The electrocardiogram in hypothermia.
OBJECTIVE
Hypothermia is known to adversely affect the electrocardiogram (ECG) in many cases. This study set out to determine the incidence of defined cardiac dysrhythmias, J waves, and conduction abnormalities in urban hypothermia.


METHODS
A prospective, multicenter study was carried out to determine the incidence of defined cardiac rhythms in patients suffering from accidental urban hypothermia. The ECGs were independently analyzed by 2 of the authors and placed into 1 of 6 rhythm categories.


RESULTS
Seventy-three ECGs were analyzed. Normal sinus rhythm was the most common rhythm (41%). Overall mortality was 36% (26/73). J waves occurred in 36% of survivors and 38% of non-survivors and were, therefore, not prognostic. Shivering artifact was present in 66% of survivors and 38% of nonsurvivors. Although there was no statistically significant association between J waves and survival (P = .21), the presence of shivering artifact was associated with survival in severe hypothermia (P = .047). Atrial fibrillation and junctional bradycardia were both associated with high mortality.


CONCLUSIONS
This study confirms that the ECG is abnormal in the majority of patients suffering from accidental hypothermia. J waves do not appear to be independently prognostic in hypothermia. The results suggest that the inability to mount a shivering response may be associated with a poorer outcome; this finding requires further study.
Graham
C A
CA
Southern General Hospital, Glasgow, Scotland, United Kingdom. ColinGraham@bigfoot.com
McNaughton
G W
GW
Wyatt
J P
JP
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D004562:Electrocardiography; D004638:Emergency Treatment; D005260:Female; D006801:Humans; D007035:Hypothermia / Q000150:complications*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012606:Scotland / Q000453:epidemiology; D016019:Survival Analysis