Background: The recent reclassification of heart failure (HF) patients in the 2016 European Society of Cardiology HF guidelines according to the left ventricular ejection fraction (LVEF) has created a 'grey area' consisting of midrange ejection fraction (mrEF) HF patients with LVEFs of 40-49%. Additionally, there is limited data regarding the in-hospital and long-term prognoses of patients with an mrEF after an ST-elevation myocardial infarction (STEMI). Therefore, we aimed to evaluate the baseline characteristics, in-hospital and long-term mortalities, clinical events in mrEF, preserved ejection fraction (pEF), and reduced ejection fraction (rEF) patients during their hospital stays in a cohort of consecutive STEMI patients who underwent primary percutaneous coronary intervention (PCI). Methods: One thousand two hundred sixty patients were enrolled in the study. The incidences of all the clinical events were recorded during the hospital stays and the mean follow-up duration was 34.4 ± 15.4 months. Results: The incidence of HF signs and symptoms was statistically significant in the mrEF patients when compared to the pEF patients during their hospital stays (3vs. 0.8%, p = 0.05). The overall survival rate in the mrEF patients was between those of the rEF and pEF patients. However, the rate of rehospitalisation due to HF was significantly higher in the mrEF patients when compared to the pEF patients [p (log-rank) < 0.001]. Conclusion: Although the mrEF patients with primary PCI-treated STEMIs exhibited similar baseline clinical characteristics, their in-hospital, long term mortality rates and rate of rehospitalisation due to HF were different from those of the rEF and mrEF patients.
Keywords: Heart failure; ST-segment elevation myocardial infarction; in-hospital prognosis; long-term prognosis; mid-range ejection fraction; primary percutaneous coronary intervention.