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Background: The complex relationship between atrial fibrillation (AF) and type 2 diabetes mellitus (T2DM) suggests a potential role for epicardial adipose tissue (EAT) that requires further investigation. This study employs bioinformatics and experimental approaches to clarify EAT's role in linking T2DM and AF, aiming to unravel the biological mechanisms involved., Method: Bioinformatics analysis initially identified common differentially expressed genes (DEGs) in EAT from T2DM and AF datasets. Pathway enrichment and network analyses were then performed to determine the biological significance and network connections of these DEGs. Hub genes were identified through six CytoHubba algorithms and subsequently validated biologically, with further in-depth analyses confirming their roles and interactions. Experimentally, db/db mice were utilized to establish a T2DM model. AF induction was executed via programmed transesophageal electrical stimulation and burst pacing, focusing on comparing the incidence and duration of AF. Frozen sections and Hematoxylin and Eosin (H&E) staining illuminated the structures of the heart and EAT. Moreover, quantitative PCR (qPCR) measured the expression of hub genes., Results: The study identified 106 DEGs in EAT from T2DM and AF datasets, underscoring significant pathways in energy metabolism and immune regulation. Three hub genes, CEBPZ, PAK1IP1, and BCCIP, emerged as pivotal in this context. In db/db mice, a marked predisposition towards AF induction and extended duration was observed, with HE staining verifying the presence of EAT. Additionally, qPCR validated significant changes in hub genes expression in db/db mice EAT. In-depth analysis identified 299 miRNAs and 33 TFs as potential regulators, notably GRHL1 and MYC. GeneMANIA analysis highlighted the hub genes' critical roles in stress responses and leukocyte differentiation, while immune profile correlations highlighted their impact on mast cells and neutrophils, emphasizing the genes' significant influence on immune regulation within the context of T2DM and AF., Conclusion: This investigation reveals the molecular links between T2DM and AF with a focus on EAT. Targeting these pathways, especially EAT-related ones, may enable personalized treatments and improved outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objective: To compare epicardial electrograms between the left atrium (LA) and pulmonary veins (PVs) dynamically at development of persistent atrial fibrillation(AF) in goats PVs. Methods: Ten female goats were instrumented with electrodes at the LA and left side PV. Sustained AF (＞24 h) was induced in the goat by rapid intermittent left atrial pacing for(9.5±2.3)days at a pacing interval of 20 ms for 1 s with a maximum output of 6.0 V, followed by a 2-s period without pacing. Characteristics of PVs and LA epicardial electrograms were analyzed in the development of AF. Results: With prolonged stimulation, the duration of AF was prolonged, complex fractionated atrial electrograms(CFAEs) in LA and was increased gradually, PVs had more CFAEs than LA all the time. When induced AF lasted for more than 24 h, CFAEs in PVs became sustained approximately (2.7%±3.6% vs 92.6%±6.4%, at onset of AF vs AF lasted for more than 24 h, P ＜0.05), and the ratio of CFAEs in PVs was more than that in LA (92.6%±6.4% vs 72.8%±5.3%, P ＜0.05). Conclusion: The epicardial CFAEs are in specific area, which increase along with electrical remodeling. The epicardial CFAEs may play an important role in the maintenance of AF in this model.

Objective: To prospectively clarify the predictive value of high-sensitivity C-reactive protein (hsCRP) on the risk for recurrent atrial arrhythmia in paroxysmal atrial fibrillation (PAF) population who accepted radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF)., Methods: There were 57 consecutive patients (53.32±9.98 years; 42 males) with drug-refractory PAF who underwent RFCA were included. Plasma levels of hsCRP and high-sensitivity cardiac troponin T (hs-cTnT) were measured on admission and first five days after RFCA. Twenty-five patients (43.86%) had early recurrence of atrial fibrillation (ERAF)., Results: Compared to patients without ERAF (no-AF-recurrence group), baseline hsCRP levels had no significant difference in patients with ERAF (AF recurrence group). There were no significant differences in the peak hsCRP and hs-cTnT levels between no-AF-recurrence group and AF recurrence group. However, change of hsCRP level was significantly correlated with change in hs-cTnT level in patients undergoing RFCA ( r =0.268, P =0.044)., Conclusions: Among those AF patients undergoing ablation, change of hsCRP level could be for the myocardial injury related to RFCA procedure, which may not be a risk factor to predict ERAF. The variety of hsCRP level may be related to the degree of myocardial injury induced by RFCA.

Objective: To investigate the effects of atrial excitable period (EP) on the stability of atrial fibrillation (AF) in goats., Methods: Ten female goats were instrumented with epicardial electrodes patches on the left atrium (LA) free wall. AF was induced and maintained by a home-made stimulator with frequency of 50 Hz at a 1-second duration and a 2-seconds interval. The stimulator was disconnected regularly. AF-induced duration, average AF cycle length (AFCL), and atrial effective refractory period during AF (ERP(AF)) were measured; EP was calculated by AFCL-ERP(AF)., Results: Eight goats were studied. Persistent AF (> 24 h) could be induced in all the 8 goats within 6-16 days. When the induced AF lasted for 3-10 min or 24 h, the AFCL was 98.3 ms +/- 11.0 ms and 84.9 ms +/- 5.2 ms (P < 0.05), respectively, ERP(AF) was 90.5 ms +/- 13.2 ms and 63.0 ms +/- 4.8 ms (P < 0.05), respectively, and EP was 7.8 ms +/- 2.4 ms and 21.9 ms +/- 3.5 ms (P < 0.05), respectively., Conclusion: The decrease in ERP(AF) is more significant than the shortening in AFCL, resulting in the gradually widening of EP which may contribute to the perpetuation of AF.