Objective: To evaluate the effect of allopurinol on cardiac pre-procedural injury in patients undergoing angioplasty. Design: A prospective, single blinded, randomized controlled trial on patients with ischemic heart diseases who undergoing angioplasty. Setting and conduct: All patients with ischemic heart diseases who undergoing angioplasty in Shahid Madani Hospital will be randomized (using permuted block randomization, block size 2, allocation ratio 1:1) in two groups of allopurinol treated (n=50) and control (n=50). Participants: All consented patients with ischemic heart diseases aged 18-80 who undergoing angioplasty and stent insertion. The exclusion criteria will include elevation of CK-MB and cTnI before PCI, history of CABG during last three months, history of previous MI, renal dysfunction (creatinine above 2.5 mg/dl), unsuccessful PCI, acute MI, cardiogenic shock, dialysis, pregnancy, inability in filling and understanding of the consent form, unconsented patients, patients who want to discontinue the study at any time. Intervention: In allopurinol group, all patients will be received totally 1200 mg of oral allopurinol before PCI plus standard treatment. The control group will be received only standard treatment. Primary outcomes: Change of CK-MB and cTnI level 12 hours before, 8, and 24 hours after PCI in each groups.