Antiarrhythmic effect of acute oxygen-ozone administration to rats

The antiarrhythmic effects of 100; 150; and 300 μg/kg i.p. oxygen/ozone mixture were tested on arrhythmias induced by i) ischemia; ii) ischemia/reperfusion; iii) aconitine (15 μg/kg/i.v.); potassium chloride (1.5% i.v.) in rats. 25 min of cardiac left descending coronary artery ischemia caused severe incidence of ventricular tachycardia, ventricular fibrillation and mortality. These were significantly reduced by pre-treatment of rats with oxygen/ozone mixture at doses of 150 and 300 μg/kg. In separate experiments using a protocol of 5 min ischemia followed by 8 min reperfusion this caused arrhythmias starting within 6±1 s. The incidence of ventricular tachycardia was 100%, while ventricular fibrillation occurred in 75% of the animals and lasted 85±14 s. The mortality was 62.5%. These figures were significantly (Pb0.01) reduced in animals treated with 150 μg/kg oxygen/ozone and a substantial increase observed with 300 μg/kg, whilst not affected by the lower dose of 100 μg/kg. 150 and 300 μg/kg oxygen/ozone prolonged the onset time for the appearance of arrhythmias induced by aconitine (300 μg/kg oxygen/ozone, ∼81% longer). Oxygen/ozone also reduced the ventricular tachycardia duration, ventricular fibrillation incidence, arrhythmia score, and increased the rat's survival rate. As for example, this latter was increased from 25% (aconitine) to 50% (aconitine+oxygen/ozone 150 μg/kg). 100 μg/kg oxygen/ozone was without effect. None of the oxygen/ ozone doses affected the arrhythmias caused by potassium chloride 1.5% i.v. All the oxygen/ozone antiarrhythmic effects were similar to those observed with lidocaine (1.5 mg/kg i.v.). In conclusion, oxygen/ozone has antiarrhythmic effects against arrhythmias caused by aconitine, myocardial ischemia and ischemia/reperfusion.