Rhythm Nation April 2022: A Case of ECG ST-Elevations

Author: Zachary Moore

Peer Editors: Alec Feuerbach, Nicole Anthony

Faculty Editor: Mark Silverberg

It is just another night at University Hospital of Brooklyn when a 70-year-old female with a past medical history of hypertension, hyperlipidemia, COPD, and hypothyroidism comes in with altered mental status for the past few hours. She reports changes in her speech and shortness of breath. She was recently admitted for sepsis secondary to a urinary tract infection.

Initially, the ED clinicians are concerned that the patient may be having a stroke, and a “stroke code” is called. The patient is immediately pushed to the CT scanner where she has a negative CT head. She is, however, within the “TPA window”. While her labs are pending, the following ECG is obtained.

This ECG is concerning for 1-2 mm ST-elevations in II, III, aVF, V3, and V4 along with T wave inversions in aVR and aVL. Given the limited history, the clinicians activate the STEMI protocol. Cardiology makes plans to bring the patient to the cath lab, and neurology recommends that all cardiologic interventions take precedence. The patient is started on heparin, clopidogrel, and aspirin. However, her family declines any invasive interventions and elects to proceed with medical management only. The patient is admitted to the CCU.

Repeat ECGs show no dynamic changes. The initial troponin is baseline and all three repeat values are within normal limits. Furthermore, she has no signs of infection on her chest x-ray or urinalysis. The blood gas shows carbon dioxide (CO2) retention, and BiPAP is initiated. As her CO2 downtrends, her mental status improves and ultimately returns to baseline. So, was there ever a myocardial infarction (MI)?

Benign Early Repolarization

Benign early repolarization (BER), just like its name states, is thought to be a benign abnormality found on ECG. Interestingly, further studies have raised concern that it may not be as benign as first thought. For example, one study found a higher prevalence of early repolarization in patients with a history of idiopathic ventricular fibrillation (1). Another study found an increased risk of cardiac death in middle-aged patients with early repolarization patterns in inferior leads (2). From an emergency medicine standpoint, however, early repolarization can be considered benign (at least, for the immediate present) compared to its mimics, acute MI.

The ECG pattern of BER typically shows widespread ST-elevations. Most commonly, it is seen in young healthy patients, but there are outliers.

Some features may help differentiate BER from other conditions such as MI and pericarditis. For example, BER characteristically has widespread concave up ST-elevation (mostly in the precordial leads V2-5), slurring or notching at the J point (also called a “fishhook pattern” as shown below), asymmetrical T waves that are concordant with the QRS complex, ST-elevation to T wave ratio <0.25 in V6, and no reciprocal ST-depressions. (More examples of these differences can be seen in a previous post ).

Image From Life in the Fastlane

In this patient’s ECG, we can see the upsloping, concave morphology of the ST segments and though there are T wave inversions, we do not see any reciprocal ST-depressions. Another clue that this is BER is that the ST-elevations do not correspond to a specific vascular territory.

Serial ECGs can also be helpful in identifying dynamic changes of ongoing ischemia — or the lack thereof.

In general, it is important to be aware of MI mimics like BER AND consider the clinical presentation as cardiac catheterization is not without risks. Nonetheless, BER is uncommon in those over the age of 50 years old and VERY rare for those over the age of 70. So, in a case like this with an elderly patient unable to provide clear history, it is reasonable to assume that ST-elevations on an ECG are suggestive of MI, not BER, and to activate the cath lab.