Aims: Paediatric acute heart failure (AHF) differs from adult cases, and less numerous population limits research aimed at improving clinical practice and prognosis. We aimed to evaluate outcomes and prognostic factors in the paediatric population of AHF patients with left ventricular ejection fraction (EF) < 50%, or systemic right ventricular fractional area change 5% improvement in EF on follow-up echocardiography before discharge (n = 115) and those with EF deterioration, ≤5% EF improvement, or death during hospitalization (n = 47). The study contained 58% males and 42% females. The median age was 1 [interquartile range (IQR) 0–8] year, 14 (IQR 2–101) months. The mortality rate was 12.3%. Acute heart failure aetiologies included congenital heart defects (51.2%), cardiomyopathy (20.4%), infections (14.2%), arrhythmias (11.7%), and others (2.5%). Our study demonstrated independent factors of worse outcomes: cardiomyopathies aetiology [odds ratio (OR) 2.762 (1.210–6.307)], older age [OR 1.006 (1.000–1.011)], and factors of better prognosis: infective aetiology [OR 0.083 (0.010–0.664)], higher EF [OR 0.953 (0.905–0.999)], oxygen saturation (SpO2) [OR 0.951 (0.905–0.992)]. In contrast to CHF exacerbation, de novo AHF had better outcomes (P = 0.014). Conclusion: Acute heart failure with systolic dysfunction in children has an unfavourable prognosis, however most patients improved during hospitalization. In our study, cardiomyopathy aetiology predicted worse outcomes. In turn, infective aetiology, younger age, higher EF, and SpO2 were independent factors of better prognosis.

Pulmonary arterial hypertension (PAH) is a rare heterogeneous disorder in the paediatric population which is mostly associated with congenital heart disease. The management of paediatric idiopathic PAH (IPAH) is difficult due to insufficient comparative data and depends on the results of evidence-based adult studies with several pulmonary vasodilators, as well as the clinical experiences of paediatric experts. Our aim was to present the case of a 9-year-old girl who underwent several methods of treatment, including pharmacotherapy with a significant reaction to treprostinil, as well as bilateral lung transplantation. The patient’s treatment was distinguished by the fact that the dose escalation was as rapid as that observed in the adult population. Due to the limited current evidence and knowledge, the initiation of treatment for these patients remains an individual choice. On the grounds of the number of non-specific symptoms, the diagnosis of this patient was a long process and based mainly on the differential diagnosis. The purpose of this paper is to study this example in order to highlight the importance of early symptoms and the quick implementation of intensive treatment. The applied methods may be useful in doubtful diagnosis processes and treatment procedures in the paediatric population.