This is the conclusion to 66 year old female CC: Chest pressure.
Let’s take another look at the 12-lead ECG.
Let’s break this down 3 leads at a time starting with leads I, II and III.
When you have artifact in a particular cardiac cycle you need to make a conscious effort not to let it influence your interpretation. So let’s look at this again with the second cardiac cycle removed.
Now we can see that ST-elevation is present in leads I, II and III. This would be unusual, but not impossible, for acute STEMI. However, pericarditis has to be a part of our differential diagnosis.
I’m always suspicious of pericarditis when I see ST-elevation in leads I and II. In addition, there is a “notched” J-point in lead I. However, the ST-segment is straight (non-concave) in leads II and III.
Now let’s look at leads aVR, aVL and aVF.
Again we need to make a decision as to which cardiac cycle we “trust”. I’m using the second cardiac cycle in my analysis.
There is a notched J-point in lead aVL but no ST-elevation (and it must be said, no reciprocal change in lead aVL which is almost always present with acute inferior STEMI). Lead III shows non-concave ST-elevation which favors acute STEMI.
Now let’s examine the right precordial leads V1, V2 and V3.
If you take nothing else away from this post, commit this ECG pattern to memory! This is highly suspicious for the reciprocal changes of acute posterior STEMI! The R/S ratio is > 1 in lead V2 (increased R-wave amplitude) and we have > 1 mm ST-depression in leads V1-V3.
Garcia and Holtz call these “carousel ponies”. Imagine the R-wave is a pole and the ST-depression is the saddle. This is an important 12-lead ECG finding and one that must be taken seriously.
If this was the ONLY abnormal finding on this ECG I would call it a STEMI (assuming clinical correlation). But, I would capture modified posterior leads V7-V9 just to have an ECG in my hand that showed the STEMI. Otherwise, there is a chance the patient’s reperfusion would be delayed by a well-meaning clinician who decided it was NSTEMI and not STEMI.
Finally, let’s look at the left precordial leads V4, V5 and V6.
The poor data quality here is unfortunate, because leads V5 and V6 probably show > 1 mm of ST-elevation here (which meet the conventional STEMI criteria). It can’t be stressed often enough. It’s critically important to obtain a clean tracing on a chest pain patient.
In this case, it all worked out well. The paramedics and the emergency physician agreed that it was an acute STEMI and the cardiac cath lab was activated.
Angiography revealed 100% occlusion of the obtuse marginal (major branch of the left circumflex). The lesion was crossed with a wire, the balloon was inflated, and a stent was successfully placed with successful reperfusion.
This ECG reminded me a little bit of the second ECG from 66 year old male CC: Chest pain (at least in the precordial leads).