Can anyone explain J waves to me?

  1. can anyone explain j waves to me? i went to ena symposium yesterday and one of the topics was hypothermia and j waves on an ekg. what do they look like? why does the patient get them? also wondering if anyone can explain the pathophysiology behind not using a bear-hugger on a hypothermic patient with a temp < 90 degrees. all very interesting to me but i can't quite visulaize it yet. anybody know?

    b eyes
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    About b eyes

    Joined: Mar '07; Posts: 70; Likes: 3
    RN; from US
    Specialty: 9 year(s) of experience in ER, Med-surg, ICU


  3. by   Diahni
    b eyes
    I'm just a student, but I find the internet to be fabulous at answering my questions. I typed j waves in google and got the site below. there's plenty more. I especially like the powerpoint lectures I find....

  4. by   f360
    b eyes,

    I'm confused too. I'm not sure why you wouldn't use a bear-hugger on <90 either (~32C) because that temp is categorized as moderate hypothermia (30-34C) and should be treated with active external rewarming i.e. the bear-hugger. Although, a moderately hypothermic patient in cardiac arrest requires CPR and active internal rewarming not just external. In severe hypothermia (<30C) you would institute active internal rewarming in addition to the active external rewarming.

    J-waves are the conduction defect of a cold myocardium. They look like a notch or a bump on the S wave in the QRS complex. They can vary in size depending which lead you're looking at.

    Hope that helps...
  5. by   tookewlandy
    Is the J wave the same thing as the J point the ends at the end of the QRS complex and beginning of the ST segment??

    or are they something else??
  6. by   kmoonshine
    My theory: you can use a bear-hugger on a patient with a temp. <90, but it shouldn't be the only rewarming intervention. As body temperature decreases, vasoconstriction occurs and blood is shunted from the periphery to the vital organs (brain, heart, lungs). Using a bear-hugger alone would promote peripheral vasodilation and surface warming, which would encourage cold blood to circulate. In this situation, the person would need internal warming measures in addition to a bear-hugger, such as warmed fluids, warmed humidified air on a vent, and bypass. Please correct me if I'm wrong.

    We had a patient a few weeks ago with a rectal temp of 84 (and a BG<20), and did all of the above mentioned interventions. I thought for sure he wouldn't make it; a week later I saw him sitting upright in his ICU bed; amazing how the body works sometimes!

    On a side note: research has shown that inducing hypothermia in patients who survive cardiac arrest increases their chances of survivalby by 10%-15%. The push has been for EMT's, paramedics, firefighters, etc. to use this technique in the field since "time is tissue".
  7. by   f360
    My understanding is that J-point elevation that is caused by hypothermia is called a J-wave or an Osborne wave, so yes, it is essentially the same thing. We only use the term J-wave/Osborne wave if the patient has hypothermia.

    J-point elevation can be a normal finding in some patients or a sign of pathology (Brugada syndrome, short QT, hypothermia etc.) but the physiology is the same... it occurs when the transmural voltage gradient becomes exaggerated (epicardium >>> endocardium) and causes the notching.
  8. by   f360
    Circulation (by the AHA) has put out an article with guidelines on Hypothermia in November 2005. It's a great read.
  9. by   MeryMellen
    Maybe it has something to do with not rewarming patients too quickly. If you raise the temperature too quickly in a person with a hypothalmus that is properly funtioning they can have a drop in temperature.
    Last edit by MeryMellen on Mar 22, '07