Here was the initial 12-lead ECG.
Based on this ECG the lead paramedic called a "STEMI Alert" and transmitted the ECG to the receiving hospital.
The on-duty ED physician received the ECG and the paramedic's radio report.
The ED physician called up the patient's records on the computer system. It turned out that the patient had been to the hospital before.
There was a copy of a prehospital 12-lead ECG from March 2009 on file in the patient's chart.
Based on the similarities between this ECG and the ECG recorded on this call (and the fact that the presentation did not exactly scream ACS) the ED physician did not call the "Code STEMI" while EMS was still in the field.
It would prove to be the correct decision.
This is the 12-lead ECG that was captured on arrival.
You will note that this ECG is very similar to the prehospital 12-lead ECG captured back in March 2009. However, it's slightly different from the prehospital 12-lead ECG taken earlier that evening.
Go back up and look at the prehospital 12-lead ECG.
The frontal plane axis is off by about 15 degrees, the T-wave inversion in lead aVL is more subtle, and the R/S ratio in lead V2 is > 1.
Since these findings are not present in the 12-lead ECG taken on arrival at the hospital, it can probably be explained by lead placement.
Paramedics often project that attitude that skin prep and electrode placement are a low priority, but this case demonstrates why it's essential to quality patient care.
With careful lead placement and excellent data quality, the GE-Marquette 12SL interpretive algorithm does not give the ***ACUTE MI SUSPECTED*** message.
In addition, the ST-depression / inverted T-wave was a critical finding on the prehospital 12-lead ECG, because it suggested the possibility of a reciprocal change to the spurious ST-elevation in lead III.
The presence of the inverted T-wave on the "old" ECG made the ED physician take this finding with a grain of salt.
There's nothing wrong with having multiples sets of "critical eyes" looking at an ECG prior to calling in the cavalry, especially for a marginal ECG where it's questionable as to whether or not the "1 mm of ST-segment elevation in 2 or more anatomically contiguous leads" criterion is met.
That's how we minimize false positives, control health care costs, and do the right thing for the patient.
So we're 0 for 1 with our STEMI Alert protocol. However, on this particular day, the system demonstrated a hidden strength! The STEMI Alert allowed for a quick comparison to an "old" ECG.