Relationship of potassium and calcium to hypothermic ventricular fibrillation

¹ Arctic Aeromedical Laboratory, APO 731, Seattle, Washington

Pentobarbital-anesthetized dogs, cooled in ice water to terminus, were found to have a 96% incidence of ventricular fibrillation. Plasma potassium levels were uniformly depressed at low body temperatures. Treatment with Intravenous potassium chloride, 150– 250 mg/kg, reduced the frequency of fibrillation to 57%. Administration of EDTA (ethylene diamine tetracetic acid), 75 mg/kg in divided doses, lowered serum calcium levels but affected the incidence of fibrillation only slightly. Combined therapy with potassium chloride and EDTA reduced the incidence of ventricular fibrillation to 50%. These results are interpreted as indicating that ionic imbalance observed with hypothermia produces a marked arrhythmic tendency and that proper alteration of plasma potassium levels reduces the danger of fibrillation.