Experimental study of sympathetic nerve on atrioventricular conduction modulation in acute inferior myocardial infarction

Objective: The changes of atrioventricular conduction during acute inferior myocardial infarction（AIMI） related to the right coronary artery and its correlation with sympathetic nerve.Method: A model of AIMI related to ligating the right coronary artery of denervated autonomic nervous cats was proposed.The A-wave,H-wave and V-wave were measured from the His electrode by template matching.The AA,AH,HV intervals with and without sympathetic nerve stimulation were measured respectively.These measurements（in ms） were analyzed in a statistical manner.Results: It could be observed that the AA and AH interval decreased obviously in both cases（normal and ischemia）,but HV interval didn’t change after the stimulation of sympathetic nerve,and it decreased more after controlling the heart rate by pacing.The decreased percentage of AH intervals was（（14±5））%（without pacing） and（23±7）%（with pacing） respectively in normal after sympathetic nerve stimulation;but the decreased percentage of AH intervals was（7±5）%（without pacing） and（12±2）%（with pacing） respectively in ischemia after sympathetic nerve stimulation.The decreasing amplitude were 50%（without pacing） and 48%（with pacing） respectively in ischemia compared with in normal condition.Conclusion: The regulating function of sympathetic nerve on atrioventricular conduction decreased after ischemia related to the right coronary artery,which may be one of the mechanisms that lead to atrioventricular block after acute inferior myocardial infarction.