Transmural dispersion of repolarization in left hypertrophied ventricle of rabbits during acute ischemia and mechanism of ventricular arrhythmia

Objective:To study the transmural dispersion of repolarization(TDR) in hypertrophied left ventricles(LVH) of rabbits during acute ischemia and to probe the mechanism of ventricular arrhythmia.Method:We recorded the transmembrane action potential in endocardium,epicardium and compared the TDRs of LVH and normal left ventricles respectively during acute ischemia at different basic cycle length(BCL).We also compared the ratio of LVH and control group during ischemia.Result:①Compared to control group,the TDRs of LVH group were significantly elevated depending on the prolongation of ischemic duration and BCL.②The ratio of early after-depolarization(EAD) and delayed after-depolarization(DAD) in LVH group was much higher than that in control group,and then caused tranmural-reentry ventricular arrhythmia in most preparations.It did not happen in control group although DAD occurred in endocardium.Conclusion:TDRs of LVH are dependent on both ischemic duration and BCL;EAD and DAD induced transmural reentry underlies one of the crucial mechanism of hyperthophied left ventricles during ischemia.