We aimed to study features of clinical course of acute heart failure (AHF) in patients with ST-elevation myocardial infarction (MI) with preserved left ventricular ejection fraction (LV EF). Clinical and echocardiographic data of 299 patients with LV EF > 40% were studied (mean age 58.25±0.71 years, time from ST-elevation MI onset to hospitalization 3.87±0.23 hrs). Study groups were: 1st group (n=84) – patients with LV EF > 40% on the 1st day of MI and AHF symptoms; 2nd group (n=215) – patients without AHF and LV EF > 40%. 1st group’s patients had predominantly anterior localization of myocardial injury and they were older. They also had signs of early heart remodelling with restrictive haemodynamic pattern and more frequent formation of LV aneurysms, more prevalent ventricular arrhythmias (Р<0.05). Presence of AHF on the 1st day of ST-elevation MI in patients with LV EF > 40% was associated with remote myocardial infarction and cardiovascular death during five years of follow-up (р=0.03).