Features of Heart Failure with Preserved Ejection Fraction in Patients with Chronic Obstructive Pulmonary Disease and Systemic Sclerosis-Associated Interstitial Lung Diseases

<b>Background/Objectives</b>: This study aims to investigate the potential etiopathogenesis of HFpEF development and identify possible different phenotypes of HFpEF in patients with chronic obstructive pulmonary disease (COPD) and systemic sclerosis-associated interstitial lung diseases (SS-ILDs). It could help clinicians improve early HFpEF personalized detection and management. <b>Methods</b>: This study included 150 patients with chronic lung diseases (CLDs), such as COPD and SS-ILD, who were outside of exacerbation, had no history of chronic heart failure (CHF), and had a left ventricular ejection fraction (LV EF) of ≥50%. The functional status of the lungs, heart, endothelial dysfunction, and acid-base balance was assessed. The results obtained were compared in groups of patients with CLD depending on the presence or absence of HF with preserved ejection fraction (HFpEF). The diagnosis of HFpEF was established based on the HFA-PEFF Score classification. Nonparametric statistical methods were used. <b>Results</b>: In patients with CLD, indicators such as age, longitudinal size of the right atrium, mid-regional pro-atrial natriuretic peptide (MR-proANP), and highly sensitive cardiac troponin T (hsTnT) were higher than in the group of patients without HFpEF. In patients with COPD and HFpEF, statistically significant changes were found in the volume of the left atrium. In patients with SS-ILD and HFpEF, statistically significant differenceswere found in SBP before and after the 6 min walk test (6MWT), the Borg scale before 6MWT, MR-proANP, and the longitudinal dimension of the right atrium. <b>Conclusions</b>: The results of our study allow us to identify two different mechanisms of HFpEF development: In patients with COPD, the predominant factor in the development of HFpEF was hypoxia, while in patients with SS-ILD, myocardial dysfunction with remodeling developed against the background of secondary pulmonary hypertension, highlighting the importance of phenotype-specific evaluation. These findings suggest potential approaches for personalized risk stratification and the development of targeted management strategies for patients with HFpEF.