This is the conclusion to 79 year old female CC: Chest pain.
Let’s take another look at the 12-lead ECG.
The treating paramedic immediately (and correctly) identified this as an acute inferior STEMI.
But is it also a right ventricular infarction?
Several of you indicated that you would capture a right-sided 12-lead ECG (or at least modified lead V4R).
The treating paramedic did in fact capture a right-sided 12-lead ECG.
So now that we’ve performed this test we need to interpret it! Is this positive for right ventricular infarction?
Let’s take a look at modified lead V4R.
This doesn’t look particularly impressive but we must remember the rule of proportionality! The smaller the QRS complex the lower the threshold for ST-elevation.
The QRS complexes in modified leads V3R-V6R tend to be small (as they are here) so it’s debatable as to whether or not we need a full 1 mm of ST-elevation to be positive for right ventricular infarction.
Let’s take lead V4R and “stretch” it vertically while preserving the ST/QRS ratio.
To me this is borderline. The higher up in the RCA the occlusion (i.e., the more of the right ventricle that is involved) the more ST-elevation we can expect in lead V4R.
You may recall this graphic from previous posts on right ventricular infarction.
Based on this diagram it seems to me that the occlusion is likely to be in the mid-RCA meaning that the majority of the right ventricle has been spared.
Indeed, the heart rate of 80 and blood pressure of 152/84 bear that out.
It’s still an acute inferior STEMI so I would use NTG and morphine cautiously but I would use them as needed. If you’re concerned you can always obtain IV access first!
As a final thought for the original 12-lead ECG you will note that the ST-elevation in lead III is about the same amplitude as the ST-elevation in lead II.
With a true right ventricular infarction you can expect to see ST-elevation in lead III greater than ST-elevation in lead II.
This patient was delivered straight to a PCI center with prehospital activation of the cardiac cath lab with a presumed diagnosis is acute inferior ST-elevation myocardial infarction.