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The current approach to acute myocardial infarction frames patients in terms of ST-elevation myocardial infarction (STEMI) versus non-ST-elevation myocardial infarction (NSTEMI). ST-elevation, as defined by international guidelines, is considered suggestive of acute coronary occlusion (ACO) and an indication for emergent reperfusion. However, under this paradigm, 25%–30% of NSTEMI patients are found to have unrecognised ACO or critical vessel disease on delayed cardiac catheterisation.1 Without emergent reperfusion, these patients have higher mortality than other NSTEMI patients.2 The term ‘STEMI equivalent’ reflects this problem and refers to patients with electrocardiographic presentation concerning for ACO or severe coronary stenosis that would benefit from urgent revascularisation.
We report the case of a man in his 70s with known history of hypertension that presented to the emergency department (ED) with anginal chest pain with 2 hours duration. ECG showed 1.5mm ST-elevation in lead aVR accompanied by 1–2 mm ST-segment depression in eight precordial and limb leads (figure 1A). Serial troponins showed a rise from 27 pg/mL to 293 pg/mL (normal range <34 pg/mL). Chest pain resolved after administration of intravenous nitrates. A diagnosis of NSTEMI was made. On-call cardiology was contacted, and a delayed invasive strategy was planned. Dual antiplatelet therapy (acetylsalicylic acid and clopidogrel) and enoxaparin were started, and the patient was admitted to the internal medicine ward. Troponin peaked at 2443 pg/mL, and repeat ECG showed less-evident ST-elevation in aVR and persistent multilead ST-depression. On the first day of admission, the patient experienced recurring chest pain. On ECG’s revision, cardiology was contacted, and the patient was immediately transferred to the coronary unit. Transthoracic echocardiogram (TTE) showed dilated left ventricle with severe systolic dysfunction, with apical, mid-septal and mid-anterior wall akinesia. Cardiac catheterisation showed 99% stenosis of the left main coronary artery (LMCA) with ostial involvement of the left anterior descending (LAD) and circumflex arteries (figure 2A,B). The patient was submitted to immediate double coronary artery bypass graft (CABG). Postprocedure ECG showed almost complete resolution of the ischaemic changes (figure 1B). Repeat TTE showed improved systolic function, without segmental changes. The patient passed away 1 month after surgery due to infectious complications.
ST-elevation in aVR with coexistent multilead ST-depression indicates severe myocardial ischaemia due to oxygen supply/demand mismatch. In patients presenting with acute coronary syndrome (ACS), it is predictive of critical stenosis of LMCA, proximal LAD or triple vessel disease. Lead aVR is often described as the ‘neglected lead’ because it points to a vector away from left ventricular depolarisation. In fact, ST-elevation in aVR can represent transmural basal septal or right ventricular outflow tract ischaemia, as well as reciprocal change to ST-depression in lateral leads.3 Moreover, the magnitude of ST-elevation in aVR correlates with mortality and the need for CABG in ACS patients.4 In the case presented, ST-elevation in aVR was not appreciated and more than 24 hours elapsed between ED admission and coronary reperfusion. Recognition of this ECG pattern is fundamental in improving patient outcomes. The European Society of Cardiology acknowledges the importance of ST-elevation in aVR with diffuse ST-depression in STEMI and NSTEMI patients.5 6 Nonetheless, and critically, the definition for ST-elevation does not include this pattern. Also, other ECG patterns recognised as STEMI equivalents, such as De Winter’s and Wellen’s, suffer from the current STEMI versus NSTEMI dichotomy.
This case highlights the need to change the STEMI versus NSTEMI paradigm to better identify the ACS patients who would benefit from emergent intervention.
In a little more than 1 hour, after leaving my uncle in the emergency department, I am confronted with a first myocardial infarction and a picture of extreme frailty. Then it was the confrontation of not having an option and advancing towards a surgery that we knew could be fatal. The pandemic made it impossible for me to see my uncle again. My aunt was only able to see him once, a few days before his passing. It is difficult to speak for my uncle, but I think he lived his illness with tranquillity and aware of its severity. He had the necessary lucidity to decide, without hesitation, in the moment he was questioned about the surgery. During his recovery, he was always very calm, cooperative and thankful. I think he parted in peace.
In acute coronary syndrome patients, ST-elevation in aVR accompanied by multi-lead ST-depression is predictive of the need for immediate invasive strategy.
Emergency department physicians should be aware of ST-elevation myocardial infarction (STEMI) equivalent patterns on electrocardiography.
The current STEMI versus non-ST-elevation myocardial infarction paradigm may fail to recognise these patterns that would benefit from urgent revascularisation.
Patient consent for publication
The authors would like to acknowledge Dr Catarina Brizido, that helped in the critical review of this report.
Contributors AM, AG, PC and ML all contributed in the writing and literature review of this case report.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.