibly anxious, so you offer to do an ECG.

You get the following trace:

What comments can you make?
Are there any other tests you want?

Please use the #ECGclass to post any questions/comments you'd like to make. 
Remember, everyone's opinion is valid, and many ECG's are open to debate.

The first comment to make is that this isn't a 12 lead ECG and you may want to see the full 12 leads chest leads in order to interpret properly.
However, within the limitations of a 3 lead ECG, what comments can you make?

Is it regular? Or Irregular?
Are there any P waves?
If so, are the P all conducted? 
What about the QT interval?

You also request blood for FBC and Thyroid function, both of which are normal.
He is not on any medication, and has no significant past medical history.

On review, he still seems very anxious, and you ask him more specifically about his concerns.
He tells you he is worried about his heart and blood pressure, because he is under enormous pressure at work. He feels he is coping poorly with the unreasonable demands of his job, but he is under a lot of financial strain, and has no other work options.


In a history such as this, in a young man, the main indication for the ECG - other than reasurrance - is to rule out an inherited channelopathy such as Brugada syndrome or Long QT syndrome; or even HOCM. 

There are no ECG features here suggestive of Brugada syndrome or HOCM, but as 12 lead ECG would be better fro these purposes.
The QT interval is just on the borderline of normal limits (max 11 small squares, or 0.44secs). However, as this rhythm is a little bradycardic, the corrected QT interval will actually be shorter, and so well within normal range. 
This is a normal QT interval. We'll cover long QT syndrome another week.

Within the confines of this 3 lead ECG, we can say the ECG shows sinus rhythm.
Normal P waves are present in front of every QRS complex.  Every P wave seen is conducted. 
The PR interval is constant and of normal duration (3-5 small squares, or 0.12 - 0.20sec).

The P wave and QRS morphology is constant, in any one lead. 
I agree with those of you who thought the P waves looked a bit notched in lead III (and maybe II) - but I suspect these are normal. They are certainly clearly seen, and look normal in Lead I. 

If you are ever in doubt about the presence or  morphology of P waves, the best lead to study the P wave is usually V1, so again, a 12 lead view would be helpful here. 

The P wave rate, however, varies in a cyclical fashion, giving a cyclical variation in the QRS pattern. 


This arrhythmia is usually a normal finding, especially in children and young adults. There is cyclical variation with respiration.  Heart rate increases during inspiration (Reduced vagal tone, with acceleration of the SA node discharge), and decreases during expiration. 
The arrhythmia may be abolished at faster heart rates, such as during exercise etc.  

It is likely that this man'a symptoms are a result of his current stress, and he needs strongly reassuring about his normal heart trace and BP, then his real issues can be addressed. 

The lesson here is once again about confidence. No tricks - It's a normal ECG, and we need to be confident enough to be able to say that.
Well done all! 

Thank you. :)

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