Question: In a hypothermia patient, what is the reason behind the possibility of them going into A Fib?
The lower the patient's temperature, the more irritable the myocardium becomes and as such, sensitive to a wide variety of arrhythmias. The most lethal and concerning arrhythmia in hypothermia is actually not atrial fibrillation but rather ventricular fibrillation (VF). Again, as the temperature of the myocardium falls, the closer to the VF threshold the patient becomes. This is why active core re-warming is so essential early in the care of these patients (thus the one shock and go in the directive) since the VF may be refractory to successive countershocks until the patient is re-warmed.