A prospective evaluation of the electrocardiographic manifestations of hypothermia

Objective: To determine the effects of body temperature, ethanol use, elect rolyte status, and,acid-base status on the electrocardiograms (ECGs) of hyp othermic patients. Methods: Prospective, two-year, observational study of p atients 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 bli nded 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 conse cutive:complexes. Results: 100 ECGs were obtained in 43 patients. Presentin g 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 fibr illation (n = 8), and junctional (n = 1). Osborn waves were present in 37 o f 43 initial ECGs. Of the six initial ECGs that did not have Osborn waves p resent, 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 dec reased (p = 0.0001, r = -0.441). The correlation between temperature and si ze 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 demon strated between the height of the Osborn waves:and the serum electrolytes, including sodium, chloride, potassium, bicarbonate, BUN, creatinine, glucos e, anion gap, and blood ethanol levels. Conclusions::The presence and size of the Osborn waves in hypothermic patients appear to be a function of temp erature. The magnitude of the Osborn waves is inversely correlated with the temperature.