Actually, Hyperacute T Waves Can Help Identify Occlusion MI

April 21, 2023

Written by Clark Strunk

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Hyperacute T-waves are best conceptualized as being tall and wide relative to the size of the QRS complex, as well as abnormally symmetric, and can be used to aid in early identification of an acute coronary occlusion.

Why does this matter?
Early identification of patients with an acute coronary occlusion allows for more timely initiation of reperfusion therapies and better patient outcomes. Hyperacute T-waves are one of the first signs of an occlusive MI on ECG, and the recent 2022 ACC Acute Chest Pain Guideline considers hyperacute T-waves to be “STEMI equivalents;” however, there is no universal standard as to what characteristics define them (1).

Waving the way forward…
This editorial was in response to a recent article, that demonstrated that when hyperacute T-waves are defined by amplitude alone, they provide no significant diagnostic value (2). Instead, these authors suggest that hyperacute T-waves are best defined by having an increased area under the curve relative to the QRS amplitude as seen below.

In this example, the ratio of the T-wave area to QRS amplitude was approximately two times higher in case A, a proven LAD occlusion versus normal variant in case B. This large difference is predominantly driven by differences in the QRS amplitude, underscoring the importance of comparing the overall bulk of the T-wave to the size of its preceding QRS complex.  This concept has been retrospectively studied by the authors where they demonstrated that in patients with subtle LAD occlusions, they had significantly greater T-wave to QRS amplitude ratios as well as longer QTc intervals (3).

One of my biggest takeaways from this editorial is that hyperacute T-waves, like all findings on ECG, are best analyzed in their relative proportions, as opposed to an absolute threshold; considering this, as well as their relative symmetry and size compared to prior, along with the appearance of neighboring leads, can help us identify hyperacute T-waves and, ultimately, help more patients.

Source
Hyperacute T-waves Can Be a Useful Sign of Occlusion Myocardial Infarction if Appropriately Defined. Ann Emerg Med. 2023 Mar 3:S0196-0644(23)00025-2. doi: 10.1016/j.annemergmed.2023.01.011. Epub ahead of print.

Works Cited

1. 2022 ACC Expert Consensus Decision Pathway on the Evaluation and Disposition of Acute Chest Pain in the Emergency Department: A Report of the American College of Cardiology Solution Set Oversight Committee. J Am Coll Cardiol. 2022 Nov 15;80(20):1925-1960. doi: 10.1016/j.jacc.2022.08.750. Epub 2022 Oct 11. PMID: 36241466.
2. Hyperacute T Wave in the Early Diagnosis of Acute Myocardial Infarction. Ann Emerg Med. 2023 Feb 9:S0196-0644(22)01327-0. doi: 10.1016/j.annemergmed.2022.12.003. Epub ahead of print. PMID: 36774205.
3. Electrocardiographic differentiation of early repolarization from subtle anterior ST-segment elevation myocardial infarction. Ann Emerg Med. 2012 Jul;60(1):45-56.e2. doi: 10.1016/j.annemergmed.2012.02.015. Epub 2012 Apr 19. PMID: 22520989.