Article, Cardiology

A new ST-segment elevation myocardial infarction equivalent pattern? Prominent T wave and J-point depression in the precordial leads associated with ST-segment elevation in lead aVr

Case Report

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American Journal of Emergency Medicine

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American Journal of Emergency Medicine 32 (2014) 287.e5-287.e8

A new ST-segment elevation myocardial infarction equivalent pattern? Prominent T wave and J-point depression in the precordial leads associated with ST-segment elevation in Lead aVR

Abstract

Certain acute coronary syndrome electrocardiographic patterns, which do not include ST-segment elevation, are indicative of acute coronary syndrome caused by significant arterial occlusion; these patterns are, of course, associated with significant risk to the patient and mandate a rapid response from the health care team. One such high-risk ECG pattern includes the association of the prominent T wave and J-point depression producing ST-segment depression seen in the precordial leads coupled with ST-segment elevation in lead aVr. This ECG presentation is associated with significant left anterior descending artery obstruction. We report the case of a patient with this ECG presentation who progressed over a very short time to ST-segment elevation myocardial infarction of the anterior wall.

The electrocardiogram (ECG) is frequently the initial Diagnostic tool used by clinicians when evaluating patients suspected of having acute coronary syndrome (ACS). Acute occlusion of a coronary vessel can produce changes on the ECG, including ST- segment elevation; such a finding, in the appropriate setting, can suggest ST-segment elevation myocardial infarction . Certain ACS ECG patterns, which do not include ST-segment elevation, are indicative of ACS caused by significant arterial occlusion; these patterns are, of course, associated with significant risk to the patient and mandate a rapid response from the health care team. Many of these high-risk ECG patterns are well described and recognized, whereas others are not. One such high-risk ECG pattern, recently described, includes the association of the prominent T wave and J-point depression producing ST-segment depression seen in the precordial leads coupled with ST-segment elevation in lead aVr (Fig. 1) [1-3]. This ECG presentation is associated with significant left anterior descending artery (LAD) obstruction and certainly the potential for anterior wall STEMI.

Thus far, this pattern (Fig. 1) has been described in 2 reports [1,2]; the ECG pattern is defined as follows: (1) ST-segment depression at the J-point (N 1 mm) with upsloping ST segments continuing into tall, prominent, symmetrical T waves in the precordial leads (Fig. 1A) and (2) the absence of ST-segment elevation in the affected leads; prominent J-point elevation producing ST-segment elevation of approximately 0.5 to 1.0 mm in lead aVr has also been noted in this ECG presentation (Fig. 1B) [1,2]. The current literature [1,2] suggests that this pattern by itself is a high-risk, ECG presentation; our report reinforces the high-risk nature of this entity and describes a case of short-term progression

to STEMI. In addition, our case also describes an initial emergency physician nonrecognition of the pattern as high risk.

A 50-year old man with a history of hypertension presented to the emergency department with chest pain that he described as “burning like heartburn.” The pain began several hours earlier upon waking that morning. He described the pain as moderate at the center of the chest and was associated with diaphoresis. He took a baby aspirin at home before arrival in the emergency department. Upon presenting to the triage nurse, he was immediately placed in a room and an ECG was obtained (Fig. 2).

The initial ECG demonstrated prominent T waves with J-point depression in the anterior leads; the Marquette 12SL ECG interpre- tation algorithm embedded in the machine used to obtain the ECG interpreted the abnormalities as “anteroseptal infarct, age undeter- mined” and “ST and T wave abnormality consider inferior ischemia.” At this point, the emergency physician did not recognize the ECG as an STEMI equivalent.

Assessment revealed that the patient’s pain had increased to 6 of

10. Initial vital signs were all within normal limits, and there were no physical findings other than diaphoresis. Cardiac workup and initial treatments were pursued. The patient received 0.4 mg of nitroglycerin sublingually, 4 mg of ondansetron (http://www.drugs.com/ ondansetron.html) intraveneously, and 12 mg of morphine intrave- neously. Laboratory studies were obtained, and an echocardiogram was ordered. Initial laboratory studies revealed normal serum markers (troponin and Creatinine kinase, total and MB fraction). The echocardiogram demonstrated septal and apical wall dyskinesis. Interventional cardiology was consulted with subsequent activation of the STEMI ALERT process. A repeat ECG showed anterior STEMI (Fig. 3). The patient received heparin and was taken to the cardiac catheterization laboratory.

Cardiac catheterization showed a 100% mid-LAD occlusion. Balloon angioplasty was successfully performed, and a drug eluting stent was placed. The patient was transferred to the cardiac intensive care unit. Troponin peaked at 200.89 ng/mL. The patient’s course was uncom- plicated, and he was discharged home 2 days later with a moderately reduction in the left ventricular ejection fraction (40%-45%).

In 2008, de Winter et al [1] described a novel ECG pattern associated with proximal LAD occlusion. In their report, they noted that the ECG demonstrates “1 to 3 mm upsloping ST-segment depression at the J point in leads V1 to V6 that continued into tall, positive symmetrical T waves” and “1 to 2 mm ST-segment elevation in lead aVr.” In many cases, this pattern does not progress from the time of the first ECG until after intervention of the occluded vessel [1,2].The pattern (Figs. 1 and 4)

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287.e6 M. Goebel et al. / American Journal of Emergency Medicine 32 (2014) 287.e5287.e8

Fig. 1. A, In lead V3, note the J-point depression (small arrow) with associated ST-segment depression. The T wave is quite prominent, narrow, and symmetric (large arrow). B, ST- segment elevation (arrow) in lead aVr. C, Progression of the ECG findings in panel A over a short period to STEMI with ST-segment elevation.

is defined as follows: (1) ST-segment depression at the J point (N 1 mm) with upsloping ST segments continuing into tall, prominent, symmet- rical T waves in the precordial leads (Fig. 1A) and (2) the absence of ST- segment elevation in the affected leads; prominent J-point elevation producing ST-segment elevation of approximately 0.5 to 1.0 mm in lead aVr has also been noted in this ECG presentation (Fig. 1B) [1,2].The authors of these 2 reports further note that the QRS complexes are most often normal in appearance, including both duration and configuration [1,2]. Less commonly, the QRS complex can be minimally widened and abnormally configured with a loss of normal R wave progression from leads V1 to V6. Interestingly, in sharp contrast with the dynamic ECG changes of Hyperacute T waves in early STEMI, this ECG pattern appears

to be static, persisting from the time of initial recording at presentation until mechanical revascularization occurs; in other words, the pattern resolves either after definitive management of the obstructing lesion in the LAD.

The de Winter ECG pattern is seen in a minority of symptomatic LAD occlusions; in fact, 2% of patients with symptomatic LAD occlusion demonstrate this ECG finding [1]–yet the actual frequen- cy of this ECG presentation is unknown. Although it has been recognized that this ECG pattern is pathognomonic for LAD occlusion, it is not always treated as an STEMI equivalent. The de Winter pattern may, contrary to first reports of the phenomenon, evolve into a traditionally recognizable STEMI pattern, thereby

Fig. 2. The ECG on presentation in the patient with chest pain. Note the J-point depression with associated ST-segment depression. The T wave is quite prominent, narrow, and symmetric. Minimal ST-segment elevation is also seen in lead aVr.

M. Goebel et al. / American Journal of Emergency Medicine 32 (2014) 287.e5287.e8 287.e7

Fig. 3. Progression of the ECG findings from Fig. 2 with the development of STEMI.

Fig. 4. ECG in Fig. 2 (leads V2 and V3 only). A, J-point depression with associated ST-segment depression and ST-segment elevation in lead aVr. The T wave is quite prominent, narrow, and symmetric. B, J-point depression with ST-segment depression (small arrow) and prominent, tall, symmetric T wave (large arrow).

aiding clinicians in making the diagnosis (Figs. 3 and 5). This new “LAD pattern,” in many ways an STEMI equivalent pattern, in some aspects is similar in appearance to the hyperacute T wave of early STEMI. Its structural similarities include a prominent T wave with broad base and asymmetric configuration; an important difference is the lack of dynamic change, which is characteristic of the hyperacute T wave associated with early STEMI.

Recent publications have argued that this ECG pattern should be treated as an STEMI equivalent based on angiographic evidence [4-8]. We describe a case of the “de Winter pattern” evolving to an STEMI ECG pattern within hours of presentation, adding to the body of evidence that this ECG presentation should be considered not only as a high-risk entity but also as an STEMI equivalent.

Practitioners should familiarize themselves with this ECG pattern and treat it as an early indicator of LAD occlusion; furthermore, practitioners must recognize the high-risk nature of this presentation, its “STEMI equivalent” nature, and the tendency to progress to anterior STEMI. In fact, this new finding warrants

immediate recognition by all physicians and paramedics that are responsible for early detection of ACS presentations. There is no question that patients with acute myocardial infarction involving the LAD artery are best managed with emergent catheterization, but current ECG computer interpretations as well as contemporary teaching and guidelines that purely focus on ST-segment elevation will miss this important finding and early coronary intervention, resulting in a potential delay in appropriate therapy.

Mathew Goebel Joseph Bledsoe MD

Intermountain Medical Center, Murray, UT

James L. Orford MBChB, MPH

Intermountain Heart Institute, Murray, UT

Amal Mattu MD

University of Maryland School of Medicine, Baltimore, MD

287.e8 M. Goebel et al. / American Journal of Emergency Medicine 32 (2014) 287.e5287.e8

Fig. 5. Progression of ECG in Fig. 3 to STEMI (leads V2 and V3 only). A, J-point depression with associated ST-segment depression. The T wave is quite prominent, narrow, and symmetric. The area enclosed by the rectangle is seen in panel B. B, Close-up of lead V3 from panel A. Arrow highlights J-point depression with ST segment. C, Development of STEMI. The area enclosed by the rectangle is seen in panel D. D, Close-up of STEMI with J-point elevation and early ST-segment elevation (small arrow) with prominent T wave (large arrow).

William J. Brady MD

University of Virginia School of Medicine, Charlottesville, VA

E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2013.09.037

References

  1. de Winter R, Verouden N, Wellens H, Wilde A. A new ECG sign of proximal LAD occlusion. N Engl J Med 2008;359:2071-3.
  2. Verouden NJ, Koch KT, Peters RJ, et al. Persistent precordial “hyperacute” T-waves signify proximal left anterior descending artery occlusion. Heart 2009;95:1701-6.
  3. Zhang Z, Nikus K, Sclarovsky S. Prominent precordial T waves as a sign of acute anterior myocardial infarction: electrocardiographic and angiographic correlations. J Electrocard 2011;44:533-7.
  4. Fesmire F, Hennings J. A new electrocardiographic criteria for emergent reperfusion therapy. Am J Emerg Med 2012;30:994-1000.
  5. Birnbaum Y, Bayes de Luna A, Fiol M, et al. common pitfalls in the interpretation of electrocardiograms from patients with acute coronary syndromes with narrow QRS: a consensus report. J Electrocard 2012;45:463-75.
  6. Lawner B, Nable J, Mattu A. Novel patterns of ischemia and STEMI equivalents. Emerg Card Care 2012;30:591-9.
  7. Gorgels A. ST-elevation and non-ST-elevation acute coronary syndromes: should the guidelines be changed? J Electrocard 2013;46:318-23.
  8. Rokos I, French W, Mattu A, et al. Appropriate cardiac cath lab activation: optimizing electrocardiogram interpretation and clinical decision-making for acute ST-elevation myocardial infarction. Am Heart J 2010;160:995-1003.

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