Objective: The aim of this study was to compare electrocardiogram (ECG)-12 dynamics depending on the methods of facilitated and primary angioplasty in patients with acute coronary syndrome. The ECG changes in 81 patients - 73 patients with acute myocardial infarction and 8 patients with unstable angina pectoris - were studied. Methods: The ECG analysis before reperfusion therapy and after angioplasty included: dynamics of summary elevation (∑ST+) and depression (∑ST-) of ST segment and changes of summary value of R waves (∑R) in 12 leads. The results were estimated with consideration for the length of the period from the beginning of pain syndrome till treatment and topics of the infraction-related artery. Results: According to our data, there was no difference between facilitated and primary transluminal coronary angioplasty in their effect on focal myocardial variation dynamics and the size of peri-infarction zone. Conclusion: A reliable decrease in elevation and depression of ST segment was observed in reperfusion therapy not later than 6 hours after the beginning of pain syndrome. When reperfusion therapy is begun later, dynamics of summary values of ST segment elevation and depression before and after treatment are not reliable.