Surgical treatments of acute myocardial infarction (MI) possess a high clinical effectiveness, but there are fixed limitations, related to the patient's state, which are limited by medical resources and organizational problems. The development of new medical technologies provides a better and effective non-surgical treatment of acute MI and increases long-term prognosis in this category of patients. The study aims to investigate the influence of hyperbaric oxygenation treatment on clinical outcomes (survival rate and recurrent myocardial infarction (rMI)) during the five-year period of monitoring. The study involved 697 patients who suffered from acute MI, having undergone the standard treatment. The patients were randomly divided into two groups: Group 1 (reference, n = 363); Group 2 (test, n = 334). Patients of Group 2 were given the traditional treatment, accompanied with HBOT (isopression for forty minutes at a working pressure of 0.03 MPa). HBOT was applied first through the fifth day following MI. The treatment course included six cycles, once per day. The clinical assessment was focused on clinical outcome: rMI and mortality related to cardiovascular events. HBOT application that accompanied the acute MI with traditional pharmacotherapy has been proved to reduce rMI within five years following inpatient discharge (rMI rate was 14% in the reference group and 5.4% in the test group, χ 2 = 13.3, р < 0.05). The combination of HBOT with traditional methods in treating acute MI makes it possible to raise the five-year survival rate from 84.4% up to 95.9%.