Acute heart failure (AHF) is emerging as an increasingly serious issue in the aging global population, and the number of AHF cases is rising annually [1,2]. Although AHF is fundamentally recognized as a heterogeneous condition with many potential comorbidities, its management in the emergency room is largely uniform, according to guidelines [3]. The prognostic impact of emergency room treatment is not well differentiated; however, a better understanding of the myocardial status in the acute phase of AHF may offer insights into improving patient outcomes. Notably, the analysis of mitochondrial dynamics in cardiomyocytes during the acute phase of AHF has rarely been reported.

In this study, we focused on mitochondrial dynamics during the acute phase of AHF. Mitochondria are the primary source of cellular adenosine triphosphate, and when they malfunction, they can become a major source of oxidative stress and trigger both apoptosis and necrosis. Mitochondrial dynamics are normally regulated by quality control mechanisms, including fission and fusion [4], impairment in any of which leads to mitochondrial dysfunction. Maintaining a balance between mitochondrial fusion and fission is therefore crucial for maintaining mitochondrial function in cardiac tissue. Mitochondrial fusion involves the merging of mitochondrial membranes in response to stimulation, and mitochondrial fission is marked by the fragmentation of mitochondria and their networks in response to stress [5,6]. Since it is impossible to directly visualize the mitochondrial dynamics during the acute phase of AHF, we evaluated them using mitochondrial dynamics-related RNAs in previous study [7,8]. We recently conducted clinical research on mitochondria-related miRNAs in patients with HF. Our findings suggest that the circulating levels of miR-140-5p were independently associated with the presence of mitochondrial fission, and that a significant correlation exists between miR-140-5p levels and the mitochondrial area in human endomyocardial biopsy samples. [7] The present study aimed to clarify the role of mitochondrial dynamics in patients with AHF. Identifying mitochondrial dynamics-related RNAs, in particular miR-140, associated with adverse outcomes may help guide future updates in the management of AHF in the acute phase.