Journal of Emergencies, Trauma, and Shock
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Year : 2008  |  Volume : 1  |  Issue : 2  |  Page : 128
ECG J waves


1 College of Medicine, University of South Florida, Bruce B Downs Blvd, Tampa - 33601, USA
2 Department of Medicine, Division of Emergency Medicine, University of South Florida, 2 Columbia Dr, # 504, Tampa - 33606, FL, USA

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How to cite this article:
Sisko M, Peckler BF. ECG J waves. J Emerg Trauma Shock 2008;1:128

How to cite this URL:
Sisko M, Peckler BF. ECG J waves. J Emerg Trauma Shock [serial online] 2008 [cited 2020 Jan 17];1:128. Available from: http://www.onlinejets.org/text.asp?2008/1/2/128/43200


A 19-year-old snow skier was found unconscious by a rescue team after a 2-day search. He was bradycardic, dehydrated, and had sluggish dilated pupils bilaterally. There was no evidence of trauma. The patient was found to have a core body temperature of 82F (27.7C). An electrocardiogram (ECG) was obtained [Figure 1] and this showed the classic ECG changes seen in hypothermia.

Osborne waves, also referred to as J waves, were first described by Tomaszewkski in 1938. The J wave is a positive convex deflection that occurs at the junction of the QRS complex and ST segment, the J-point. They occur most prominently in the inferior leads: II, III, and aVF and the precordial leads: V 5 -V 6 when the core body temperature falls below 32C (89.6F). The magnitude of the deflection above the isoelectric line varies inversely with the fall in core body temperature below 32C. Computer interpretation of ECG has been found to be unreliable in hypothermia, with the J waves in some cases being mistaken for myocardial injury current. When J waves are seen the differential diagnosis includes hypercalcemia, sepsis, CNS lesion, cardiac ischemia, and Brugada syndrome.

The pathophysiology of the J wave is not well understood but it is theorized that the hypothermic state causes an increased repolarization response in phase 1 of the epicardial action potential due to effects on voltage-gated potassium channels. J waves are relatively specific, being seen in 80% of hypothermic patients and are therefore diagnostic. They are not, however, considered pathognomonic as they have also been reported in normothermic patients. In addition to J waves, other nonspecific ECG findings seen in hypothermia include atrial fibrillation and QT interval prolongation. Treatment of the underlying hypothermia by rewarming will cause the J waves to resolve when the core body temperature rises above 32C. Treatment modalities include passive and active external rewarming for mild to moderate hypothermia, with core rewarming being reserved for severe hypothermia.[4]

 
   References Top

1.Danzl, D. Accidental hypothermia. Rosen's emergency medicine: Concepts and clinical practice. 6 th ed. Mosby Elsevier; 2006: Chapter 138.  Back to cited text no. 1    
2.Calkins, H. Cardiac electrophysiology. Cecil medicine. 23 rd ed. Saunders Elsevier; 2008: Chapter 60.  Back to cited text no. 2    
3.Gilbert S. Osborne wave in a patient with tachycardia. Am J Emerg Med 2004;22:623.  Back to cited text no. 3    
4.David S. The EKG and Hypothermia. Am J Emerg Med 2002;22:87-91.  Back to cited text no. 4    

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Correspondence Address:
Bradley F Peckler
Department of Medicine, Division of Emergency Medicine, University of South Florida, 2 Columbia Dr, # 504, Tampa - 33606, FL
USA
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0974-2700.43200

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