Background: Heart failure is a global public health issue that is associated with increasing morbidity and mortality. Previous studies have suggested that mitochondrial dysfunction plays critical roles in the progression of heart failure; however, the underlying mechanisms remain unclear. Since kinases have been reported to modulate mitochondrial function, we investigated the effects of dual-specificity tyrosine-regulated kinase 1B (DYRK1B) on mitochondrial bioenergetics, cardiac hypertrophy, and heart failure. Methods: We engineered DYRK1B transgenic and knock out mice and used transverse aortic constriction (TAC) to produce an in vivo model of cardiac hypertrophy. The effects of DYRK1B and its downstream mediators were subsequently elucidated using RNA-seq analysis and mitochondrial functional analysis. Results: We found that DYRK1B expression was clearly upregulated in failing human myocardium as well as in hypertrophic murine hearts. Cardiac-specific DYRK1B overexpression resulted in cardiac dysfunction accompanied by a decline in the left ventricular ejection fraction, fraction shortening, and increased cardiac fibrosis. In striking contrast to DYRK1B overexpression, the deletion of DYRK1B mitigated TAC-induced cardiac hypertrophy and heart failure. Mechanistically, DYRK1B was positively associated with impaired mitochondrial bioenergetics by directly binding with STAT3 to increase its phosphorylation and nuclear accumulation, ultimately contributing toward the downregulation of PGC-1α. Furthermore, the inhibition of DYRK1B or STAT3 activity using specific inhibitors was able to restore cardiac performance by rejuvenating mitochondrial bioenergetics. Conclusions: Taken together, the findings of this study provide new insights into the previously unrecognized role of DYRK1B in mitochondrial bioenergetics and the progression of cardiac hypertrophy and heart failure. Consequently, these findings may provide new therapeutic options for patients with heart failure.

Navitoclax, which is a type of senolytic drug, selectively eliminates senescent cells. This study aimed to evaluate the therapeutic potential of navitoclax in treatment of angiotensin II (Ang II)-induced heart failure in mice. Navitoclax or vehicle was administrated in mice with Ang II-induced heart failure. Cardiac function and electrophysiology were assessed before and after administration of navitoclax. Cardiac remodeling, including morphological changes, fibrosis, and inflammatory responses, was analyzed in myocardial tissue. Cellular effects of navitoclax were validated in isolated primary cardiomyocytes and cardiac fibroblasts in vitro. Echocardiography of mice showed that navitoclax improved cardiac dysfunction by improving the left ventricular ejection fraction (vehicle: 45.88 ± 2.19%; navitoclax: 54.70 ± 1.65%, P < 0.01). In cardiac electrophysiological testing, navitoclax increased conduction velocity (vehicle: 1.37 ± 0.05 mm/ms; navitoclax: 1.69 ± 0.08 mm/ms, P < 0.05) and decreased susceptibility to ventricular tachyarrhythmia induced by programmed electrical stimulation. Histopathological staining, immunofluorescence, and western blotting examinations showed that navitoclax ameliorated Ang II-induced cardiac fibrosis, hypertrophy, and the inflammatory response. Moreover, navitoclax eliminated senescent cells by inducing apoptosis. Therefore, navitoclax improved cardiac function and electrophysiological characteristics through decreasing cardiac fibrosis, hypertrophy, and inflammation in mice with heart failure. Pharmacological clearance of senescent cells may be a potential therapeutic approach in heart failure with reduced ejection fraction.

Introduction Catheter ablation of frequent para‐Hisian premature ventricular contractions (PH‐PVCs) is considered to be challenging. The purpose of this study was to evaluate the strategy, potential technical advantages, and clinical outcomes of remote magnetic navigation (RMN) in the ablation of PH‐PVCs. Methods Fifteen consecutive patients with PH‐PVCs were included in this study. Electrical mapping was initially performed in the right ventricular septum by manipulating the RMN catheter with a “U‐curve.” In the case of no optimal ablation site or ablation failure, the ablation catheter was directed to the left ventricular (LV) septum through a transseptal approach for further mapping and ablation by manipulating the RMN catheter with a “reverse S‐curve.” Results Nine of 15 patients were submitted to ablation on the right side. However, ablation success was only achieved in only three (33%) cases. Of the other 12 patients, 11 underwent LV mapping and ablation. In this subset, 9 of 11 (82%) PH‐PVCs were totally eliminated on the left side. Overall, RMN‐guided mapping and ablation successfully eliminated 12 (80%) of 15 idiopathic PH‐PVCs. During follow‐up, the reoccurrence of PVCs was reported in 1 (8%) of 12 patients. No atrioventricular block was observed during or after the procedure. Conclusion RMN‐guided catheter ablation for PH‐PVCs is effective and safe in unselected patients. Due to the excellent reachability and contact with special morphologies of the RMN catheter on both sides of the ventricular septum, RMN can be considered an effective approach for frequent PH‐PVCs.

Background Remote magnetic navigation (RMN)‐guided ablation has become an inspiring method of catheter ablation for tachyarrhythmias. Hypothesis Data from a large‐scale single center may provide further insight into the safety of and the learning curve for RMN‐guided ablation. Methods A total of 1003 catheter ablation procedures using RMN for conditions including supraventricular ventricular tachycardia, atrial tachyarrhythmias, and premature ventricular contraction/ventricular tachycardia (PVC/VT) were retrospectively analyzed from an ablation registry. Procedural outcomes, including procedure time, mapping time, X‐ray time, and RF time, were assessed. The complications were classified into two categories: major and minor. A subanalysis was used to illustrate the learning curve of RMN‐guided ablation by assessing procedure time and total X‐ray time of 502 atrial fibrillation (AF) ablation procedures. Results Among these procedures, 556 (55.4%) were AF and 290 (28.9%) were PVC/VT. Electrical pulmonary vein isolation was achieved in 99.0% of AF procedures, and acute success reached 90.3% in PVC/VT procedures. The overall complication rate was 0.5%. In the subanalysis of AF procedures, the overall procedure time and X‐ray time of procedures were short (125.9 ± 54.6 and 5.3 ± 3.9 minutes, respectively) and proceeded to decrease from the initial 30 procedures to about 300 procedures, where the learning curve reached plateau, demonstrating maximum procedure efficiency. Conclusions RMN‐guided ablation is safe, as verified by very low overall complication rate and reduced X‐ray time. In our study, even the first AF procedures had a relatively low procedure time and total X‐ray time, and procedure efficiency improved during the learning curve.

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Background The development of atrial fibrillation (AF) following valvular heart disease (VHD) remains a common disease and is associated with substantial adverse complications. However, valid molecular diagnostic and therapeutic tools for post-VHD AF have not been fully established. This study was conducted to discover the molecular mechanisms and immune microenvironment underlying AF following VHD. Methods Gene expression profiles of the GSE41177 dataset were assessed to construct a protein–protein interaction network, and then, autophagy-related hub genes were identified. In addition, to determine the functions of immune cell infiltration in valvular AF, we used the CIBERSORT algorithm to estimate the composition of 22 immune cell types in valvular heart disease. Finally, correlation analysis was carried out to identify the relationship between differentially expressed autophagy-related genes (DEARGs) and significant immune cell subpopulations to reveal potential regulatory pathways. Results A total of 153 DEARGs were identified in AF-VHD patients compared with controlled donors. Moreover, we screened the top ten hub nodes with the highest degrees through a network analysis. The ten hub nodes were considered hub genes related to AF genesis and progression. Then, we revealed six significant immune cell subpopulations through the CIBERSORT algorithm. Finally, correlation analysis was performed, and six DEARGs (BECN1, GAPDH, ATG7, MAPK3, BCL2L1, and MYC) and three immune cell subpopulations (T cells CD4 memory resting, T cells follicular helper, and neutrophils) were identified as the most significant potential regulators. Conclusion The DEARGs and immune cells identified in our study may be critical in AF development following VHD and provide potential predictive markers and therapeutic targets for determining a treatment strategy for AF patients.

Introduction: Currently, numerous ablation techniques are available for atrial fibrillation (AF), in addition to manual radio frequency ablation. The aim of this prospective, non-randomized concurrent controlled trial was to compare the mid-term efficacy and procedural outcomes of persistent AF (PerAF) using cryoballoon (CB) and robotic magnetic navigation (RMN). Methods: Two hundred PerAF patients were assigned, in a 1:1 ratio, to undergo catheter ablation using RMN (RMN group) or CB (CB group). The primary endpoint was freedom from AF recurrence following a 3-month period after the index ablation. The secondary endpoint was peri-procedural outcomes, including the total procedure time, left atrial procedure time, fluoroscopy time, and fluoroscopy dose. The Two-step cluster analysis was used to determine the efficacy of RMN and CB between the different groups. The Cox proportional hazard model and restricted cubic spline were used to determine predictors for AF recurrence. Results: At the mean follow-up of 28.1 ± 9.7 months, the primary endpoint was achieved in 71 PerAF patients in the RMN group and in 62 PerAF patients in the CB group (71% vs. 62%, p = 0.158). Compared with CB, RMN-guided ablation led to a longer procedure time (p < 0.001), but with less radiation (p < 0.001). Cluster analysis returned two clusters of patients and RMN was favorable for one cluster (p = 0.037), in which more patients presented with diabetes mellitus and smaller left atria. Conclusions: For patients with PerAF, CB is generally equivalent to RMN-guided ablation with regard to overall efficacy. RMN-guided ablation could be favorable in specific patient populations presenting with diabetes mellitus and smaller left atria.

Background Myocardial infarction (MI) is characterized by the emergence of dead or dying cardiomyocytes and excessive immune cell infiltration after coronary vessel occlusion. However, the complex transcriptional profile, pathways, cellular interactome, and transcriptional regulators of immune subpopulations after MI remain elusive. Methods and Results Here, male C57BL/6 mice were subjected to MI surgery and monitored for 1 day and 7 days, or sham surgery for 7 days, then cardiac CD45‐positive immune cells were collected for single‐cell RNA sequencing to determine immune heterogeneity. A total of 30 135 CD45 + immune cells were partitioned into macrophages, monocytes, neutrophils, dendritic cells, and T or B cells for further analysis. We showed that macrophages enriched for Olr1 and differentially expressed Gpnmb represented 2 crucial ischemia‐associated macrophages with distinct proinflammatory and prophagocytic capabilities. In contrast to the proinflammatory subset of macrophages enriched for Olr1, Gpnmb‐positive macrophages exhibited higher phagocytosis and fatty acid oxidation preference, which could be abolished by etomoxir treatment. In addition to macrophages, MI triggered prompt recruitment of neutrophils into murine hearts, which constituted the sequential cell‐fate from naïve S100a4‐positive, to activated Sell‐high, to aging Icam1‐high neutrophils. In silico tools predicted that the excessively expanded neutrophils at 1 day were attributed to chemokine C‐C motif ligand/chemokine C‐X‐C motif ligand pathways, whereas CD80/inducible T‐cell costimulator (ICOS) signaling was responsible for the immunosuppressive response at day 7 after MI. Finally, the Fos/AP‐1 (activator protein 1) regulon was identified as the critical regulator of proinflammatory responses, which was significantly activated in patients with dilated cardiomyopathy and ischemic cardiomyopathy. We showed the enriched Fos/AP‐1 target gene loci in genome‐wide association study signals for coronary artery diseases and MI. Targeting Fos/AP‐1 with the selective inhibitor T5224 blunted leukocyte infiltration and alleviated cardiac dysfunction in the preclinical murine MI model. Conclusions Taken together, this single‐cell RNA sequencing data lay the groundwork for the understanding of immune cell heterogeneity and dynamics in murine ischemic hearts. Moreover, Fos/AP‐1 inhibition mitigates inflammatory responses and cardiac dysfunction, which might provide potential therapeutic benefits for heart failure intervention after MI.