Association of latent class analysis-derived subphenotypes of acute kidney injury with mortality in critically ill patients with cardiovascular disease: a retrospective cohort study.

BACKGROUND: To explore the potential heterogeneity of acute kidney injury (AKI) and evaluate the prognostic differences among AKI subphenotypes in critically ill patients with cardiovascular diseases. METHODS: Data were extracted from the Medical Information Mart for Intensive Care (MIMIC)-III database. Latent class analysis (LCA) was used to explore the potential subphenotypes of AKI in critically ill patients with cardiovascular diseases. The number of classes was identified by the Bayesian information criterion and entropy. The differences in prognostic ability among the AKI subphenotypes were evaluated by logistic regression analysis. RESULT: A total of 7738 AKI patients were enrolled in this study. Using LCA, AKI patients were divided into 4 heterogeneous subphenotypes, which were obviously different from the Kidney Disease: Improving Global Outcomes (KDIGO) stages. Interestingly, class 3 classified by LCA was dominated by stage 2, while the mortality rate in class 3 was significantly different from that in class 1 (15.2% vs. 1.6%, p < 0.05). After further adjustment, the mortality rate in class 3 remained higher than that in class 1, with an odds ratio of 12.31 (95% confidence interval, 8.96-16.89). CONCLUSIONS: LCA was feasible for AKI classification in critically ill patients with cardiovascular disease, and 4 distinct subphenotypes of AKI patients with different prognoses were identified. Our results highlighted the potential heterogeneity of AKI patients, which is worthy of further investigation.

Assessment of Cardiac Lead Perforation: Comparison Among Chest Radiography, Transthoracic Echocardiography and Electrocardiography-gated Contrast-enhanced Cardiac CT.

OBJECTIVES: Cardiac lead perforation is a rare but potentially life-threatening event. The purpose of this study was to investigate the diagnostic performances of chest radiography, transthoracic echocardiography (TTE) and electrocardiography (ECG)-gated contrast-enhanced cardiac CT in the assessment of cardiac lead perforation. METHODS: This retrospective study was approved by the ethics review board of Sun Yat-Sen Memorial Hospital at Sun Yat-Sen University (Guangzhou, China), and the need to obtain informed consent was waived. Between May 2010 and Oct 2017, 52 patients were clinically suspected to have a cardiac lead perforation and received chest radiography, TTE and ECG-gated contrast-enhanced cardiac CT. Among them, 13 patients were identified as having cardiac lead perforation. The diagnostic performances of these three modalities were evaluated by receiver-operating characteristic (ROC) curves using a composite reference standard of surgical and electrophysiological results and clinical follow-up. The areas under ROCs (AUROCs) were compared with the McNemar test. RESULTS: The accuracies of chest radiography, TTE and ECG-gated contrast-enhanced cardiac CT imaging for the diagnosis of cardiac lead perforation were 73.1%, 82.7% and 98.1%, respectively. ECG-gated contrast-enhanced cardiac CT had a higher AUROC than chest radiography (p < 0.001) and TTE (p < 0.001). CONCLUSIONS: ECG-gated contrast-enhanced cardiac CT is superior to both chest radiography and TTE imaging for the assessment of cardiac lead perforation. KEY POINTS: • ECG-gated contrast-enhanced cardiac CT has an accuracy of 98.1% in the diagnosis of cardiac lead perforation. • The AUROC of ECG-gated contrast-enhanced cardiac CT is higher than those of chest radiography and TTE imaging. • ECG-gated contrast-enhanced cardiac CT imaging has better diagnostic performance than both chest radiography and TTE imaging for the assessment of cardiac lead perforation.

Apelin promotes mesenchymal stem cells survival and vascularization under hypoxic-ischemic condition in vitro involving the upregulation of vascular endothelial growth factor.

BACKGROUND: Mesenchymal stem cells (MSCs) transplantation has been regarded as an optimal therapeutic approach for cardiovascular disease. However, the inferior survival and low vascularization potential of these cells in the local infarct site reduce the therapeutic efficacy. In this study, we investigated the influence of apelin on MSCs survival and vascularization under hypoxic-ischemic condition in vitro and explored the relevant mechanism. METHODS: MSCs were obtained from C57BL/6 mice and cultured in vitro. Cells of the third passage were divided into MSCs and MSCs+apelin groups. In the MSCs+apelin group, MSCs were stimulated with apelin-13 (5µM). The two groups experienced exposure to hypoxia (1% O2) and serum deprivation for 24h, using normoxia (20% O2) as a negative control during the process. Human umbilical vein endothelial cells (HUVECs) were used and incubated with conditioned media from both groups to promote vascularization for another 6h. Vascular densities were assessed and relevant biomarkers were detected thereafter. RESULTS: Compared with MSCs group, MSCs+apelin group presented more rapid growth. The proliferation rate was much higher. Cells apoptosis percentage was significantly declined both under normoxic and hypoxic conditions. Media produced from MSCs+apelin group triggered HUVECs to form a larger number of vascular branches on matrigel. The expression and secretion of vascular endothelial growth factor (VEGF) were significantly increased. CONCLUSION: Apelin could effectively promote MSCs survival and vascularization under hypoxic-ischemic condition in vitro, and this procedure was associated with the upregulation of VEGF. This study provides a new perspective for exploring novel approaches to enhance MSCs survival and vascularization potential.

Long noncoding RNAs: Novel molecules in cardiovascular biology, disease and regeneration.

Remarkable breakthroughs made in genomic technologies have facilitated the discovery of thousands of novel transcripts that do not template protein synthesis. Numerous RNAs termed as long noncoding RNAs (lncRNAs) generated from this pervasive transcription function vividly in gene regulatory networks and a variety of biological and cellular processes. Here, we make a brief description of the known and putative functions of lncRNAs in cardiovascular biology and disease. The association between lncRNAs and stem cells mediated cardiomyocytes differentiation and neovascularization is discussed then. It will provide a new clue for further studies on these novel molecules in cardiovascular disease and bring bright prospects for their future applications in cardiac regenerative medicine.

Cardiac stem cells transplantation enhances the expression of connexin 43 via the ANG II/AT1R/TGF-beta1 signaling pathway in a rat model of myocardial infarction.

BACKGROUND: In this study, we hypothesized that CSCs mediated the expression of Cx43 after transplantation post MI via the ANG II/AT1R/TGF-beta1 signaling pathway. METHODS: Myocardial infarction (MI) was induced in twenty male Sprague-Dawley rats. The rats were randomized into two groups and were then received the injection of 5 × 10(6) CSCs labeled with PKH26 in phosphate buffer solution (PBS) or equal PBS alone into the infarct anterior ventricular free wall two weeks after MI. Six weeks later, relevant signaling molecules involved were all examined. RESULTS: In the CSCs group, an increased expression of Cx43 could be observed in different zones of the left ventricle (P<0.01). There was a significant reduction of the angiotensin II (ANG II) level in plasma and different regions of the left ventricular cardiac tissues (P<0.05; P<0.01). The angiotensin II type I receptor (AT1R) was decreased accompanied with an enhanced expression of angiotensin II type II receptor (AT2R) (P<0.01). Transforming growth factor beta-1(TGF-beta1) was downregulated (P<0.01). The expression of mothers against decapentaplegic homolog (SMAD) proteins including SMAD2 and SMAD3 was attenuated whereas SMAD7 was elevated (P<0.01, P<0.01, P<0.05). In addition, the expression of mitogen-activated protein kinases (MAPKs) including extracellular kinases 1/2 (ERK1/2) and p38 was also found to be reduced (P<0.01). CONCLUSION: CSCs transplantation could enhance the level of Cx43 after MI. They might function through intervening the ANGII/AT1R/TGF-beta1 signaling pathway to regulate the expression of Cx43.

Investigating the clinical utility of global and regional myocardial work parameters in predicting response to cardiac resynchronization therapy in patients with heart failure and reduced ejection fraction.

Background: Previous studies have indicated that despite adhering to current patient selection guidelines, there remains a 30% to 40% subset of patients who do not experience improvement in heart failure (HF) after receiving cardiac resynchronization therapy (CRT). We aim to utilize echocardiographic myocardial work parameters to serve as predictors of responsiveness to CRT in patients with heart failure and reduced ejection fraction (HFrEF). Methods: We prospectively recruited patients who underwent CRT at Sun Yat-sen Memorial Hospital from June 2019 to September 2022. Comprehensive preoperative information, clinical laboratory data, conventional echocardiographic parameters and myocardial work were collected for all participants, as well as follow-up data 6 months after CRT. Results: Twenty-five patients (67.6%) showed response to CRT treatment, while twelve patients (32.4%) had no response. Compared with the non-response group, the response group had larger region constructive work [RCW: the sum of constructive work (CW) in the 9 segments of the basal, mid, and apical segments of the anterior, lateral, and posterior walls], region wasted work [RWW: the sum of wasted work (WW) in the 6 segments of the basal and mid segments of the anterior septum, posterior septum and anterior walls], and the combination of RCW and RWW (RCW + RWW) in baseline (RCW: 9,695.68±2,955.40 vs. 5,219.50±2,207.68 mmHg%, P<0.001; RWW: 3,612.08±1,723.80 vs. 1,674.33±995.23 mmHg%, P=0.001; RCW + RWW: 13,307.76±3,857.71 vs. 6,893.83±2,592.83 mmHg%, P<0.001). Furthermore, global constructive work (GCW), global wasted work (GWW), GCW + GWW, RCW, RWW, and RCW + RWW had areas under the receiver operating characteristic curve (AUCs) of 0.870, 0.770, 0.860, 0.890, 0.870, and 0.910, respectively, for predicting CRT responsiveness. Conclusions: The global and regional myocardial work parameters are associated with CRT response in CRT candidates. Particularly regional myocardial work parameters appear to be promising parameters to improve selection for CRT of patients with HFrEF.

N-terminal pro-B-type natriuretic peptide, eGFR, and progression of kidney disease in chronic kidney disease patients without heart failure.

Background: Cardiorenal syndrome highlights the bidirectional relationship between kidney and heart dysfunction. N-terminal pro-B-type natriuretic peptide (NT-proBNP), which is the gold standard biomarker in heart failure (HF), may be an important biomarker for chronic kidney disease (CKD) progression. However, NT-proBNP is negatively related with estimated glomerular filtration rate (eGFR). In this study, we investigated the association of NT-proBNP, eGFR, and progression of kidney disease in CKD patients without HF. Methods: This multicentric retrospective cohort study recruited 23 860 CKD patients without HF, who had at least one NT-proBNP record from China Renal Data System database. Linear regression model evaluated the relationship between eGFR and NT-proBNP. Cox regression analysis assessed the association between NT-proBNP and CKD progression. Sensitivity analysis examined the robustness of the main findings. Results: This study involved 23 860 CKD patients without HF, distributed across different CKD stages: 10 526 in stages G1-2, 4665 in G3a, 3702 in G3b, 2704 in G4, and 2263 in G5. NT-proBNP was negatively correlated with eGFR, particularly in stages 4-5 CKD. A 15-unit decrease in eGFR was associated with increases in log (NT-proBNP) levels by 1.04-fold, 1.27-fold, 1.29-fold, 1.80-fold, and 3.50-fold for stages 1-2, 3a, 3b, 4, and 5, respectively. After excluding patients who developed CKD progression within 1 year, the Cox regression analysis revealed that the relationship between NT-proBNP and CKD progression was not significant in stages 4 and 5. However, for stages 1-3, each standard deviation increase in log (NT-proBNP) was associated with a 26%, 36%, and 28% higher risk of CKD progression, with P interaction ≤.001. The hazard ratios were 1.26 (95% confidence intervals (CI), 1.18 to 1.35), 1.36 (95% CI, 1.22 to 1.51), and 1.28 (95% CI, 1.14 to 1.43) for stages 1-2, stage 3a, and stage 3b, respectively. Conclusions: Despite its strong inverse association with eGFR, NT-proBNP was positively associated with the risk of progression of kidney disease in CKD patients with stages 1-3 without HF. Future studies should investigate the effectiveness of NT-proBNP as a predictive biomarker for the progression of kidney disease across diverse racial groups and healthcare settings.

Study on the relationship between atrial high-rate episode and left atrial strain in patients with cardiac implantable electronic device.

Background: Although atrial high-rate episode (AHRE) and atrial fibrillation (AF) cannot entirely be identical, recent studies suggest AHRE is linked to AF development and shares some characteristics with AF regarding thromboembolism. At present, there is still lack of predictive indicators for AHRE and diagnostic methods and clinical indicators for AHRE in patients without cardiac implantable electronic device (CIED). The aim of this study was thus to explore the relationship between AHRE and left atrial (LA) strain parameters with the goal of identifying high-risk populations of AHRE by LA strain characteristics. Methods: From February 2022 to May 2023, a total of 105 CIED patients were enrolled and divided into two groups based on whether AHRE had occurred: AHRE (-) group (n=65) and AHRE (+) group (n=40). Real-time three-dimensional echocardiography (RT-3DE) technique was used to obtain the LA time-volume curve. The collected dynamic images were analyzed on the Echopac 204 workstation to obtain the parameters of LA. The four-dimensional automatic LA quantitative analysis (4D Auto LAQ) technology was used to analyze the LA strain parameters: LA reservoir longitudinal strain (LASr), LA conduit longitudinal strain (LAScd), LA contraction longitudinal strain (LASct), LA reservoir circumferential strain (LASr-c), LA conduit circumferential strain (LAScd-c), LA contraction circumferential strain (LASct-c). Correlation analysis was carried out using Binary logistic regression analysis. The area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the diagnostic performance of LASct in AHRE. Results: Body surface area (BSA) [odds ratio (OR) =8.34, 95% confidence interval (CI): 1.32-72.30, P=0.037], LASct (OR =1.20, 95% CI: 1.05-1.39, P=0.013) and LA end-systolic volume (LAESV) (OR =1.02, 95% CI: 1.00-1.04, P=0.023) were the influencing factors of AHRE. Only LASct (OR =1.18, 95% CI: 1.01-1.38, P=0.041) was found to be an independent influencing factor of AHRE. This result remained significant after adjusting for age, sex, hypertension, diabetes, and stroke history. The ROC curve showed that the cut-off for predicting AHRE was LASct =-4.125% with sensitivity of 37.5% and specificity of 87.7%. Conclusions: This cross-sectional study found that decreased LASct (absolute value) is an independent risk factor for the AHRE and has diagnostic efficacy in certain degree for the occurrence of AHRE.

Radiofrequency catheter ablation for improving myocardial work in patients with ventricular pre-excitation.

Background: Previous studies have not consistently found significant improvements in left ventricular ejection fraction or global longitudinal strain (GLS) after radiofrequency catheter ablation (RFCA) in patients with ventricular pre-excitation. The aim of this study was thus to explore the effects of RFCA on left ventricular function in patients with ventricular pre-excitation using a new noninvasive echocardiographic method of myocardial work. Methods: A total of 34 patients with ventricular pre-excitation who underwent RFCA and 18 healthy controls were prospectively included in this study. Before and after participants underwent RFCA, electrocardiographic and echocardiographic data of the patients were collected at resting and pacing heart rates (HRs) of 100 beats per minute (bpm) and 120 bpm (controlled by high right atrial pacing during the procedure). Clinical data of the healthy controls at resting HR were also collected. A self-controlled paired sample t test was used to compare the differences before and after participants underwent RFCA. Results: After participants underwent RFCA, the global wasted work (GWW) of the included patients decreased (resting HR: 165.3±68.8 vs. 92.6±42.5 mmHg%, P<0.001; HR of 100 bpm: 276.3±121.2 vs. 187.9±96.0 mmHg%, P<0.001; HR of 120 bpm: 323.9±126.7 vs. 181.0%±74.3 mmHg%. P<0.001), while the global work efficiency (GWE) increased (resting HR: 91.5%±3.8% vs. 94.9%±1.6%; P<0.001; HR of 100 bpm: 87.0%±5.2% vs. 91.0%±3.3%, P<0.001; HR of 120 bpm: 85.0%±5.1% vs. 90.3%±3.7%, P<0.001). Conclusions: In patients with ventricular pre-excitation, impaired GWW and GWE can be improved with RFCA. In clinical practice, noninvasive myocardial work assessment can be used in patients with ventricular pre-excitation.

How the trabeculae protrude within the left atrial appendage is the key factor affecting thrombosis in patients with atrial fibrillation.

The left atrial appendage (LAA) is a major site of thrombosis in patients with non-valvular atrial fibrillation. The myocardial trabeculae within the LAA have a peculiar tendency to protrude but its relationship to thrombosis remains unknown. This study aimed to investigate the relationship between the condition of trabeculae protrusion and LAA thrombosis. This retrospective study consecutively selected patients diagnosed with non-valvular atrial fibrillation and prepared for radiofrequency ablation from January 2011 to May 2020. Patients were divided into the thrombus group (n = 43), the sludge group (n = 35), and the normal group (n = 407) according to whether the thrombus or sludge was present. The trabeculae protruding angle (TPA), which was measured by the CT scans, was used to quantify the trabeculae protrusion condition. Patients' clinical data, TPA, LAA emptying velocity, and other factors were collected and compared among the three groups. A total of 485 patients were enrolled. The range of TPA was between 0 and 158 degrees, with an average of 89.3 ± 35.6 degrees. The TPA was significantly greater in the thrombus (109.3 ± 14.8 degrees) and sludge groups (110.8 ± 12.8 degrees) than in the normal group (85.3 ± 37.1). The incidence of LAA thrombus and sludge increased with increasing TPA. Multivariate regression analysis showed that the TPA was an independent risk factor for LAA thrombus (OR = 1.046, 95%CI: 1.020-1.073, p < 0.001) and sludge (OR = 1.035, 95%CI: 1.017-1.053, p < 0.001). Further analysis revealed that the TPA was negatively correlated with LAA emptying velocity but its effect on promoting thrombosis was not only mediated by slowing down the flow velocity. The TPA can well reflect the condition of trabeculae protrusion. This study revealed that the TPA was an independent risk factor for LAA thrombus or sludge, providing a potential indicator for future thrombosis risk assessment.

Left bundle branch pacing on mechanical synchrony and myocardial work in bradycardia patients.

Left bundle branch pacing (LBBP) has emerged as a novel physiological pacing method to produce narrower QRS duration, but whether it could restore mechanical synchrony and improve myocardial work still lacks sufficient evidence. Therefore, the goal of this study was to evaluate mechanical synchrony and myocardial work in LBBP. We collected 20 patients with LBBP due to symptomatic bradycardia and another 29 age-matched patients with right ventricular pacing (RVP). For LBBP patients, cardiac electro-mechanical synchrony and myocardial work were measured at baseline and 7 days after implantation and compared with the RVP patients. In the LBBP group, paced QRS duration and mechanical synchrony were not significantly different from baseline(all P > 0.05), but significantly smaller than that in the RVP group (all P<0.05). Meanwhile, global longitudinal strain (GLS) in LBBP was greater than that in the RVP group (17.7 ± 3.5% vs. 14.8 ± 3.1%, P < 0.05). Global myocardial work index and global constructive work were also better than that in the RVP group(all P<0.05). Global work efficiency was 91.9 ± 3.1%, which was greater when compared with RVP (P < 0.05). LBBP provides better cardiac electro-mechanical synchrony and more effective myocardial work than that in RVP, thus improving global heart function.

Bone marrow mesenchymal stem cells for post-myocardial infarction cardiac repair: microRNAs as novel regulators.

Transplantation of bone marrow-derived mesenchymal stem cells (MSCs) is safe and may improve cardiac function and structural remodelling in patients following myocardial infarction (MI). Cardiovascular cell differentiation and paracrine effects to promote endogenous cardiac regeneration, neovascularization, anti-inflammation, anti-apoptosis, anti-remodelling and cardiac contractility, may contribute to MSC-based cardiac repair following MI. However, current evidence indicates that the efficacy of MSC transplantation was unsatisfactory, due to the poor viability and massive death of the engrafted MSCs in the infarcted myocardium. MicroRNAs are short endogenous, conserved, non-coding RNAs and important regulators involved in numerous facets of cardiac pathophysiologic processes. There is an obvious involvement of microRNAs in almost every facet of putative repair mechanisms of MSC-based therapy in MI, such as stem cell differentiation, neovascularization, apoptosis, cardiac remodelling, cardiac contractility and arrhythmias, and others. It is proposed that therapeutic modulation of individual cardiovascular microRNA of MSCs, either mimicking or antagonizing microRNA actions, will hopefully enhance MSC therapeutic efficacy. In addition, MSCs may be manipulated to enhance functional microRNA expression or to inhibit aberrant microRNA levels in a paracrine manner. We hypothesize that microRNAs may be used as novel regulators in MSC-based therapy in MI and MSC transplantation by microRNA regulation may represent promising therapeutic strategy for MI patients in the future.

Effect of amiodarone on dispersion of ventricular repolarization in a canine congestive heart failure model.

The effects of amiodarone on ventricular electrophysiological parameters, especially the dispersion of ventricular repolarization, were investigated in a canine model of congestive heart failure (CHF). Dogs were randomized to either a control, amiodarone, CHF, or CHF+amiodarone group. Dogs in the CHF and CHF+amiodarone groups underwent 4-5 weeks of rapid ventricular pacing; dogs in the control and amiodarone groups underwent sham operation only. Amiodarone (20 mg/kg per day) was administered orally, beginning on postoperative Day 1, in the treatment groups; ventricular electrophysiological variables were evaluated 4-5 weeks after rapid pacing or sham operation. In CHF dogs, the transmural dispersion ventricular repolarization time (TDVRT) increased significantly. Amiodarone significantly decreased the TDVRT in CHF dogs. The ventricular fibrillation threshold (VFT) decreased in the CHF group. Amiodarone increased the VFT in CHF dogs. The TDVRT increased in CHF dogs, but amiodarone decreased TDVRT and increased VFT in these dogs. These results suggest a beneficial effect of amiodarone on malignant arrhythmias and may provide the basis for its use in CHF patients.

Changes in echocardiographic parameters of the donor's heart before and after heart transplantation and their relationship with post-transplant survival.

Background: Heart transplantation is now widely performed in China, but the current entry criteria for heart transplantation donors are simple and lack reliable standards; there are still no studies on the effect of preoperative echocardiographic parameters of heart transplantation donors on the prognosis of the recipient. Therefore, the aim of this study is twofold: (I) to observe the characteristics of changes in echocardiographic parameters of the donor's heart before and after heart transplantation and (II) to study the relationship between the changes in echocardiographic parameters of the donor's heart pre- and post-transplant and transplant recipient survival. Methods: A total of 29 patients who underwent orthotopic heart transplant in our hospital from October 2016 to October 2019 were enrolled in this study. All recipients were followed up until April 2020. Echocardiographic data were collected pre-transplantation (donor) and at 1 week and 1 month post-transplant (recipient). Results: Compared with the pretransplanted donor's heart, there was an increase in the interventricular septal diameter, left ventricular posterior wall diameter, right atrium diameter and right ventricular diameter, while a decrease was found in the tricuspid annular systolic displacement and tricuspid annular peak systolic velocity at 1 week post-transplant. The survival curve showed that the postoperative survival time in the right atrium/ventricle ≥32 mm group was better than that in the right atrium/ventricle <32 mm group. The survival curve also showed that the postoperative survival time in the right atrium/ventricle enlargement <2 mm group was better than that in the right atrium/ventricle enlargement ≥2 mm group. Conclusions: In the early post-transplant period, ventricular myocardial thickening, right heart enlargement and a decrease in right heart function were observed in the post-transplanted heart compared to the pretransplanted donor's heart. Postoperative survival was higher among heart transplant patients who received a heart with right atrium/ventricle ≥32 mm. Postoperative survival was lower among heart transplant patients whose right atrium/ventricle was dilated ≥2 mm at 1 month postoperatively compared with the pretransplanted donor's heart.

Repair mechanisms of bone marrow mesenchymal stem cells in myocardial infarction.

The prognosis of patients with myocardial infarction (MI) and resultant chronic heart failure remains extremely poor despite advances in optimal medical therapy and interventional procedures. Animal experiments and clinical trials using adult stem cell therapy following MI have shown a global improvement of myocardial function. Bone marrow-derived mesenchymal stem cells (MSCs) hold promise for cardiac repair following MI, due to their multilineage, self-renewal and proliferation potential. In addition, MSCs can be easily isolated, expanded in culture, and have immunoprivileged properties to the host tissue. Experimental studies and clinical trials have revealed that MSCs not only differentiate into cardiomyocytes and vascular cells, but also secrete amounts of growth factors and cytokines which may mediate endogenous regeneration via activation of resident cardiac stem cells and other stem cells, as well as induce neovascularization, anti-inflammation, anti-apoptosis, anti-remodelling and cardiac contractility in a paracrine manner. It has also been postulated that the anti-arrhythmic and cardiac nerve sprouting potential of MSCs may contribute to their beneficial effects in cardiac repair. Most molecular and cellular mechanisms involved in the MSC-based therapy after MI are still unclear at present. This article reviews the potential repair mechanisms of MSCs in the setting of MI.

Improvements of cardiac electrophysiologic stability and ventricular fibrillation threshold in rats with myocardial infarction treated with cardiac stem cells.

OBJECTIVES: Arrhythmia is of concern after cardiac stem cell transplantation in repairing infarcted myocardium. However, whether transplantation improved the ventricular fibrillation threshold and whether severe malignant ventricular arrhythmia is induced in the myocardial infarction model are still unclear. We sought to investigate the electrophysiologic characteristics and ventricular fibrillation threshold in rats with myocardial infarction by treatment with allogeneic cardiac stem cells. DESIGN: Prospective, randomized, controlled study. SETTING: University-affiliated hospital. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Myocardial infarction was induced in 20 male Sprague-Dawley rats. Two weeks later, animals were randomized to receive 5 × 10(6) cardiac stem cells labeled with PKH26 in phosphate buffer solution or a phosphate buffer solution-alone injection into the infarcted anterior ventricular-free wall. MEASUREMENTS AND MAIN RESULTS: Six weeks after the cardiac stem cell or phosphate buffer solution injection, electrophysiologic characteristics and ventricular fibrillation threshold were measured at the infarct area, infarct marginal zone, and noninfarct zone. Labeled cardiac stem cells were observed in 5-µm cryostat sections from each harvested heart. The unipolar electrogram activation recovery time dispersions were shorter in the cardiac stem cell group compared with those at the phosphate buffer solution group (15.5 ± 4.4 vs. 38.6 ± 14.9 msecs, p = .000177). Malignant ventricular arrhythmias were significantly (p = .00108) less inducible in the cardiac stem cell group (one of ten) than the phosphate buffer solution group (nine of ten). The ventricular fibrillation thresholds were greatly improved in the cardiac stem cell group compared with the phosphate buffer solution group. Labeled cardiac stem cells were identified in the infarct zone and infarct marginal zone and expressed Connexin-43, von Willebrand factor, α-smooth muscle actin, and α-sarcomeric actin. CONCLUSIONS: Cardiac stem cells may modulate the electrophysiologic abnormality and improve the ventricular fibrillation threshold in rats with myocardial infarction treated with allogeneic cardiac stem cells and cardiac stem cell express markers that suggest muscle, endothelium, and vascular smooth muscle phenotypes in vivo.

Klotho gene improves oxidative stress injury after myocardial infarction.

The aim of the present study was to investigate the effects and mechanisms of the Klotho gene in oxidative stress injury after myocardial infarction. Sprague-Dawley rats were divided into five groups (sham, model, pDC316, LY294002, and pDC316-Klotho). Subsequently, the superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) concentrations were measured in myocardial tissues. Additionally, pathological differences among the groups were evaluated using hematoxylin and eosin and Masson's trichrome staining. Apoptosis was assayed by terminal deoxynucleotidyl transferase 2'-deoxyuridine-5'-triphosphate nick end-labeling assay, evaluated Klotho protein expression by immunohistochemical assay, and assessed Nrf 2 and ARE protein expressions using western blotting assay. As compared with in the sham group, the SOD, MDA, and GSH concentrations were significantly deteriorated (P<0.001, respectively); cardiomyocyte apoptosis index values were significantly increased (P<0.001); Klotho protein expression was significantly depressed; and Nrf-2 and ARE protein expressions were significantly (P<0.001, respectively) in the model and pDC316 groups. However, with Klotho supplementation by pDC316 transfection, as compared with in the model group, the SOD, MDA, and GSH concentrations were significantly improved (P<0.001, respectively); the cardiomyocyte apoptosis index values were significantly suppressed (P<0.001); and the pathology was improved. Further, the Klotho protein expression of the pDC316-Klotho group was significantly upregulated and the Nrf-2 and ARE proteins expressions of the LY294002 and pDC316-Klotho groups were significantly suppressed. Klotho overexpression improved findings of oxidative stress injury after myocardial infarction.

Mental health is correlated with lipoprotein(a) levels in male patients with premature coronary heart disease.

BACKGROUND: High levels of lipoprotein(a) (Lp(a)) is an independent risk factor for premature coronary heart disease (PCHD). It is also considered a residual risk for controlled low density lipoprotein cholesterol (LDL-C). Dietary control, exercise, and drugs have limited effects on the levels of Lp(a). Recently, mental health was found to be associated with lipid levels and increased risk of PCHD. However, the relationship between mental health and Lp(a) is still unknown. This study explored the association between mental health and Lp(a) levels in men with PCHD. METHODS: A retrospective, observational study was conducted. A total of 226 male patients with PCHD, aged 49.65±3.68 years, was included in this study. The control group consisted of 230 age-matched healthy male volunteers. Serum Lp(a) levels ≥30 mg/dL, as measured by the immunoturbidimetry method, were considered high. All participants received health related quality of life (HRQoL) scores using the self-assessed 36-Item Short Form Health Survey (SF-36). The HRQoL includes both a physical component summary (PCS) and a mental component summary (MCS). RESULTS: Patients with PCHD were found to have higher levels of Lp(a) (51.61±33.39 vs. 26.42±21.93, P<0.001), and lower MCS (35.83±4.21 vs. 39.85±4.12) and PCS scores (38.02±3.73 vs. 39.63±3.21) compared to healthy volunteers. The MCS score was negatively correlated with Lp(a) levels in the PCHD group (R=-0.295, P<0.001), but no correlation was detected in the control group. There was no relationship between the PCS score and Lp(a) levels in neither the PCHD group nor the healthy control group. Multivariate logistic regression analysis indicated that the MCS and PCS scores were negatively correlated with the risk of PCHD. CONCLUSIONS: These findings suggested that poor mental health may be associated with high levels of Lp(a) and increased risk of PCHD in men. Therefore, improving the mental state in men with PCHD may be crucial.

3D transesophageal echocardiography assists in evaluating the morphology, function, and presence of thrombi of left atrial appendage in patients with atrial fibrillation.

BACKGROUND: Left atrial appendage (LAA) is significantly more likely to form thrombi in patients with atrial fibrillation (AFib). Two-dimensional transesophageal echocardiography (2D TEE) is considered the gold standard for assessing and studying LAA morphology and anatomy. However, 2D TEE can only visualize one plane at any given time. Real-time three-dimensional echocardiography (RT-3D TEE) imaging can preserve spatial and temporal resolution, which is a safe, accurate, and reproducible imaging modality. There are few reports of the usage of RT-3D TEE to study LAA in AFib patients. In our research, RT-3D TEE helps to provide detailed LAA information and identifying the presence or absence of thrombi from pectinate muscles in paroxysmal and long-standing AFib patients. METHODS: LAA morphology was analyzed in detail by 2D TEE and RT-3D TEE in 320 patients with paroxysmal or long-standing AFib. The LAA flow pattern, as maximal LAA emptying flow velocity (LAAeV), was retrieved from 2D and 3D TEE imaging. LAA morphological parameters, spontaneous echo contrast (SEC), and thrombi were also detected by 2D and 3D TEE in all patients. In addition, LAA lobes and types were classified according to the morphology by 3D TEE, and the relationship between LAA types and the incidence of thrombi was evaluated. RESULTS: Long-standing AFib had greater enlargement of LAAs (orifice diameters and area), significantly more severe SEC, and a higher thrombi clot incidence rate by 3D-TEE compared with paroxysmal AFib patients (P<0.05). In addition, cauliflower morphology in long-standing AFib patients was associated with a higher LAA thrombus (OR 2.1, 95% CI: 1.1-8.5, P=0.031) and increased prevalence of SEC. Moreover, the uncertainty of thrombi detection was significantly decreased by 3D TEE compared with 2D TEE (P<0.001), and the certainty of thrombi detection by 3D TEE also decreased slightly (P=0.06). CONCLUSIONS: RT-3D TEE is a safe and real-time option for the evaluation of LAA morphology and function. Long-standing AFib has greater LAA and SEC, as well as a higher incidence of thrombi than the paroxysmal group. Cauliflower LAA type was associated with a higher prevalence of SEC and thrombi.

Mechanical Synchrony and Myocardial Work in Heart Failure Patients With Left Bundle Branch Area Pacing and Comparison With Biventricular Pacing.

Background: Little is known about the efficacy of permanent left bundle branch area pacing (LBBAP) in delivering cardiac resynchronization therapy (CRT). This study aimed to evaluate the effect of LBBAP on mechanical synchronization and myocardial work (MW) in heart failure (HF) patients and to compare LBBAP with biventricular pacing (BVP). Methods: This is a multicenter, prospective cohort study. From February 2018 to January 2021, 62 consecutive HF patients with reduced ejection fraction (LVEF ≤ 35%) and complete left bundle branch block (CLBBB) who underwent LBBAP or BVP were enrolled in this study. Echocardiograms and electrocardiograms and were conducted before and 3-6 months after implantation. Intra- and interventricular synchronization were assessed using two-dimensional speckle tracking imaging (2D-STI). The left ventricular pressure-strain loop was obtained by combining left ventricular strain with non-invasive blood pressure to evaluate mechanical efficiency. Results: The echocardiographic response rates were 68.6 and 88.9% in the BVP and LBBAP groups, respectively. Left bundle branch area pacing resulted in significant QRS narrowing (from 177.1 ± 16.7 to 113.0 ± 18.4 ms, P < 0.001) and improvement in LVEF (from 29.9 ± 4.8 to 47.1 ± 8.3%, P < 0.001). The global wasted work (GWW) (410.3 ± 166.6 vs. 283.0 ± 129.6 mmHg%, P = 0.001) and global work efficiency (GWE) (64.6 ± 7.8 vs. 80.5 ± 5.7%, P < 0.001) were significantly improved along with shorter peak strain dispersion (PSD) (143.4 ± 45.2 vs. 92.6 ± 35.1 ms, P < 0.001) and interventricular mechanical delay (IVMD) (56.4 ± 28.5 vs. 28.9 ± 19.0 ms, P < 0.001), indicating its efficiency in improving mechanical synchronization. In comparison with BVP, LBBAP delivered greater improvement of QRS narrowing (-64.1 ± 18.9 vs. -32.5 ± 22.3 ms, P < 0.001) and better mechanical synchronization and efficiency. Conclusions: Left bundle branch area pacing was effective in improving cardiac function, mechanical synchronization, and mechanical efficiency and may be a promising alternative cardiac resynchronization therapy.