The research included 120 patients with acute myocardial infarction with ST-segment elevation, who underwent reperfusion. It has been revealed, that in AMI + ST ischemic myocardial damage are not the same, and there are areas of reversible left ventricular dysfunction, along with the irreversible necrosis. An effective reperfusion during AMI + ST always accompanies by reperfusion injury and the development of "stunned" myocardium. Restoring asynergic contractility of myocardium under stress echocardiography with small doses of dobutamine, determines the improvement of global systolic function and left ventricular remodeling. Reperfusion resulted in a decrease the frequency of signs of heart failure and cardiac arrhythmias in patients with transmural myocardial infarction.