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PV card: Early repolarization vs STEMI on ECG

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.

References

  1. 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]
  2. 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]
  3. 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]
  4. 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]
  5. 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]
  6. 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]
  7. 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]
By |2021-10-08T09:16:44-07:00May 16, 2013|ALiEM Cards, Cardiovascular, ECG|
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Three predictors for success in cardiac arrest resuscitations

The goal of resuscitation in cardiac arrest is to respond in a timely, effective manner that leads to good patient outcomes.  Resuscitation is not taking an ACLS and BLS course and going through the motions of a code. There have been several studies looking at the quality of intubation and CPR, and their association with good patient outcomes.

By |2019-09-10T13:38:38-07:00May 14, 2013|Cardiovascular|
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PV card: Ectopic pregnancy

Ectopic pregnancy is the leading cause of maternal death in the first trimester of pregnancy. A recent JAMA systematic review,1 from The Rational Clinical Examination series, looked to risk-stratify women in early pregnancy presenting with abdominal pain or vaginal bleeding for ectopic pregnancy. The authors set out to identify the accuracy and precision of elements in the history, physical examination, beta hCG, and ultrasound in ectopic pregnancy.

The systematic review consisted of 14 studies (n=12,101). The search consisted only of English language studies from 1965 to 2012 in which ectopic pregnancy was the final diagnosis with 100 or more patients per article. The summary prevalence of ectopic pregnancy was 15% (95% CI, 10-22%) in women presenting with abdominal pain or vaginal bleeding.

History and Physical

  • Patients symptoms had limited clinical value. Most symptoms had an unhelpful positive LR of less than 1.5.
  • The absence of cervical motion tenderness, peritoneal signs, adnexal mass, or adnexal tenderness did not significantly decrease likelihood of ectopic pregnancy.
  • In descending order, the most significant physical exam findings were:
    • Cervical motion tenderness (Positive LR = 4.9)
    • Peritoneal findings (Positive LR = 4.2-4.5)
    • Adnexal mass (Positive LR = 2.4)
Ultrasound showing normal IUP as shown by the double decidual rings and presence of a yolk sac in a gestational sac

Ultrasound showing normal IUP as shown by the double decidual rings and presence of a yolk sac in a gestational sac

Ultrasound

  • Findings of an intrauterine pregnancy (IUP) such as gestational sac or fetal pole ruled out ectopic pregnancy, except in rare cases of heterotropic prengnacy.
  • Bedside ultrasound is the single most useful diagnostic test. Positive LR = 111. 

Beta-hCG

  • The “discriminatory zone” continues to be debated – no consensus on the number.
  • A one-time hCG level does not rule out ectopic pregnancy.

PV Card: JAMA Review on Ectopic Pregnancy


Adapted from [1]
Go to ALiEM (PV) Cards for more resources.

Reference

  1. Crochet J, Bastian L, Chireau M. Does this woman have an ectopic pregnancy?: the rational clinical examination systematic review. JAMA. 2013;309(16):1722-1729. [PubMed]
By |2021-10-08T09:20:50-07:00May 9, 2013|ALiEM Cards, Ob/Gyn|
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Pediatric Appendicitis: CT or Ultrasound?

Appendicitis is the most common pediatric surgical emergency accounting for 5% of urgent pediatric outpatient visits for abdominal pain. Computed tomography (CT) and ultrasonography (US) are two imaging modalities used in the diagnostic evaluation of acute pediatric appendicitis. Both have decreased the incidence of negative appendectomy results. It is well known that CT has greater diagnostic accuracy than US for diagnosing acute appendicitis, but there is concern over long-term cancer risk, with routine use of CT in children.

What modality should be used for pediatric patients who are suspected of appendicitis?

By |2019-09-10T13:38:32-07:00May 8, 2013|Pediatrics, Radiology|
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Transient Synovitis vs Septic Arthritis of the Hip

Limping is a common reason for parents to bring their children to emergency departments. It is known that 77% of acute, atraumatic limp is dealt with in the ED, and 20% do not even complain of pain.1 Our job as physicians is to complete appropriate assessments to not miss any serious pathology. Specifically, differentiating between transient synovitis (TS) and septic arthritis (SA) of the hip can be difficult and frustrating for everyone. What is your approach?

(more…)

By |2019-09-10T13:38:27-07:00May 1, 2013|Orthopedic, Pediatrics, Radiology|
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