AIM: To evaluate the impact of 10-14-day intravenous administration of meldonium as part of combination therapy in patients with chronic heart failure in the early post-infarction period on the recovery period, structural and functional parameters, and heart rate variability (HRV). SUBJECTS AND METHODS: The investigation enrolled 60 patients (men and women) aged 45 to 75 years at weeks 3-4 after post-myocardial infarction with symptoms of Functional Class II-III heart failure. All the patients underwent 24-hour electrochocardiography monitoring, cardiac echocardiography, and HRV study. After dividing the patients into 2 groups, Group 1 (a study group) (n = 30) was given intravenous meldonium (idrinol) 1000 mg/day in addition to the basic therapy of coronary heart disease. The patients in the study and control (Group 2; n = 30) groups were at baseline matched for age, gender, disease severity, and basic therapy pattern. RESULTS: Following 10-14 days of treatment, both groups showed clinical improvement and the favorable changes in cardiac structural and functional parameters and HRV values, which were more pronounced in the patients receiving meldonium. CONCLUSION: The patients with CHF using meldonium as part of combination therapy in the early post-infarction period were observed to have clinical improvement, a significant reduction in the rate of angina attacks and in the need for nitrates, a decrease in the number of arrhythmic and ischemic episodes, and favorable changes in cardiac structural and functional parameters and HRV values.