J wave
{{short description|Abnormal electrocardiogram finding}}
File:HypothermiaECG.jpg and J wave in a person with hypothermia]]
A J wave — also known as Osborn wave, camel-hump sign, late delta wave, hathook junction, hypothermic wave,{{cite journal |vauthors=Aydin M, Gursurer M, Bayraktaroglu T, Kulah E, Onuk T |title=Prominent J wave (Osborn wave) with coincidental hypothermia in a 64-year-old woman |journal=Tex Heart Inst J |volume=32 |issue=1 |pages=105 |year=2005 |pmid=15902836 |pmc=555838 }} K wave, H wave or current of injury — is an abnormal electrocardiogram finding.{{cite journal |vauthors=Maruyama M, Kobayashi Y, Kodani E, etal |title=Osborn waves: history and significance |journal=Indian Pacing Electrophysiol J |volume=4 |issue=1 |pages=33–9 |year=2004 |pmid=16943886 |pmc=1501063 |url=http://www.ipej.org/4/33 |access-date=2008-12-20 |archive-date=2011-06-15 |archive-url=https://web.archive.org/web/20110615110158/http://www.ipej.org/4/33/ |url-status=dead }}
J waves are positive deflections occurring at the junction between the QRS complex and the ST segment,{{cite web |url=http://library.med.utah.edu/kw/ecg/mml/ecg_6lead018.html |title=ecg_6lead018.html |access-date=2008-12-20}}{{cite web |url=http://www.merck.com/mkgr/mmg/figures/67f1.jsp |title=THE MERCK MANUAL OF GERIATRICS, Ch. 67, Hyperthermia and Hypothermia, Fig. 67-1 |access-date=2008-12-20}} where the S point, also known as the J point, has a myocardial infarction-like elevation.
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Causes
They are usually observed in people suffering from hypothermia with a temperature of less than 32 °C (90 °F),{{cite book |title=Rosen's emergency medicine: concepts and clinical practice 7th edition |last=Marx |first=John |year=2010 |publisher=Mosby/Elsevier|location=Philadelphia, PA |isbn=978-0-323-05472-0 |page=1869 }} though they may also occur in people with very high blood levels of calcium (hypercalcemia), brain injury, vasospastic angina, acute pericarditis, or they could also be a normal variant.{{citation needed|date=February 2021}} Osborn waves on ECG are frequent during targeted temperature management (TTM) after cardiac arrest, particularly in patients treated with 33 °C.{{Cite journal |last1=Hadziselimovic |first1=Edina |last2=Thomsen |first2=Jakob Hartvig |last3=Kjaergaard |first3=Jesper |last4=Køber |first4=Lars |last5=Graff |first5=Claus |last6=Pehrson |first6=Steen |last7=Nielsen |first7=Niklas |last8=Erlinge |first8=David |last9=Frydland |first9=Martin |last10=Wiberg |first10=Sebastian |last11=Hassager |first11=Christian |date=July 2018 |title=Osborn waves following out-of-hospital cardiac arrest—Effect of level of temperature management and risk of arrhythmia and death |url=https://linkinghub.elsevier.com/retrieve/pii/S0300957218302090 |journal=Resuscitation |language=en |volume=128 |pages=119–125 |doi=10.1016/j.resuscitation.2018.04.037|pmid=29723608 }} Osborn waves are not associated with increased risk of ventricular arrhythmia, and may be considered a benign physiological phenomenon, associated with lower mortality in univariable analyses.
History
The prominent J deflection attributed to hypothermia was first reported in 1938 by Tomaszewski. These waves were then definitively described in 1953 by John J. Osborn (1917–2014) and were named in his honor.{{cite journal |last=Osborn |first=J. J. |title=Experimental hypothermia: Respiratory and blood pH changes in relation to cardiac function |journal=Am J Physiol |year=1953 |volume=175 |issue=3 |pages=389–398 |doi=10.1152/ajplegacy.1953.175.3.389 |pmid=13114420 |doi-access=free }} Over time, the wave has increasingly been referred to as a J wave, though is still sometimes referred to as the Osborn wave in most part due to Osborn's article in the American Journal of Physiology on experimental hypothermia.{{cite journal |last1=Serafi |first1=S. |last2=Vliek |first2=C. |last3=Taremi |first3=M. |year=2011 |title=Osborn waves in a hypothermic patient |journal=Journal of Community Hospital Internal Medicine Perspectives |volume=1 |issue=4 |at=Article: 10742 |doi=10.3402/jchimp.v1i4.10742|pmc=3714046 |pmid=23882340 |doi-access=free }}
References
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{{Cardiovascular system symptoms and signs}}
{{Heart diseases}}
{{DEFAULTSORT:Osborn Wave}}