The aim of the study was to compare the effect of heart rate control with combination of ivabradine with Β-blocker and Β-blocker alone on heart rate variability (HRV), left ventricular (LV) systolic function and plasma NT-proANP in patients with Q-wave myocardial infarction (MI), ejection fraction less than 45% and acute left ventricular failure. We examined 62 patients with first Q-wave MI with an ejection fraction < 45%, resting heart rate > 70 bpm and Killip class I–II on the first day of the disease, 71% of whom received reperfusion therapy. As part of the standard therapy, patients in group 1 (n=30) received metoprolol tartrate (average daily dose 116.5±5.8 mg). Patients in group 2 (n=32), apart from metoprolol tartrate (average daily dose 50.8±1.7 mg), received ivabradine (average daily dose 12.8±0.6 mg), starting from 4–6 days of the disease. Studies of heart rate variability, echocardiographic parameters, as well as concentration of NT-proANP in plasma enzyme immunoassay (ELISA) were performed in all patients at 25 days and in 6 months. After titration of Β-blocker and ivabradine in both groups heart rate was eQually decreased at 25 day and 6 months (all P>0.05). The control of heart rate with ivabradine added to the Β-blocker, compared with monotherapy with higher doses of Β-blocker, was associated with less severe reduction of SDNN and increase of LF/HF after 25 days and 6 months. Decrease of autonomic imbalance according to the temporal and spectral parameters of HRV in these patients after 6 months of therapy with Β-blocker and ivabradine was closely related with improvement of LV systolic function.