The name STEMI cognitively inspires us to fail at the reperfusion decision. Because we've named the entire AMI paradigm after the ST segment, it is no surprise that we have made little progress in implementing other ECG findings of OMI. The name STEMI makes clinicians believe that the ST segment is the only ECG finding predictive of OMI, and may explain the lack of understanding of the full occlusion and reperfusion sequences of ECG findings in OMI.
If you are able to transfer the patient to a hospital with PCI capability within 1 hour of presentation or they have contraindications to fibrinolytic therapy, it is recommended that you transfer the patient as soon as possible. Otherwise, the goal is fibrinolytic infusion within 30 minutes of arrival to the ER.
STEMI-NSTEMI has been a primary determinant of cath lab activations, hospital metrics, and many other patient factors and outcomes. However, the STEMI criteria fail us frequently, missing upwards of 30% of acute coronary occlusion. Additionally, the STEMI/NSTEMI paradigm is dependent on ST segment elevation defined by millimeter criteria, however many occlusion myocardial infarctions (OMI), have no ST segment elevation at all.
STEMI equivalents represent coronary occlusion without meeting the traditional STE criteria. It's important important to recognize these patterns in a timely fashion.
The pandemic has created new challenges in the emergency department approach to STEMI diagnosis and management. Case reports and series have demonstrated an increased risk of the development of myocardial infarction, acute heart failure, cardiac dysrhythmias and myocarditis in patients with confirmed COVID-19.
There is an interesting discrepancy in medical education. Almost all education takes place in giant academic institutions – ivory towers – so most trainees never see how medicine is practiced “in the real world”. This was especially apparent to me in the management of STEMI.
STEMI is a type of acute coronary syndrome that requires emergency reperfusion therapy.
If a patient meets the Sgarbossa or Smith-modified Sgarbossa criteria in an appropriate clinical context, prompt cardiac catheterisation laboratory activation is appropriate.
In this systematic review and meta-analysis of the diagnostic test accuracy of the post-ROSC EKG to predict acute coronary lesion or revascularization on coronary angiography in adults after cardiac arrest, ST elevation was found to more specific than sensitive test characteristics and all groups and subgroups.
A lot of these treatments have been found to worsen outcomes. Let’s take a walk with old MONAH B for a bit. Morphine: Back in the day with the CRUSADE initiative, morphine was actually found to increase mortality (Meine et al). The thought is that by covering up the pain, concerning changes in patient’s presentation were muted. Furthermore, Morphine has been found to decrease the efficacy of other meds that patient should be getting (i.e. Ticagrelor) So use your clinical decision, if patient’s pain is not improved with Nitro and they continue to have inexhaustible extreme pain- then you might need to treat. Oxygen: Another no. It turns out that O2 has a paradoxical effect on the oxygenation of the heart, actually increasing coronary resistance, decreasing cardiac output and stroke volume and also causing reperfusion injury due to increase oxygen free radicals. In all good ol’ O2 has been shown to increase infarct size and possibly increase mortality risk. (Raut and Maheshwari) So, if they need it (i.e. Sats less than 90%) go ahead and give it- but be discerning because we may actually be doing harm here. Nitroglycerin: Definitely. Give this. See if it helps with pain. Give .4mg every 5 min, or go ahead and start a drip (40mcg per minute) especially if there are signs of heart failure. But remember the contraindications — not in posterior MI, not if taking phsophodiesterace inhibitiors. Aspirin: Yes. Do this. And add on Ticagrelor 180mg or Plavix for dual antiplatelet treatment. Heparin: This one does need a little bit of conversation with your cardiologist. If this patient is not going to undergo PCI- give lovenox instead. This will likely vary hospital to hospital- definitely don’t hold up PCI for the heparin but patient does need it. Beta-Blockers. Don’t give if bradycardia, CHF, reactive airway disease. But if there are no contraindications, go ahead with 25 mg oral metorprolol.
STEMI and Non-ST-elevation myocardial (NSTEMI) can miss a large proportion of acute coronary occlusions; STEMI as a category can miss 30% of occlusion MI up to 50% in left circumflex, and NSTEMI was only associated with total MI in a quarter of cases. The OMI manifesto, introduced by Dr Stephen Smith, Dr Pendell Myers, and Dr Scott Weingart might provide a better solution in the management of ACS. The fundamental question is: Does the patient have an acute coronary occlusion that would benefit from immediate intervention?
Current guidelines from the American College of Cardiology and the American Heart Association define STEMI as a new STE of more than 1 mm in two contiguous chest or limb leads as measured at the J point (excluding V2-V3, where it is higher than or equal to 2 mm in men and higher than or equal to 1.5 mm in women).
These guidelines, however, fail to recognize that STE less than 1 mm in two contiguous leads may still represent an acute total coronary artery occlusion.
Differentiate septal STEMIs from other potentially life threatening mimics.
Occlusion myocardial infarction (OMI) is defined as acute coronary occlusion or near occlusion with insufficient collateral circulation leading to downstream myocardial infarction. Currently, we use STEMI ECG criteria to identify acute coronary OMI in the clinical setting.
Management: Initial pharmacologic management in the emergency department can vary by institution so we recommend consulting with your interventional cardiologist to get on board with their initial treatment regimen. However, it is good to become familiar with all the different possible treatments.
Use in patients ≥21 years old presenting with symptoms suggestive of ACS. Do not use if new ST-segment elevation ≥1 mm or other new EKG changes, hypotension, life expectancy less than 1 year, or noncardiac medical/surgical/psychiatric illness determined by the provider to require admission.
Estimates mortality in patients with STEMI.
The most serious cause of ST elevations on ECG is a ST elevation MI, however there are other possible etiologies. As usual always consider the “worst first”. In borderline or atypical cases remember that timely diagnosis of STEMI is imperative versus diagnosing a benign condition such as early repolarization.
This issue reviews the current literature on emergency department management of STEMI, including recognition of more subtle diagnoses on electrocardiogram, identification of STEMI mimics, an update on treatment therapies, and strategies to achieve more effective management of STEMI across gender and age groups.