Monday, January 19, 2015

Massive Osborn Waves of Severe Hypothermia (23.6 C), with Cardiac Echo

This patient was found down in the Minnesota Winter.  He felt cold and was unresponsive.  He had palpable pulses at a rate of 30, and his BP was 65/45.  A core temperature was 23.6 degrees Celsius.   Here is his first ECG.
Regular rate of about 30 beats per minute.  It appears to be atrial fibrillation, though it is possible that P-waves are hidden.  If atrial fibrillation, there is AV block and a junctional escape.  
There are MASSIVE Osborn Waves

Here is the bedside echo (this is not slowed down!):

There are very slow contractions with bradycardia, but the ejection fraction is good enough.

Although the patient is hypotensive and has a very low cardiac output, little cardiac output is required in a hypothermic patient with very slow metabolism.  The Postassium was not elevated.

Internal Rewarming was started with an intravascular catheter.  One hour later, the temp was 25.2 and this was the ECG:
The first complex is sinus with a narrow QRS and an Osborn wave.  The subsequent beats appear to be wide ventricular escape beats.  Beats 3, 4, and 5 appear to occur immediately after a P-wave; they appear to have escaped before the P-wave had a chance to conduct.   

Another 1/2 hour after that, the temp was 26.4
Sinus rhythm with 2:1 AV block, with Osborn waves

3 hours later, the temp was 29.0:
Sinus rhythm with 2:1 AV Block.  The heart rate is increasing.

The patient completely rewarmed and did well.


  1. What's about prolonged QT interval?
    any significance?

    1. After correcting for heart rate, it is still long, but not as long. Hypothermia delays repolarization, so prolongs the QT too.

  2. Isn't the last ECG (and maybe also the one before it) a 2:1 AV block?

    1. You are absolutely right. I'll change that.
      Steve Smith


Recommended Resources