Heart failure with mildly reduced ejection fraction: from diagnosis to treatment. Gaps and dilemmas in current clinical practice.

Heart failure (HF) with mildly reduced ejection fraction (HFmrEF) was recently recognised as a distinct clinical entity. Although guideline diagnostic criteria for HFmrEF are well defined, there is substantial variation in clinical characteristics, pathophysiology and prognosis of this group of patients. The heterogeneity in clinical presentations of HFmrEF arises from diverse patients' risk factors, coexisting comorbidities, which modify clinical signs and symptoms, and stage of the disease. On the other hand, HFmrEF shares common clinical features with other HF subgroups. However, the knowledge about the mechanisms and therapeutic approaches in HFmrEF is far from being completely understood. Therefore, HFmrEF represents one of the most intriguing areas of heart failure research. The aim of this review is therefore to highlight the diagnostic challenges in HFmrEF and to provide a constructive appraisal on the pathophysiology of HFmrEF, as well as to discuss the role of pharmacological and nonpharmacological treatment options in patients with HFmrEF.