Pulsed electric field is an emerging energy source for cardiac catheter ablation. It creates pores in the cell membrane through high-voltage pulsed electric field, leading to cell apoptosis or necrosis. Pulsed field ablation (PFA) offers several advantages, including relatively selective myocardial injury, rapid lesion formation, and temperature-independent lesion creation. It has been widely applied in catheter ablation therapy for atrial fibrillation. Currently, cutting-edge research on PFA is advancing into the field of ventricular arrhythmias. This article reviews the latest developments in PFA for the treatment of ventricular arrhythmias based on recent research findings.

This article delineates the procedures of petal-shaped pulsed field ablation (PFA) catheter, which include the puncture of the interatrial septum, insertion of the PFA catheter, implementation of the “231” ablation strategy, and verification of pulmonary vein isolation. Additionally, it explores operational techniques to increase the success rate of pulmonary vein isolation, such as the adjustment of the catheter's rotation angle, supplementary ablation between adjacent pulmonary veins, management of common pulmonary vein trunks, and ablation manipulation of the right inferior pulmonary vein and the superior vena cava. By standardized procedural steps and techniques, petal-shaped PFA catheter significantly improves the success rate of ablation and reduces complications, offering a novel and effective approach to the treatment of atrial fibrillation.

心房颤动（简称房颤）是临床最常见的心律失常之一，严重影响患者的生活质量，并显著增加死亡、脑卒中、心力衰竭和痴呆的风险。射频消融已经成为最主要的房颤节律控制方法，但其疗效有个体差异性，且存在一定的严重并发症发生率、学习曲线长等不足。脉冲电场消融作为一种新型的房颤消融方式，通过短时程、高电压的电脉冲释放消融能量，以不可逆电穿孔机制消融心脏组织，具有组织特异性及安全性高、学习曲线短等优点。近日，哈特瑞姆心血管病医院采用Pentaspline多极脉冲电场消融导管，成功治疗了1例持续性房颤合并心包积液患者。术后1个月，患者心功能和生活质量均得到了显著改善。

Objective  To develop a transfer learning-based classification model for sleep apnea syndrome using electrocardiogram (ECG) data, increasing its classification accuracy and clinical applicability. Methods  Based on the Apnea-ECG and MIT-BIH polysomnographic databases, with respiratory signals as input, we applied a Butterworth low-pass filter for denoising, and constructed an original data set. To address the problem of insufficient respiratory signal data, a model training method based on a transfer learning approach was proposed: first, ECG signals with a large sample size were used for model pre-training, and then they were fine-tuning for respiratory signals, finally fulfilling binary classification or multi-class classification tasks. A cascade model combining residual network and bidirectional long short-term memory network was proposed, which performed better in capturing the timing features of signals and improving classification performance. Additionally, the performance of this model was made comparative analysis with those of various classic convolutional neural networks. Results  Through comparative experiments, it was found that employing transfer learning approach could accelerate model convergence and improve the model's overall performance. Validated on the test set, the proposed cascade model demonstrated a favorable performance in both binary classification and multi-class classification tasks, achieving an accuracy of 95.43% on the binary classification task and 91.26% on the multi-class classification task. Conclusion  This study offers novel insights into the design of disease classification models under small-sample conditions, and validates the effectiveness of transfer learning in sleep apnea syndrome classification, thereby demonstrating its potential clinical utility.

Pulsed field ablation (PFA) is a promising novel technique for arryhthmia ablation. It increases cell membrane permeability by irreversible electroporation mechanism, destructs intracellular homeostasis, and causes cell death. Meanwhile, due to its characteristics including high tissue specificity and nonthermal ablation, the application of PFA has been more and more attractive in the treatment of arrhythmias. This article reviews the mechanism, characteristics and progress on the clinical application of PFA in arrhythmias.

Objective  To investigate the correlation between ambulatory arterial stiffness index (AASI) and pulse pressure or blood pressure variability (BPV) in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods  A total of 205 patients specifically diagnosed with OSAHS were enrolled as research objects. They completed general data collection, and polysomnography and ambulatory blood pressure monitoring. Based on the classification of circadian blood pressure rhythm, the study population was divided into a dipper blood pressure group (n=92) and a nondipper blood pressure group (n=113). We compared the general clinical characteristics between the two groups as well as the correlation between AASI and ambulatory blood pressure parameters by using Pearson correlation analysis. Multiple linear regression analysis was applied to explore the relationship between AASI and pulse pressure or BPV. Results   The AASI of the non-dipper blood pressure group was significantly higher than that of the dipper blood pressure group (P<0.01). AASI was positively correlated with age, 24-hour mean systolic blood pressure and pulse pressure, while it was negatively correlated with 24-hour mean diastolic blood pressure, and the decline ratio of nocturnal systolic and diastolic blood pressure (all P<0.05). Pulse pressure was associated with AASI if BPV remained constant (P＜0.05). Conclusion  The AASI of OSAHS patients demonstrates an association with pulse pressure and age. AASI may serve as a promising indicator reflecting arterial stiffness.

Catheter ablation is a relatively effective method for maintaining sinus rhythm in patients with atrial fibrillation (AF). Pulsed field ablation (PFA) as a novel form of ablation energy exhibits tissue selectivity. Its efficacy in treating paroxysmal AF has been clinically demonstrated. However, the ablation of persistent AF is more complex and risky. Currently, the use of PFA for persistent AF is also gradually gaining traction. This article provides a review of the latest research progress on the efficacy, complications and its ablation strategies in the treatment of persistent AF.

Objective  To explore the association between obstructive sleep apnea syndrome (OSAS) and heart rate variability (HRV) or circadian rhythm of blood pressure in hypertensives. Methods  A total of 102 inpatients and outpatients with hypertension were selected in our study, and they were divided into hypertension with OSAS group (55 cases) and primary hypertension group (47 cases). This study enrolled 50 concurrent healthy subjects (all with organic diseases excluded, and without comorbidities of hypertension or OSAS) as a control group. We compared and analyzed the HRV time-domain indexes of SDANN and rMSSD, and HRV frequency-domain indexes of LF and HF, as well as apnea hypopnea index (AHI), nocturnal mean oxygen saturation level, daytime and nocturnal blood pressure levels, and changes of circadian blood pressure rhythm. Results  The nocturnal minimum saturation of arterial oxygen (SaO2) and nocturnal mean SaO2 of patients in the hypertension with OSAS group were both lower than those of patients in the primary hypertension group, while AHI was higher (all P＜0.05). There were no statistically significant differences in the above sleep respiratory parameters between the primary hypertension group and the control group (all P＞0.05). There were no statistically significant differences in the daytime and nocturnal blood pressure levels, and the incidence of non-dipper pattern between the primary hypertension group and the control group (all P＞0.05). Comparisons of the aforementioned parameters between the hypertension with OSAS group and the control group all demonstrated statistically significant differences (all P＜0.01). The hypertension with OSAS group exhibited a significantly higher prevalence of non-dipper circadian blood pressure rhythm compared to the other two groups (all P＜0.05). Compared to the other two groups, the values of SDANN and LF of patients in the hypertension with OSAS group were higher, while the values of rMSSD and HF were lower (all P＜0.05). There were no statistically significant differences in the LF, HF, SDANN and rMSSD values between the primary hypertension group and the control group (all P＞0.05). Conclusion  Patients with OSAS demonstrate increased nocturnal blood pressure level, enhanced sympathetic nerve tension and decreased vagus nerve tension, as well as increased risk of cardiovascular and cerebrovascular diseases.

Objective  To investigate the impact of long non-coding RNA ZFAS1 (lncZFAS1) on the initiation and progression of cardiomyocyte fibrosis. Methods  HL-1 mouse cardiac myocytes were induced by transforming growth factor-β (TGF-β) to establish a cardiomyocyte fibrosis model. LncZFAS1 overexpression vectors or small interfering RNA (siRNA) were transfected into the model. Protein levels of α-smooth muscle actin (α-SMA) and collagen Ⅰ were detected by western blotting; lncZFAS1 overexpression and interference fragments were transfected into the cardiomyocyte fibrotic model. The transcriptional level of lncZFAS1 was measured via real-time quantitative PCR. Cell proliferation viability was assessed using the CCK-8 assay, apoptosis rate was analyzed by flow cytometry, and LC3 autophagy puncta formation was examined using cellular immunofluorescence. Results  Compared with the control group, the TGF-β induction group showed significantly increased protein expression of α-SMA, collagen Ⅰ and LC3 B, significantly decreased p62 protein expression, elevated lncZFAS1 expression, enhanced cell viability and autophagy puncta formation, and reduced apoptosis rate (all P<0.05). After interfering with lncZFAS1 in the model, it showed a decrease in the expression level of lncZFAS1, a decrease in cell viability and the number of autophagy puncta, an increase of apoptosis rate and expression of p62 protein, and a decrease in the expression of LC3 B protein, all with statistically significant differences (all P<0.05). However, after overexpression of lncZFAS1, the opposite results were presented. Conclusion  LncZFAS1 promotes the initiation and progression of cardiomyocyte fibrosis by regulating cellular autophagy. Targeted inhibition of lncZFAS1 may provide a novel therapeutic strategy for delaying the progression of cardiovascular diseases.

Artificial intelligence (AI) has significantly improved the screening and diagnostic efficiency of ventricular arrhythmia (VA) through electrocardiogram (ECG) interpretation and wearable device monitoring. In the treatment field, AI has made significant progress in assisting the localization of premature ventricular contraction origins and optimizing strategies for implantable cardioverter defibrillator therapies. AI models excel in predicting the risk of fatal VA, providing robust support for individualized prevention and treatment. This review further discusses challenges such as data quality, model interpretability, and clinical translation, as well as the role of multimodal data integration and interdisciplinary collaboration in advancing the precision medicine for VA. In the future, AI is expected to play a more pivotal role in remote healthcare, and individualized diagnosis and treatment, comprehensively enhancing diagnostic accuracy, treatment efficiency, and quality of life for VA patients.

Pulsed field ablation (PFA) as an emerging ablation technology with characteristics of nonthermal mechanism and tissue selectivity could effectively reduce the damage to adjacent organs, and tissues (such as the esophagus, coronary arteries and phrenic nerve) caused by ablation. This article aims to discuss the application of PFA in atrial and ventricular arrhythmias, with a focus on its safety and effectiveness, and looks forward to its further application potential.

This article focuses on the application of artificial intelligence (AI) technology in the diagnosis and treatment of arrhythmias, and briefly introduces the latest relevant research findings from both domestic and international sources. It not only outlines the capability of AI in significantly improving the detection efficiency and accuracy of arrhythmia screening and diagnosis, but also emphasizes its value in the prediction of arrhythmia and the risk of its related complications, and guidance of its clinical treatment. Furthermore, this article summarizes the challenges faced by AI in arrhythmia management, including data quantity and quality issues, the “black box” effect in AI learning process, model generalization issues, ethical issues in technology, and the clinical acceptance of AI models. Finally, it looks forward to the prospect of AI technology deeply integrating with medicine, and comprehensive application in all aspects of arrhythmia diagnosis and treatment, so as to optimize medical resource allocation and medical service workflows, increase medical efficiency and quality, and improve patients’ prognoses.

Objective  To explore the relationship between epicardial fat thickness (EFT), serum secreted frizzled-related protein 5 (SFRP5), wingless-type MMTV integration site family member 5a (Wnt5a), and in-stent restenosis (ISR) in patients with acute ST-segment elevation myocardial infarction (STEMI) after percutaneous coronary intervention (PCI). MethodsA total of 128 STEMI patients who had undergone emergency PCI were enrolled. After a 12-month follow-up, they were divided into a non-ISR group (80 cases) and an ISR group (48 cases) based on coronary angiography results. The general data between the two groups were compared, as well as the EFT before discharge and 1 month after surgery, and the serum levels of SFRP5 and Wnt5a measured before surgery and 1 month postoperatively. The differences in the levels of these indicators among patients with varying degrees of coronary artery lesions were also examined. Pearson correlation analysis was used to evaluate the association between EFT and serum levels of SFRP5 and Wnt5a 1 month after surgery. Multivariate Logistic regression analysis was applied to identify the risk factors of ISR in STEMI patients after PCI. ROC curve analysis was used to assess the predictive value of EFT, and serum SFRP5 and Wnt5a levels for ISR. ResultsThe EFT values of the ISR group before discharge and 1 month after surgery were both greater than those of the non-ISR group (all P<0.01). The serum SFRP5 level of the ISR group was lower than that of the non-ISR group 1 month after surgery, while the serum Wnt5a level was higher (all P<0.01). Compared to pre-operative levels, serum SFRP5 levels increased 1 month after surgery in the non-ISR group but decreased in the ISR group (both P<005). Serum Wnt5a levels showed a mild increase 1 month after surgery compared to pre-operative levels in the non-ISR group, but increased significantly in the ISR group (both P<0.05). The serum SFRP5 level 1 month after surgery was significantly lower in the three-vessel disease group than that in the single- or two-vessel disease groups (P<0.05). EFT 1 month after surgery showed a negative correlation with SFRP5 and a positive correlation with Wnt5a. Both univariate Logistic regression analysis and Logistic regression analysis adjusted for factors such as age and BMI demonstrated that EFT, and serum SFRP5 and Wnt5a levels 1 month after surgery were independent influencing factors for ISR. ROC curve analysis revealed that the combination of these three markers yielded an AUC value of 0.906, which was higher than that of detection with any single indicator. Conclusion  Increased EFT, decreased serum SFRP5, and elevated serum Wnt5a 1 month after surgery are closely related to ISR in STEMI patients after PCI. Early detection of these markers facilitates the prediction of ISR, and the combined detection offers superior predictive value.

Objective  To investigate the regulatory role and underlying mechanism of circular RNA circHECTD1, a potential diagnostic biomarker for coronary heart disease (CHD), in macrophage polarization. Methods  A lipopolysaccharide-induced M1 macrophage polarization model was used to simulate a low-grade inflammatory response process. Quantitative real-time PCR (qRT-PCR) was employed to detect the expression levels of circHECTD1 and N6-methyladenosine (m6A) regulatory factors. Western blotting was performed to measure the expression of M1 phenotype marker proteins and autophagyrelated proteins. Intracellular reactive oxygen species (ROS) levels were assessed by flow cytometry. Results  Silencing circHECTD1 significantly reduced the expression of M1 phenotype-related proteins and inflammatory cytokines, decreased ROS levels, and enhanced cellular autophagy. Disordered expression of multiple m6A regulatory factors was observed in both the cellular model and peripheral blood mononuclear cells (PBMCs) from CHD patients. Significant differences in the expression levels of multiple m6A methylation regulators were identified between CHD and control groups, suggesting their potential value in CHD diagnosis. Univariate and multivariate Logistic regression analysis revealed that the m6A regulators of METTL3, METTL14, ALKBH5, and YTHDC2 were significantly associated with CHD risk. Further analysis showed that the expression of METTL14 and ALKBH5 were significantly upregulated in advanced stages of atherosclerosis. The expression level of circHECTD1 significantly correlated with FTO, YTHDF3, ALKBH5, METTL3, METTL14, and YTHDF2. In vitro experiment results demonstrated that silencing METTL14 and ALKBH5 markedly downregulated circHECTD1 expression, indicating that METTL14 and ALKBH5 positively regulated circHECTD1 expression. Conclusion  Dysregulation of m6A regulatory factors may be closely associated with the occurrence and development of CHD, potentially mediated through the regulation of circHECTD1 expression and function.

Objective  To investigate the application of dexmedetomidine via programmed intermittent epidural bolus (PIEB) for labor analgesia in hypertensive disorder of pregnancy (HDP) parturients, and its effect on umbilical artery flow and maternal-fetal outcomes. Methods  This study was a prospective, and double-blind clinical study. A hundred HDP parturients who had undergone labor analgesia were selected, and randomly divided into group A and B, each with 50 cases by random number table method. Group A received continuous epidural infusion, while group B received PIEB. Based on the visual analogue scale (VAS), the degree of pain before analgesia (T0), 1 h after analgesia (T1), 2 h after analgesia (T2), and at the time of complete cervical dilation (T3) were compared between the two groups of parturients. We simultaneously recorded the changes of umbilical artery flow at T0-T2 ［umbilical artery resistance index (RI), pulsation index (PI) and the ratio of maximum systolic blood velocity to diastolic blood velocity (S/D)］, maternal vital signs at T0 and T1 ［heart rate (HR) and mean arterial pressure (MAP)］, and the occurrence of adverse maternalfetal outcomes and adverse reactions in the two groups. ResultsComparison of VAS scores at different time points within each group showed statistically significant differences (all P<0.01). VAS scores at T1, T2 and T3 were all lower than that at T0(all P<0.05). VAS score of the group B at T2 was lower than that at T1(P<0.05). VAS score of the group B at T3 was lower than that at T2(P<0.05), while the VAS score of the group B at T2 or T3 were both lower than that of the group A (both P<0.01). There was no statistically significant difference in VAS score between the two groups at T0 and T1(P>0.05). Statistically significant differences were observed in RI, PI, and S/D values across different time points within both groups (all P<0.01). At T1 and T2, the RI, PI, and S/D ratio of fetuses in both groups all decreased compared to T0(all P<0.05). At T2, the RI, PI and S/D ratio of fetuses in both groups were all lower than those at T1(all P<0.05). There were no statistically significant differences in fetal RI, PI, and S/D ratio between the two groups at T0, T1 or T2(all P>0.05). At T1, HR and MAP in the two groups were both lower than those at T0(both P<0.05), while HR and MAP of the group B were both lower than those of the group A (both P<0.05). There were no statistically significant differences in the total incidences of adverse maternal-fetal outcomes or drug adverse reactions between the two groups (all P>0.05). Conclusion  Dexmedetomidine via PIEB could improve the effect of labor analgesia in HDP parturients, and maintain stability of fetal umbilical hemodynamics and maternal vital signs, with a high safety.

Continuous renal replacement therapy (CRRT) is an extracorporeal blood purification method used for critically ill patients with conditions such as acute kidney injury. The therapeutic effect of CRRT is influenced by the blood flow rate in the extracorporeal circuit. Low blood flow rate is significantly associated with circuit clotting and treatment interruption, while excessively high blood flow rate may lead to elevated circuit pressure, similarly impair therapeutic outcomes. At present, the optimal extracorporeal blood flow rate for CRRT remains unclear. Additionally, the special needs of different populations should be considered during the treatment, and how to set blood flow rate in various treatment scenarios is still an unresolved issue. This article provides a review of the current research status and future prospect of blood flow rate in CRRT, aiming to offer references for clinical practice and further research in this area.

Objective  To investigate the association between homocysteine (Hcy) and the C677T gene polymorphism in its key metabolic enzyme, methylenetetrahydrofolate reductase (MTHFR), and the complications of hypertension, type 2 diabetes mellitus and atherosclerosis in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods  A total of 85 OSAHS patients and 77 non-OSAHS patients were enrolled. The genotypes, and levels of serum Hcy, fasting blood glucose and hemoglobin Alc of all subjects were detected, while cervical vascular ultrasound was performed simultaneously. Hcy≥10 μmol/L was defined as hyperhomocysteinemia (HHcy). The serum Hcy levels were compared among patients with different genotypes. The Hcy levels, MTHFR C677T gene polymorphism, and C/T allele frequencies were compared among an OSAHS with complications group, a pure OSAHS group, and a control group (without OSAHS or complications). Then, multivariate binary Logistic regression analysis was performed to identify independent risk factors for complications in OSAHS patients with confounding factors adjusted. Results  The Hcy levels in the patients with CC, CT and TT genotypes were 10.11 (9.15, 11.07), 10.86 (9.58, 11.10) and 15.81 (11.43, 50.76) μmol/L, respectively. Hcy level in the patients with TT genotype was significantly higher than that in the cases with CT or CC genotypes (both P＜0.05). The Hcy levels of the OSAHS with complications group, the pure OSAHS group, and the control group were 11.16 (10.05, 13.80), 9.88 (9.31, 11.41), and 10.38 (9.29, 11.34) μmol/L, respectively. The Hcy level of the OSAHS with complications group was significantly higher than that of the pure OSAHS group (P<0.05). There were no statistically significant differences in gene polymorphism or C/T allele frequency among the three groups. After adjusting for confounding factors, it revealed that HHcy was an independent risk factor for concurrent complications in OSAHS patients, and the odds ratio (95% confidence interval) was 4.682 (1.261-17.380). Conclusion  The MTHFR C677T gene polymorphism affects serum Hcy level. HHcy is an independent risk factor for concurrent complications in OSAHS patients, however, neither the MTHFR C677T gene polymorphism nor the C/T allele frequency were associated with complications in OSAHS patients.

Objective  To investigate the long-term prognosis of renal dysfunction patients with fragmented QRS complex (fQRS). Methods  A total of 181 inpatients specifically diagnosed with renal dysfunction were selected as research objects. We collected their general information, laboratory test results, routine ECGs, readmissions, and mortality. They were divided into positive fQRS group (n=96) and negative fQRS group (n=85) based on the presence or absence of fQRS in the ECG. The cohort study method was used to compare the occurrence of readmission and death events between the two groups. ResultsThe readmission time of patients in the positive fQRS group was earlier than that in the negative fQRS group, and the difference was statistically significant (HR=2.486, P<0.01). The index of fQRS was an independent predictor of readmission in patients with renal dysfunction. There was no statistically significant difference in the time to death between the two groups (P=0.312). The estimated glomerular filtration rate and NT-proBNP were associated with the time to death (P=0.025 and 0.020, respectively). Conclusion  Renal dysfunction patients with fQRS are more likely to be readmitted. Patients with poorer renal function and elevated NT-proBNP levels demonstrate both higher mortality rates and accelerated time to death. Early screening of fQRS and related risk factors help to assess the prognosis of these patients.