OBJECTIVE: The purpose of this research is to evaluate the efficacy of the lidocaine in myocardial protection with normothermic antegrade blood cardioplegia. METHOD: Twenty six dogs were studied divided at random into two groups of ten and one group of six, depending on which cardioplegic solution they had received. Group I received a cardioplegic solution induction of lidocaine 5mg/kg, 41,6mEq/l of KCl and 180ml of normothermic blood. Group II received the same solution except for the lidocaine and group III received only 180ml of blood. Every 20min 120ml of normothermic blood was reinfused. All dogs underwent cardiopulmonary bypass, two hours of myocardial ischemia and three hours of reperfusion. These dogs were evaluated through operative mortality, myocardial enzymes such as cardiac troponin I and creatine kinase, lactate production, hemodynamic performance measured by ejection fraction and cardiac output, and morphometrics mitochondrial ultrastructural changes. Statistical analysis tests used to compare the results were the Fisher exact test and the two-way Anova. RESULTS: The results have shown that the animals from group I in comparison to those of group II, had no mortality (p=0,08), a lower production of creatine kinase (p<0,05), lower mitochondrial ultrastructural changes (p=0,036) and had no difference with cardiac troponin I production, lactate production and hemodynamic performance. CONCLUSIONS: In conclusion it can be said that lidocaine offered an additional protection to the ischemic myocardial during cardiopulmonary bypass and that animals from groups I and II, with time, showed significant changes, compatible with cellular damage, for all the subjects evaluated.
Myocardial protection; Cardioplegic solution; Lidocaine
