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The progress of contemporary cardiovascular therapy has led to improved survival in patients with myocardial disease. However, the development of heart failure (HF) represents a common clinical challenge, regardless of the underlying myocardial pathology, due to the severely impaired quality of life and increased mortality comparable with malignant neoplasms. Left ventricular ejection fraction (LVEF) is the main index of systolic function and a key predictor of mortality among HF patients, hence its improvement represents the main indicator of response to instituted therapy. The introduction of complex pharmacotherapy for HF, increased availability of cardiac-implantable electronic devices and advances in the management of secondary causes of HF, including arrhythmia-induced cardiomyopathy, have led to significant increase in the proportion of patients with prominent improvement or even normalization of LVEF, paving the way for the identification of a new subgroup of HF with an improved ejection fraction (HFimpEF). Accumulating data has indicated that these patients share far better long-term prognoses than patients with stable or worsening LVEF. Due to diverse HF aetiology, the prevalence of HFimpEF ranges from roughly 10 to 40%, while the search for reliable predictors and genetic associations corresponding with this clinical presentation is under way. As contemporary guidelines focus mainly on the management of HF patients with clearly defined LVEF, the present review aimed to characterize the definition, epidemiology, predictors, clinical significance and principles of therapy of patients with HFimpEF.

Background Coronavirus disease 2019 (COVID-19) pandemic disorganised healthcare systems and has caused a reduction in the number of hospitalizations and procedures. Cardiac implantable electronic device (CIED) procedure rates and clinical characteristics of their recipients were compared in corresponding weeks of 2019 and 2020 were analyzed. Methods The database of the National Health Fund (NHF) in Poland was retrospectively analyzed. 3206 patients who underwent CIED implantation in the Silesia — a region in Southern Poland comprising an adult population of 3.8 million between 12 th and 31 st week of 2020. Patients were classified into groups: the recipient of an implantable cardioverter-defibrillator or cardiac resynchronization therapy group (ICD/CRT) or pacemaker group (PM). Results During the pandemic a reduction of 39.38% of implantations was observed compared to the same period in 2019 (1210 vs. 1996 patients) and had impacted both groups. Two phases lasting 10 weeks each could be distinguished: total lockdown (maximal reduction) and the recovery phase with growing numbers of procedures. Patient baseline characteristics (sex, age, comorbidities) who were implanted during the COVID-19 pandemic did not differ from the 2019 period. The rate of peri-procedural mortality was also similar. Conclusions During COVID-19 pandemic period a reduction in CIED implantations of all types was observed. Despite the decreased number of performed CIED implants, no differences in baseline patient characteristics were observed.

FMD is related to the number of traditional CVRF/CVDs; however, coronary artery disease has the most significant influence on FMD decrease among analysed factors. The value of FMD assessment in high risk patients is limited.