What is this ECG finding? Do you understand it before you hear the clinical context?

Written by Pendell MeyersFirst try to interpret this ECG with no clinical context:The ECG shows an irregularly irregular rhythm, therefore almost certainly atrial fibrillation. After an initially narrow QRS, there is a very large abnormal extra wave at the end of the QRS complex. These are Osborn waves usually associated with hypothermia. There is also large T wave inversion and long QT.Clinical context:A man in his 50s was found down outside in the cold, unresponsive but with intact vital signs. He was intubated on arrival at the ED for mental status and airway protection due to vomiting. Initial vitals included heart rate 109 bpm and BP 145/92 mmHg. They reported that the rectal thermometer simply reported " low " .Here is the initial ECG:A temperature sensing Foley was inserted and reported a core temperature of 26.7 C (80 F).15 minutes after the first ECG, the patient was noted to become bradycardic and hypotensive. Norepinephrine was started, and another ECG was recorded:The patient was rewarmed with external rewarming, heated humidified air via ventilator circuit, warm IV fluid, and Arctic sun device. His temperature was brought back to normal over time in the ICU. He was extubated and had normal neurologic function. He did well and was discharged.See our other blog posts of hypothermia and Osborn waves--Massive Osborn Waves of Severe Hypothermia (23.6 C), with Cardiac Echo--A Pathognomonic ECG. What is it?--Hypothermia and Right Bundle Branch Block, with...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs