What does LBBB look like in severe hypothermia? Is there a long QT? Is the QT appropriate for the temperature?

This patient was found down in a Minneapolis winter.  He was very cold with frostbitten fingers and toes.  He was alert but encephalopathic and delirious and very agitated and could not be adequately calmed with olanzapine and lorazepam, so we intubated him.  The first reliable temperature could only be obtained with a Foley thermistor, and it was 26.5 degrees C (79.7 F).His BP was 76/60.  K was 2.8 mEq/L.Here was his first ECG:There is sinus bradycardia with left bundle branch block (LBBB), with proportional ST-T, and VERY long QT and a PVC.  I measure the QT at 800 ms. Notice that there are no Osborn waves, which should always be present at this temperature.  Perhaps LBBB eliminates Osborn waves?  In general, it is probably best to NOT correct the QT when the heart rate is below 60. (See this article by Megan Rischall and me).  If one did correct for a heart rate of 41, one would get 661 by Bazett and 767 by Hodges.LBBB QT interval is distorted by the QRS duration.  To compensate, there are a number of methods to correct for the QT in LBBB. One method is to measure the part of the QT that is most distorted by prolonged repolarization, and which is fairly independent of prolonged depolarization: the Tpeak-Tend interval.  On this ECG,I measure 150 ms for the Tpeak to Tend in V2/V3, and this is very long. By Bazett, this corrects to 124 ms.   Ken Dodd and I published that the typical...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs