EKG of the Week

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This is a healthy 27 y/o man. It is a routine EKG and he has no complaints.

+ EKG Interpretation

Dr. Ohlbaum's Explanation

This is a kind of cool tracing. but there aretwo issues: the rhythm, and why is everything upside down?

The rhythm: it starts out sinus but it is very slow. And while there are P's before the first 3 and last 2 complexes, there are no P's before the ones in the middle. His basic rhythm is sinus, but as he breathes there is some (normal) sinus arrhythmia and then his rate drops down below the intrinsic rate of his AV node (which is not much slower than his sinus rate) and there are a couple of junctional beats. Then as the sinus rate picks up it begins to capture and the end of the tracing is again sinus rhythm. I think all of this is normal in athletic young soldier.

In athletes, sinus brady with rates as low as 30-40, sinus pauses as long as 2 secs, 1st degree AV block, and even Mobitz I 2nd degree AV block can all occur. Junctional escape complexes and junctional escape rhythms happen too.

Now, why are complexes upside down in so many leads? The whole complex - P, QRS, and T- is upside down in I and AVL. There is a small R in Vl but then there are Qs with no R progression and overall decreasing voltage across the precordium. A big anterolateral Ml would give you Q's in I, Land the precordial leads but not the upside-down P. And, remember I told you this is a healthy young man. I guess the tech could have reversed the limb leads and messed up the V leads at the same time but how likely would that be?

How can we explain all this?


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(The patient had no idea, I think it is interesting that this had not been detected in childhood, through school age exams, military service and exit physicals!)

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