Effect of high doses of nicotine in pigs. I. Changes of the electrocardiogram

Pigs in which venous catheters were positioned for long-term use were injected i.v. with high doses of nicotine in physiol. saline. The LD50 was 2.656 mg/kg body weight. Clinical symptoms were mainly: forced respiration, muscular tremor to tetanoid spasms, cyanosis of the skin, salivation and sometimes vomiting. The degree and duration of symptoms were dose-dependent. Ecg changes in anaesthesized pigs following intravenous nicotine injections of 0.126 mg/kg and 0.378 mg/kg at 15 minutes' interval were immediately commencing disturbances of the heart rate in form of bradycardia and asystolia. After 5 sec we observed extrasystoles, tachycardia, sino-auricular block and AV-block of first and second degree as well as a number of T- and P-changes. Changes of the ecg were observed generally for 10 to 15 min, however, the T-wave remained sometimes negative or biphasic-preterminal negative for some hours.