Efeitos do pós-condicionamento isquêmico na função ventricular esquerda de corações isolados de ratosEffects of ischemic postconditioning on left ventricular function of isolated rat hearts Abstract Objective: To assess the effects of ischemic postconditioning on left ventricular function in isolated rat hearts.Methods: Twenty-four Wistar rats were used. These hearts underwent perfusion by modified LANGERDORFF method and distributed into three groups: GI -control (n=8); GII -three cycles of postconditioning of 10/10s (n=8); GIIIthree cycles of postconditioning of 30/30s (n=8). After a 15min stabilization period, all hearts underwent 20min of global ischemia following 20min of reperfusion. In the times 0 (control), 5, 10, 15 and 20min of reperfusion, the heart rate (HR), the coronary flow (CoF), the systolic pressure, the (+dP/dt max) contractility and (-dP/dt max) velocity of relaxation were measured. Data were analyzed by ANOVA method followed by Tukey's test for differences between groups and P < 0.05 was considered significant. Rev Bras Cir Cardiovasc 2009; 24(1): 31-37