First, a tip of the hat to all of our readers who were unafraid to tackle this challenging case. Second, we were very impressed to see the number of readers correctly diagnose and manage this patient. Third, we did not obtain a rectal temperature, and unfortunately no methylene blue was administered.
When we left off last week, our ER team was dealing with a 62 y/o M with back pain +/- CP, hypotensive, tachycardic, hypoxic, dyspneic and diaphoretic. Your eyes and ears alone tell you that something bad is going on. Our differential diagnosis included, foremost, a massive MI or aortic dissection, and briefly, septal or valvular rupture vs endocarditis with septic emboli.
Amongst the many abnormalities in the EMS and ED electrocardiograms, the following findings stood out:
The case highlights a number of the specific changes in the 2013 ACCF/AHA STEMI Guidelines. Since it’s last update in 2006, the new STEMI Guidelines names six changes pertinent to EM. This case touches on three of them:
1) New or presumably new LBBB at presentation occurs infrequently, may interfere with ST-elevation analysis, and should not be considered diagnostic of acute myocardial infarction in isolation.
2) Providers should use Sgarbossa’s Criteria to diagnose a STEMI in the presence of LBBB
3) Widespread ST-depression with ST-elevation in aVR is an indication of proximal LAD or LMCA occlusion.
We shot the CXR below, gave a push dose of pressors, and intubated the patient. Because an STE >1mm in aVR is a strong predictor for early CABG, we gave no thienopyridine platelet inhibitors. Shortly thereafter, the labs returned with a K = 4.7, Cr = 1.3, TnT = 3.7ng/mL.
Ruptures and septic emboli can give a similar EKG. Our quick bedside echocardiogram decreased this likelihood, showing, as expected, diffuse hypokinesis and a poor ejection fraction.
And though an aortic dissection extending into the coronary artery and/or pericardium was a part of our original differential diagnosis, we decided that this rather rare entity should be diagnosed with an aortogram on the catheterization table. Additionally, Cardiothoracic Surgery was notified.
This patient was found to have severe LMCA stenosis with 3-vessel disease. He became hypotensive and bradycardic while on the cath table and required CPR and the placement of an intra-aortic balloon pump with a resultant poor outcome.
There are a number of key teaching points with this case. aVR, the often “forgotten lead”, can provide valuable clinical information. We see in this case that an STE in aVR, especially those >1.5mm, can be associated with a mortality rate as high as 75%. Early recognition of this EKG pattern saves time, guides testing, and informs the decision whether or not to give platelet inhibitors. For a pretty great, pertinent review on STE in aVR, refer to http://lifeinthefastlane.com/ecg-library/lmca.
In addition to the ED crew of Montefiore Medical Center, much thanks to Drs. Meisner and Seigel in the Dept of Cardiology, Jacobi Medical Center for providing insight into this interesting case.
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