Thursday, January 2, 2020

How would you manage this patient?

A woman was found outside with altered mental status.

She was GCS 3.  BP 80/40

Here is her ECG:

Sinus bradycardia with Osborn waves.  Temperature was 24.3 degrees Celsius.

She was intubated (carefully, so as not to irritate her heart into ventricular fibrillation).

She requires internal rewarming at this temperature.  External rewarming would be dangerous, as it results in both rewarming shock (hypotension/shock due to shunting of core blood flow to the surface) and "core afterdrop"(shunting of cold surface blood to the core, dropping core temperature).

Because she has an appropriate blood pressure and perfusion, bypass or ECMO is not necessary at this point (but still might become necessary).

This patient was rewarmed with thoracic cavity lavage and intravascular catheter, the same used for induced therapeutic hypothermia.  In this case, the Alsius catheter was placed.  The patient was warmed and did well.

MY Comment by KEN GRAUER, MD (1/2/2020):
This case provides an excellent example in which the History + recognition of Osborn Waves provide the essential clues to facilitate an instant diagnosis of severe Hypothermia. That said, in addition to bradycardia + Osborn waves — there are 2 other ECG findings in Figure-1 that should be noted and followed up after correction of hypothermia.

QUESTION: What are these additional ECG findings?
  • HINT: Were you systematic in your interpretation? Or, did you “jump” at the diagnosis of hypothermia without first surveying the entire tracing?

Figure-1: The ECG shown in this case (See text).

Systematic Interpretation of ECG #1:
  • Rate & Rhythm — There is marked sinus bradycardia at ~48/minute.
  • Intervals — The PR interval is not prolonged (ie, not more than 0.20 second). The QRS complex is narrow (ie, not more than half a large box = 0.10 second in duration). However, the QTc interval is clearly prolongedThis is the 1st additional ECG finding that should be noted. I measure a QT interval of ~590 msec (my measurement in lead V3). Because of the very slow heart rate — the actual QTc will be less than this amount — but the QTc will still be markedly prolonged!
  • Axis — Normal (about +50 degrees).
  • Chamber Enlargement — None.
  • Q-R-S-T Changes — There are small and narrow q waves in multiple leads. Transition occurs early (ie, the R wave becomes taller than the S wave is deep between lead V1-to-V2). There is at least 1-2 mm of Selevation in multiple leads (ie, leads II, III, aVF; V2-thru-V6). This is the 2nd additional ECG finding that should be noted.
  • Finally — There are prominent Osborn Waves in multiple leads (RED arrows in ECG #1).

OSBORN Waves: The Osborn wave has been described as a deflection with a dome or hump that occurs at the point where the end of the QRS complex joins with the beginning of the ST segment. This is the J-Point (ie, it Joins the end of the QRS with the beginning of the ST segment) — so Osborn waves are exaggerated J-point waves. They’ve also been called the “camel-hump” sign.
  • Osborn waves are most commonly associated with significant hypothermia (usually not seen until core temperature is below 90°F). Given the History in this case (ie, in the middle of winter, this patient was “found outside” in shock, and with altered mental status) — as soon as you “touch” this undoubtedly “cold” patient, you’ll KNOW the diagnosis.
  • PEARL  It is important to appreciate that other conditions may also be associated with prominent J-point deflections. Osborn waves have been reported with hypercalcemia, brain injury, subarachnoid hemorrhage, Brugada syndrome, cardiac arrest from VFib — and — severe, acute ischemia resulting in acute MI. The development of Osborn waves in association with acute ischemia/infarction may be a marker of impending VFib (See the 11/22/2019 post on Dr. Smith’s blog).

FINAL THOUGHT: As emphasized by Dr. Smith — highest priority in this case is internal rewarming. After that has been accomplished — the ECG should be repeated!
  • It is highly likely that all 4 of the important findings in this case resulted from this patient’s profound hypothermia. I would expect normalization of the heart rate and QTc interval — along with resolution of Osborn waves and the diffuse ST elevation. BUT — one never knows — and prudence dictates ensuring that the QTc does normalize, and that ST elevation is less (and does not look worrisome) after return to a more normal core temperature.
  • CLICK HERE for a similar case in which bradycardia, QTc prolongation, Osborn waves, and diffuse ST elevation all resolved after correction of hypothermia.

Out THANKS to Dr. Smith for presenting this case!


  1. Early repolarization type 3 will have VT when hypothernia.

    1. Thank you for your comment. I found a detailed review of the Early Repolarization types here — — That said, in my opinion — Dr. Smith reviews the key priorities of internal rewarming that hold true to minimize the chance of VT/VFib regardless of the “type” of repolarization wave.

  2. Can we think of Pericarditis in this case?

    1. One should always consider all possibilities, but the probability of pericarditis is extremely low when there are large J-point notches. Then especially when the temperature confirms them as Osborne waves.

  3. @ ECG Life — I suspect you sent in your question BEFORE I had a chance to publish My Comment. Please take a look at what I wrote (above). You are correct that there is diffuse ST elevation — but this can occur with hypothermia in association with diffuse Osborn waves (as we see in Figure-1 above). I suspect that when the ECG was repeated AFTER correction of hypothermia — that the ST elevation will have largely (if not completely) resolved. Please CLICK HERE under my "Final Thought" to see a case in which this occurred. Only if diffuse ST elevation persisted AFTER correction of hypothermia would I begin to consider acute pericarditis — :)

  4. very cool, i mean cold, case. had a similar case a few months back in "sunny" california. 70 year old male found outside liquor store, was there all night, and he central valley can get super cold overnight. core was 28 degrees. thats when Steve sent me the paper on proper rewarming (that came from his shop), and when i first learned of the Alsius catheter.
    thank you Steve and Ken

    1. THANKS for your "warm" comment Tom! Happy New Year — :)

  5. My understanding is that afterdrop is a myth that came about due to poor core temp measurement modalities. Doug Brown who is probably the foremost expert on the topic of accidental hypothermia has stated this in numerous lectures and papers. His 2012 NEJM article [] and this letter to the editor [] are two examples.

    1. Scott, I'm not ignoring you, just looking up the literature I've found. I was not aware that this is controversial, so thank you!

    2. Scott,
      Thanks for bringing this to my attention. I did not know that it was controversial.
      I asked our resident Hypothermia expert, Doug Brunette. He has been doing hypothermia research in one of the capitals of environmental hypothermia, Minneapolis, since 1985.

      This is what he wrote:

      Hi Steve

      Good question.

      The article you refer to had 3 references showing no afterdrop in a total of 31 patients with an average temperature of 85F warmed with forced air ventilation.

      I think the literature is all over the place on the question of afterdrop - is it real,and if it is, how much afterdrop occurs. Studies using volunteer humans placed into mild hypothermia and then rewarmed using various methods demonstrate an afterdrop of 1C.

      What I do feel strongly about is that moderate and severely hypothermic patients do frequently have a post rescue cardiac arrest. Why this occurs is anybody's guess, including acid-base disturbance, hypoxia, rewarming shock, core afterdrop, mechanical cardiac stimulation, etc. Given the uncertainty due to lack of definitive evidence for the existence of afterdrop, and the phenomenon of post rescue cardiac arrest, I continue to aggressively internally rewarm patients.



  6. Interesting ECG, very ilustrative regarding Osborn waves and hypothermia I learn much here everyday.Thanks a lot! But there are a low amplitude of the P-waves. Is that important in this case?Also there are a R wave progression early in precordial leads(R>S in V2).

    1. @ Unknown — Yes, the P waves are of low amplitude here — and transition is early. I do not believe that either is a sign of hypothermia. That said, there may be MANY changes as a result of markedly reduced core temperature — and there is a good chance that both of these findings might resolve after normal core temperature is restored — :)

  7. There are always interesting ECG cases on this Blog.
    Very rare to find patients with significante hypothermia and ECG Osborn waves here in our tropical region.
    The QTc is really prolonged. Its correction should not be performed by Bazett's formula in this case, which is significantly influenced by HR and is not appropriate for the calculation of QTc when there is bradycardia or tachycardia. When HR is <50 bpm or> 100 bpm, AHA/ACC recommends employing a linear formula such as Hodges or Fridericia. Using the measurements made by Prof. Ken Grauer, QTc=569ms by Hodges, 548ms by Fridericia, and = 0.52s by Hodges. The values are clearly increased here (very high Qtm), but different with Bazett moving away from the other two.

    1. THANKS for your comment Nestor. As I stated above in My Comment — correction needs to be made for the very slow heart rate. I indicate that the true QTc will be LESS than the 590msec, which is the measured QT — but the important point is not to get an exact QTc measurement, but rather to appreciate that the QTc is markedly prolonged. It sounded to me from the description above that the treating providers did not appreciate that. Mais uma vez obrigado pelo seu coment├írio! — :)

    2. Outcomes research shows that QT should not be corrected when heart rate is less than 60. This is partly because bradycardia increases the risk for TdP

  8. I agree wholeheartedly that the QT should NOT be corrected when the heart rate is below 60. The nomogram proves this. We have an article coming out soon discussing this.

    1. Thanks Steve. I knew there was not a lot of "adjustment" of the QTc with bradycardia, but I didn't know there was none. I'll look forward to seeing your article on this topic! — :)


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