Effects of echinochrome on ventricular repolarization in acute ischemia.

BACKGROUND Myocardial ischemic electrophysiological alterations are associated with the generation of reactive oxygen species. However, electrophysiological effects of antioxidants are unclear. Our objective was to determine the effects of the antioxidant echinochrome on ventricular repolarization in a feline model of 30-min ischemia. METHODS AND RESULTS Activation-recovery intervals were measured from 64 ventricular electrograms recorded before and during the LAD ligation in untreated animals (controls, n=5) and animals given echinochrome (1mg/kg, n=5 and 2mg/kg, n=7). In controls, ischemia resulted in the increase of repolarization dispersion, QTc and Tpeak-Tend intervals and precordial T wave amplitude dispersion. Echinochrome attenuated the ischemic increase of repolarization dispersion. The increased dose of echinochrome abolished the ischemic ECG repolarization changes but did not modify the incidence of ventricular arrhythmias. CONCLUSION Echinochrome modified ischemic alterations of repolarization dispersion that were associated with the changes of the body surface T wave amplitude dispersion and Tpeak-Tend interval.