You are handed an ECG for a 50 year old man with moderate chest pain for 2 hours now and no associated symptoms typical for ACS, PE, aortic dissection, or any other red flags of chest pain. He has no prior ECG’s on file.
- Is this early repolarization or ST elevation MI?
- Should I activate the cardiac catheterization lab?
Image courtesy of Dr. Steve Smith at HQMedEd-ecg.blogspot.com
Here are some great literature-based pearls compiled by Dr. Jason West (@JWestEM), an EM resident from Jacobi/Montefiore.
PV Card: ECG – Early Repolarization vs ST Elevation MI
Adapted from [1–7]
Go to ALiEM (PV) Cards for more resources.
Furthermore, there is a formula to differentiate early repolarization vs STEMI, per Dr. Smith’s publication6:
(1.196 x STE60V3) + (0.059 x QTc) – (0.326 x RA V4)
- STE60V3 = STE elevation height at 60 msec (1.5 small boxes) after the J-point in lead V3 (mm)
- QTc = The computer-read QTc interval
- RA V4 = R wave amplitude in lead V4 (mm)
A result of > 23.4 is predictive of a LAD occlusion causing a STEMI, rather than early repolarization.
P.S. The above ECG image shows early repolarization.
- Brady W, Syverud S, Beagle C, et al. Electrocardiographic ST-segment elevation: the diagnosis of acute myocardial infarction by morphologic analysis of the ST segment. Acad Emerg Med. 2001;8(10):961-967. [PubMed]
- Brady W, Perron A, Syverud S, et al. Reciprocal ST segment depression: impact on the electrocardiographic diagnosis of ST segment elevation acute myocardial infarction. Am J Emerg Med. 2002;20(1):35-38. [PubMed]
- Smith S. Upwardly concave ST segment morphology is common in acute left anterior descending coronary occlusion. J Emerg Med. 2006;31(1):69-77. [PubMed]
- Larson D, Menssen K, Sharkey S, et al. “False-positive” cardiac catheterization laboratory activation among patients with suspected ST-segment elevation myocardial infarction. JAMA. 2007;298(23):2754-2760. [PubMed]
- Nfor T, Kostopoulos L, Hashim H, et al. Identifying false-positive ST-elevation myocardial infarction in emergency department patients. J Emerg Med. 2012;43(4):561-567. [PubMed]
- Smith S, Khalil A, Henry T, et al. Electrocardiographic differentiation of early repolarization from subtle anterior ST-segment elevation myocardial infarction. Ann Emerg Med. 2012;60(1):45-56.e2. [PubMed]
- Chung S, Lei M, Chen C, Hsu Y, Yang C. Characteristics and prognosis in patients with false-positive ST-elevation myocardial infarction in the ED. Am J Emerg Med. 2013;31(5):825-829. [PubMed]