EKG of the Week
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This EKG was done on a 68 year old man with DM and HTN but no prior cardiac disease who presented to the Emergency room with 2 days of chest pain that he thought was indigestion. His only prior EKG was from 3 years ago and it was normal.
+ EKG Interpretation
Dr. Ohlbaum's Explanation
Looking at this tracing in an organized way, there are P waves before every QRS and QRS after every P. The P waves are normal. It is sinus rhythm but the rate is over 100 so it is sinus tachycardia.
The QRS is narrow. What is the axis? It is down in both I and AVF so the axis is un the right upper quadrant and it is isoelectric in AVL so about 240 positive (or 120 negative, depending on which way you want to report it). Let's look at the reason for that odd axis, he has Q in II and only miniscule R in other inferior leads, suggesting possible inferior Ml but no acute looking ST or T changes in those leads. He also has deep Qs in I and AVL. Now look at the V leads. He has a HUGE R in Vl and V2 where there are not usually big Rs and ST depressions in those leads (where there is usually, if anything, a mm or 2 of ST elevation). And then, he loses R wave amplitude going across the precordium, developing deep, wide Qs in VS and V6 (and don't forget those Q waves in I and AVL) along with ST elevation in VS and V6.
So, he has an acute or subacute (since there are already Q waves) STEMI in the lateral wall. But what about that Vl and V2? That is because STEMI extends to his POSTERIOR wall. What can you do to see the posterior wall a bit better?
So, sinus tachycardia, with an old inferior Ml and an acute or subacute lateral and posterior STEMI. What lesion would you expect to do this? His "culprit" lesion at emergent cath was an occlusion of a branch of a dominant circumflex that wrapped around that lateral wall to the posterior wall. He had a stent placed and did quite well. (He also had an old appearing occlusion of a small nondominant rca accounting for the old looking inferior mi, and some disease in his lad which will need stenting electively).
