Experimental study on efficacy of very low-dose carvedilol in preventing left ventricular remodeling after acute myocardial infarction in rats

Objective To evaluate the efficacy of very low dose carvedilol in preventing left ventricular remodeling(LVRM) after acute myocardial infarction(AMI) in rats.Methods AMI model was made in 130 SD rats by the methods of Olivetti.The surviving rats were randomly assigned to AMI control and very low dose carvedilol groups.Sham operated rats were selected randomly.After Four weeks of therapy,hemodynamic studies and pathologic analysis were performed.After excluding the rats with infarct size35% or 55%,34 rats were left,which comprised AMI(n=11), very low dose carvedilol(n=11) and Sham operated (n=12) groups.Results Compared with sham operated group,left ventricular(LV) end diastolic pressure(LVEDP),volume(LVV) and weight(LVW) were all significantly increased(all P0.001), while LV pressure maximal rate of rise and fall(±dp/dt) as well as their corrected values(±dp/dt/LVSP) were all significantly decreased(P0.01～0.001) in AMI group.In comparison with AMI group,the LVEDP,LVV and LVW were significantly decreased(all P0.001), while ±dp/dt and ±dp/dt/LVSP were significantly increased(all P 0.01) in very low dose carvedilol group,indicating that carvedilol at very low dose is effective.Conclusions Carvedilol at very low dose can prevent LV remodeling,improve hemodynamics and LV function after AMI in rats.