A prospective evaluation of the electrocardiographic manifestations of hypothermia

Objective: To determine the effects of body temperature, ethanol use, electrolyte status, and,acid-base status on the electrocardiograms (ECGs) of hypothermic patients. Methods: Prospective, two-year, observational study of patients presenting to an urban ED with temperature less than or equal to 95 degrees F (less than or equal to 35 degrees C). All patients had at least one ECG obtained. Electrocardiograms were interpreted by a cardiologist blinded to the patient's temperature. J-point elevations known as Osborn waves were defined as present if they: were at least 1 mm in height in two consecutive:complexes. Results: 100 ECGs were obtained in 43 patients. Presenting temperatures ranged between 74 degrees F and 95 degrees F (23.3 degrees C-35 degrees C). Initial rhythms included-normal sinus (n = 34), atrial fibrillation (n = 8), and junctional (n = 1). Osborn waves were present in 37 of 43 initial ECGs. Of the six initial ECGs that did not have Osborn waves present, all were obtained in patients whose temperatures were greater than or equal to 90 degrees F (greater than or equal to 32.2 degrees C). For the entire group, the Osborn wave was significantly: larger as temperature decreased (p = 0.0001, r = -0.441). The correlation between temperature and size of the Osborn wave was strongest in six: patients with four or more ECGs (range r = -0.644 to r = -0.956, p = 0.001). No correlation could be demonstrated between the height of the Osborn waves:and the serum electrolytes, including sodium, chloride, potassium, bicarbonate, BUN, creatinine, glucose, anion gap, and blood ethanol levels. Conclusions::The presence and size of the Osborn waves in hypothermic patients appear to be a function of temperature. The magnitude of the Osborn waves is inversely correlated with the temperature.