Objectives To study the effects of bradykinin (BK) B2 receptor blockade on infarct size and hemodynamics after myocardial infarction (MI) in rats with angiotensin-converting enzyme (ACE) inhibition therapy. Methods MI was produced by ligating the left coronary artery. The effects of enalapril (500 μg/kg·day), enalapril (500 μg/kg·day) with BK B2 receptor antagonist Hoe-140 (500 μg/kg·day), angiotensin II (Ang II) type 1 (AT1) receptor antagonist losartan (3 mg/kg·day) on infarct size, left ventricular systolic pressure (LVSP), cardiac output index (CI) and stroke volume index (SVI) were observed in rats after MI. Treatments were started on the 2nd day after MI and continued for another 6 weeks. Results Enalapril reduced infarct size and improved CI and SVI compared with the untreated MI group (P<0.05), and these effects of enalapril were significantly blunted by concomitant treatment with Hoe-140 (P<0.05). Losartan was less effective than enalapril. LVSP were unchanged in the three treatment groups. Conclusions BK can reduce infract size and improve hemodynamics in rats following MI. The cardioprotective effects of ACEI partly result from the action of BK exerted through the B2 receptor. Objectives To study the effects of bradykinin (BK) B2 receptor blockade on infarct size and hemodynamics after myocardial infarction (MI) in rats with angiotensin-converting enzyme (ACE) inhibition therapy. Methods MI was produced by ligating the left coronary artery. The effects of enalapril (500 μg / kg · day), enalapril (500 μg / kg · day) with BK B2 receptor antagonist Hoe-140 (500 μg / kg · day), angiotensin II (Ang II) type 1 losartan (3 mg / kg · day) on infarct size, left ventricular systolic pressure (LVSP), cardiac output index (CI) and stroke volume index (SVI) were observed in rats after MI. Treatments were started on the 2nd day after MI and continued for another 6 weeks. Results Enalapril reduced infarct size and improved CI and SVI compared with the untreated MI group (P <0.05), and these effects of enalapril were significantly blunted by concomitant treatment with Hoe-140 (P <0.05). Losartan was less effective than enalapril. LVSP were unchanged in the th ree treatment groups. Conclusions BK can reduce infract size and improve hemodynamics in rats following MI. The cardioprotective effects of ACEI partly result from the action of BK exerted through the B2 receptor.