This ECG was texted to me on my phone, with the words “Asymptomatic with hyperthyroidism:”
|What do you think?
I replied that precordial leads are misplaced and to record it again.
How did I know this? There are well formed R-waves in V1, but none in V2 and V3, then they return in V4. It is possible that there is focal infarction over V3 and V4, but very unlikely.
There had already been two recordings, so the first one was sent too:
|Now the leads are in correct order. What do you think?
There are 2mm STE in V2, 4mm in V3, and 2 mm in V4
My response was:
This is not a myocardial infarction.
Leads V4-V6 are something called “Benign T-wave Inversion“.
Leads V1 and V2 look a lot like old MI (LV aneurysm), although that is unlikely given what we see in V4-V6.
I was not worried about the ST elevation.
Benign T-wave inversion looks just like this: ST elevation with high S-wave voltage in right precordial leads, and ST elevation concordant to a tall R-wave in V4, with a well formed J-wave.
I was then told the clinical history:
46 y.o. male without PMH who presents for weight loss for 1 week and back pain. Patient reports that he had noticed weight lost for a long time, but particularly in the last week.
An ECG was recorded because of a heart rate in the 120s.
He denied chest pain or dyspnea.
His labs had just returned consistent with hyperthyroidism.
The clinicians had been very worried about STEMI, and had appropriately performed a bedside echo.
Here is the parasternal short axis:
There is hyperdynamic function without any wall motion abnormality.
Here is the parasternal long axis:
Again, hyperdynamic without any wall motion abnormality.
The first troponin returned below the level of detection. Remember that an undetectable troponin does NOT rule out STEMI or OMI (Our new terminology: OMI = Occlusion Myocardial Infarction — See OMI Manifesto).
The low probability of OMI is due to:
1. Tachycardia (tachycardia is very unusual in ACS unless there is a second disorder or poor LV function. We will be presenting an abstract on this at SAEM. In our data, of ~2000 patients who had at least 2 troponins drawn within 24 hours, 877 had chest pain, EF greater than 50%, and SBP > 100. Of these, only 23 had a heart rate > 120 but none had type 1 MI.
2. The ECG morphology which, though meeting STEMI criteria, does not have the correct morphology for OMI.
3. The absence of wall motion abnormality, and hyperdynamic function.
4. The absence of chest pain
I advised that they do serial ECG and troponins, but neither Pathway A (cath lab activation) nor Pathway B [Pathway B” is a compromise between activating the cath lab (“Pathway A”) and not activating. It is for emergent cardiologic evaluation for patients who might need emergent angiogram and PCI, but are complicated by an equivocal ECG or complicated medical problems.]
The next ECG was unchanged:
The patient ruled out for MI (all 4 serial troponins below the LoD) and was treated for hyperthyroidism.
See here for more examples of Benign T-wave Inversion, including a video presentation: