Reperfusion may prevent or reduce the development and extent of necrosis, but may also lead to an increase in reperfusion damage. Experimental studies performed in various animal models of myocardial ischemia have demonstrated the anti-ischemic properties of trimetazidine (TMZ) and have suggested that TMZ has antioxidant properties, without any direct hemodynamic effects. Our study was aimed at investigating the effects of TMZ before thrombolysis in acute anterior myocardial infarction and included 81 patients, hospitalized within 4 hours of the onset of symptoms. Patients were randomly (double-blind) subdivided in two groups The first group (40 patients, Group A, TMZ-pretreatment), received 40 mg TMZ orally about 15 minute before thrombolysis and, subsequently, 20 mg every 8 hours. The second group (41 patients, Group B) received placebo before thrombolysis. Ventricular arrhythmias (VA) due to reperfusion were evaluated in the first 2 hours. VA occurred in 15 of patients in group A, versus 29 in group B, p<0.05. Creatine kinase (CK) normalization time was achieved after 55.7+/-12.5 hours in group A, versus 61.2+/-12.1 hour in group B, p = 0.048. CK peak was 1772+/-890 in group A vs. 2285+/-910 Ul/l in group B, (p = 0.012). In the follow-up (range 6-22 months), there were 4 deaths, two patients in each group. After 180 days from treatment, the TMZ group showed a smaller end systolic volume than the placebo group (echocardiographic data), 46.2+/-12 and 52.8+/-13 ml/m2, respectively, p = 0.037. Our data suggest that TMZ probably reduces reperfusion damage and/or infarct size in patients with anterior AMI subjected to thrombolysis and affects the post-AMI remodeling. Our data must be interpreted with caution because of the selection of patients. These findings require further extensive trials.