Electrocardiographic changes in dog after injection of different doses of the venom of the scorpion Odonthobuthus

There is scant information about biological effects of the venoms of scorpions on different organs. Sixteen healthy native dogs aged about 2 years with average body weight of 18.5 kg of both sexes were selected for this study. Dogs were divided randomly into four equal groups (4 dogs in each group). Clinical signs are recorded and electrocardiogram was obtained for each dog prior to injection of venom. In the control group 1 ml of saline solution was injected and the amount of equal to 0.1, 0.05 and 0.01 mg of venom powder per kg bwt were dissolved in 1 ml saline solution and injected intradermal in the abdominal region or hind limb of each dog in the second, third, and four groups, respectively. Clinical signs and electorcardiogram of each dog were recorded at different time intervals (5, 15, 30, 60, 90, 120, 180, 360 and 24 hours after injection of venom). The results of ECGs, in group 1 and 2 indicated advanced sinus arrhythmia, sinus arrest, sinoatrial standstill, sever bradycardia and tachycardia, first and second degree heart block, premature ventricular contraction, sinus bradycardia and ventricular fibrillation. In group 3, partial sinus arrhythmia, sinus tachycardia, sinus arrest, advanced sinus arrhythmia and tachycardia were observed. In conclusion, the venom of the scorpion Odonthobuthus produces very changes in electrocardiogram by its effects on autonomic system and adrenal gland.