Introduction: Long COVID, also referred to as post-acute sequelae of SARSCoV-2 infection (PASC), is defined as a condition occurring after SARS-CoV-2 infection and characterized by the persistence of symptoms lasting at least three months. These symptoms may be continuous, intermittent, remitting, or progressive, and can affect one or multiple organ systems. It is particularly important in older adults due to higher morbidity, mortality, and the risk of functional and cognitive decline. Objective: To examine the prevalence and most common symptoms of long COVID in patients older than 65 years, as well as its impact on daily activities and social isolation. Methods: The study included 100 patients treated at the Geriatrics Department of the University Hospital “Zvezdara,” who had recovered from COVID-19. Data were collected through face-to-face interviews using a questionnaire covering system-specific symptoms, cognitive and psychological complaints, sleep disorders, and social isolation. Results: The mean age of participants was 73.9 ± 6.2 years, and 60% were women. The most common symptoms were fatigue (90%), memory impairment (63%), insomnia (61%), muscle pain (59%), depressive mood (54%), and chest pain (54%). Fatigue was the leading factor limiting daily activities (70%). Social isolation was reported by 65% of respondents, 78% stated that they were less physically active than before, while 44% continued to fear reinfection Conclusion: Long COVID is common in older patients and encompasses a wide range of symptoms that significantly affect daily life and contribute to social isolation. Early recognition and a multidisciplinary approach are essential for the adequate management of these patients.

Introduction: Acute ST-segment elevation myocardial infarction (STEMI) remains a major cause of cardiovascular morbidity and mortality. Despite successful primary percutaneous coronary intervention (pPCI), early myocardial injury and stress may contribute to left ventricular dysfunction. The optimal timing of biomarker assessment after STEMI remains uncertain. Objective: To characterize the early kinetics of soluble suppression of tumorigenicity-2 (sST2), galectin-3 (Gal-3), mid-regional pro-adrenomedullin (MR-proADM), and growth differentiation factor 15 (GDF-15) during the first 96 h after STEMI and identify potentially informative sampling time points for future prognostic assessment. Secondary, exploratory objectives were to evaluate differences in biomarker concentrations according to symptom duration, left ventricular ejection fraction (LVEF), and infarct-related artery. Methods: In this prospective, single-center, exploratory pilot study, patients aged 18–75 years with first STEMI treated with pPCI within 6 h of symptom onset were enrolled between September 2024 and November 2025. Blood samples were collected at admission and 12 ± 4, 24 ± 4, 48 ± 8, and 96 ± 8 h after pPCI. Biomarkers were measured by ELISA, with high-sensitivity cardiac troponin I (hs-cTnI) as a reference marker of myocardial injury. Results: Of 46 enrolled patients, 16 were excluded, mostly due to early discharge, and 30 patients with complete samples at all five time points were included in the analysis (mean age 57.9 ± 11.1 years; 66.7% male). sST2, MR-proADM, and hs-cTnI showed significant temporal variation (all p < 0.001), with the highest measured concentrations of sST2 at 12 h and of MR-proADM at 24 h. No significant change over time was found for Gal-3 and GDF-15. In exploratory analyses, sST2 and MR-proADM concentrations were higher in patients with LVEF < 40%, and sST2 concentrations were higher in patients with left anterior descending artery (LAD) infarction. Symptom duration was not associated with biomarker concentrations. Conclusions: sST2 and MR-proADM show distinct early post-STEMI kinetics, suggesting potentially informative sampling windows for future prognostic studies. Larger prospective studies are needed to confirm these kinetics and the exploratory differences according to left ventricular function and infarct location, and to evaluate the prognostic value of these sampling windows with echocardiographic and clinical follow-up.