A 50-something with chest pain. Is there OMI? And what is the rhythm?

Written by Willy FrickA man in his 50s with history of hypertension, hyperlipidemia, and a 30 pack-year smoking history presented to the ER with 1 hour of acute onset, severe chest pain and diaphoresis. His ECG is shown:What do you think?The history thus far is highly suggestive of OMI, so we must study the ECG very closely to see if we can confirm this. Looking at the rhythm strip, we see there is more going on than simple sinus rhythm, and in fact there are two different morphologies of QRS complexes. Take a closer look at the rhythm by itself and see if you can figure out what ' s going on before scrolling further.If we set our calipers on the R waves and number them, we see that even though the PR interval shortens and the P wave disappears beneath the R wave, the R wave continues to occur at very regular intervals. That is, until the 7th R wave which comes a little bit sooner than expected.I will leave more detailed rhythm discussion to the illustriousDr. Ken Grauer below, but this use of calipers shows that the rhythm interpretation is: Sinus bradycardia with a competing (most likely junctional) rhythm. The fact that R waves 2 through 6 are junctional does make ischemia more difficult to interpret -- but not impossible. The Queen of Hearts does not care about rhythm analysis, she simply looks at the ECG and decides whether it represents OMI or not. Here is the Queen ' s verdict and her explanation:She sees OMI but with low confidence. I sent this to ...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs