Electrocardiographic studies on fibrillating and nonfibrillating hypothermic dogs with or without previous treatment with acetylcholine or procaine amide

1. 1. The electrocardiographic changes in dogs submitted to deep hypothermia and different types of “antifibrillatory” treatment were investigated. 2. 2. The ECG changes after treatment with acetylcholine-Prostigmin and procaine amide, respectively, are principally the same in the beginning and the end of the period of decreasing temperature. It was noted, however, that to these alterations were added some changes which probably may be attributed to hypothermia itself. The implications of these findings are discussed. 3. 3. In a retrospective investigation with the aim to find out whether any signs could be detected that might be taken as a warning of impending ventricular fibrillation, we could not find any sign whatsoever pointing in that direction. Earlier investigations on this theme are reviewed briefly and the results are discussed.