Inhibition of IL-1 Ameliorates Cardiac Dysfunction and Arrhythmias in a Murine Model of Kawasaki Disease.

BACKGROUND: Kawasaki disease (KD) is an acute febrile illness and systemic vasculitis often associated with cardiac sequelae, including arrhythmias. Abundant evidence indicates a central role for IL (interleukin)-1 and TNFα (tumor necrosis factor-alpha) signaling in the formation of arterial lesions in KD. We aimed to investigate the mechanisms underlying the development of electrophysiological abnormalities in a murine model of KD vasculitis. METHODS: Lactobacillus casei cell wall extract-induced KD vasculitis model was used to investigate the therapeutic efficacy of clinically relevant IL-1Ra (IL-1 receptor antagonist) and TNFα neutralization. Echocardiography, in vivo electrophysiology, whole-heart optical mapping, and imaging were performed. RESULTS: KD vasculitis was associated with impaired ejection fraction, increased ventricular tachycardia, prolonged repolarization, and slowed conduction velocity. Since our transcriptomic analysis of human patients showed elevated levels of both IL-1ß and TNFα, we asked whether either cytokine was linked to the development of myocardial dysfunction. Remarkably, only inhibition of IL-1 signaling by IL-1Ra but not TNFα neutralization was able to prevent changes in ejection fraction and arrhythmias, whereas both IL-1Ra and TNFα neutralization significantly improved vasculitis and heart vessel inflammation. The treatment of L casei cell wall extract-injected mice with IL-1Ra also restored conduction velocity and improved the organization of Cx43 (connexin 43) at the intercalated disk. In contrast, in mice with gain of function of the IL-1 signaling pathway, L casei cell wall extract induced spontaneous ventricular tachycardia and premature deaths. CONCLUSIONS: Our results characterize the electrophysiological abnormalities associated with L casei cell wall extract-induced KD and show that IL-1Ra is more effective in preventing KD-induced myocardial dysfunction and arrhythmias than anti-TNFα therapy. These findings support the advancement of clinical trials using IL-1Ra in patients with KD.

Mechanisms of Sinoatrial Node Dysfunction in Heart Failure With Preserved Ejection Fraction.

BACKGROUND: The ability to increase heart rate during exercise and other stressors is a key homeostatic feature of the sinoatrial node (SAN). When the physiological heart rate response is blunted, chronotropic incompetence limits exercise capacity, a common problem in patients with heart failure with preserved ejection fraction (HFpEF). Despite its clinical relevance, the mechanisms of chronotropic incompetence remain unknown. METHODS: Dahl salt-sensitive rats fed a high-salt diet and C57Bl6 mice fed a high-fat diet and an inhibitor of constitutive nitric oxide synthase (Nω-nitro-L-arginine methyl ester [L-NAME]; 2-hit) were used as models of HFpEF. Myocardial infarction was created to induce HF with reduced ejection fraction. Rats and mice fed with a normal diet or those that had a sham surgery served as respective controls. A comprehensive characterization of SAN function and chronotropic response was conducted by in vivo, ex vivo, and single-cell electrophysiologic studies. RNA sequencing of SAN was performed to identify transcriptomic changes. Computational modeling of biophysically-detailed human HFpEF SAN was created. RESULTS: Rats with phenotypically-verified HFpEF exhibited limited chronotropic response associated with intrinsic SAN dysfunction, including impaired ß-adrenergic responsiveness and an alternating leading pacemaker within the SAN. Prolonged SAN recovery time and reduced SAN sensitivity to isoproterenol were confirmed in the 2-hit mouse model. Adenosine challenge unmasked conduction blocks within the SAN, which were associated with structural remodeling. Chronotropic incompetence and SAN dysfunction were also found in rats with HF with reduced ejection fraction. Single-cell studies and transcriptomic profiling revealed HFpEF-related alterations in both the "membrane clock" (ion channels) and the "Ca2+ clock" (spontaneous Ca2+ release events). The physiologic impairments were reproduced in silico by empirically-constrained quantitative modeling of human SAN function. CONCLUSIONS: Chronotropic incompetence and SAN dysfunction were seen in both models of HF. We identified that intrinsic abnormalities of SAN structure and function underlie the chronotropic response in HFpEF.

PD-L1 and AKT Overexpressing Adipose-Derived Mesenchymal Stem Cells Enhance Myocardial Protection by Upregulating CD25+ T Cells in Acute Myocardial Infarction Rat Model.

This study explores the synergistic impact of Programmed Death Ligand 1 (PD-L1) and Protein Kinase B (Akt) overexpression in adipose-derived mesenchymal stem cells (AdMSCs) for ameliorating cardiac dysfunction after myocardial infarction (MI). Post-MI adult Wistar rats were allocated into four groups: sham, MI, ADMSC treatment, and ADMSCs overexpressed with PD-L1 and Akt (AdMSC-PDL1-Akt) treatment. MI was induced via left anterior descending coronary artery ligation, followed by intramyocardial AdMSC injections. Over four weeks, cardiac functionality and structural integrity were assessed using pressure-volume analysis, infarct size measurement, and immunohistochemistry. AdMSC-PDL1-Akt exhibited enhanced resistance to reactive oxygen species (ROS) in vitro and ameliorated MI-induced contractile dysfunction in vivo by improving the end-systolic pressure-volume relationship and preload-recruitable stroke work, together with attenuating infarct size. Molecular analyses revealed substantial mitigation in caspase3 and nuclear factor-κB upregulation in MI hearts within the AdMSC-PDL1-Akt group. Mechanistically, AdMSC-PDL1-Akt fostered the differentiation of normal T cells into CD25+ regulatory T cells in vitro, aligning with in vivo upregulation of CD25 in AdMSC-PDL1-Akt-treated rats. Collectively, PD-L1 and Akt overexpression in AdMSCs bolsters resistance to ROS-mediated apoptosis in vitro and enhances myocardial protective efficacy against MI-induced dysfunction, potentially via T-cell modulation, underscoring a promising therapeutic strategy for myocardial ischemic injuries.

Biological Modification of Arrhythmogenic Substrates by Cell-Free Therapeutics.

Ventricular arrhythmias (VAs) represent a major cause of sudden cardiac death and afflict patients with heart failure from both ischaemic and non-ischaemic origins, and inherited cardiomyopathies. Current VA management, including anti-arrhythmic medications, autonomic modulation, implantable cardioverter-defibrillator implantation, and catheter ablation, remains suboptimal. Catheter ablation may even cause significant cardiomyocyte loss. Cell-based therapies and exosome treatment have been proposed as promising strategies to lessen cardiomyocyte death, modulate immune reaction, and reduce myocardial scarring, and, therefore, are potentially beneficial in treating VAs. In this review, we summarise the current cornerstones of VA management. We also discuss recent advances and ongoing evidence regarding cell-based and exosome therapy, with special attention to VA treatment.

Impact of Premature Ventricular Complex (PVC) Burden on the Left Ventricle in the Structurally Normal Heart: Hemodynamic Alterations of Idiopathic PVC on Echocardiography.

Background: Premature ventricular complex (PVC) without structural heart disease is mostly viewed as a benign arrhythmia. However, the high burden of PVC causes cardiomyopathy due to intraventricular dyssynchrony. The effects of ectopic contraction on left ventricular (LV) hemodynamics in the structurally normal heart are unclear. Objectives: To examine the effect of PVC burden on LV dimension, LV systolic function, and intraventricular blood flow, and to determine whether ectopic ventricular contraction affects LV hemodynamics. Methods: Patients aged ≥ 18 years with PVC ≥ 5% on Holter recording were enrolled and divided into groups G1 (5-10%), G2 (10-20%), and G3 (≥ 20%). We excluded patients with structural heart diseases, pacemakers, and LV systolic dysfunction [LV ejection fraction (LVEF) < 50%]. Clinical characteristics and routine transthoracic echocardiography parameters were compared. Results: The end-systolic LV internal dimension increased according to the PVC burden from G1 to G3 (p = 0.001). LVEF was inversely associated with PVC burden from G1 to G3 (p = 0.002). The same pattern was seen for LV outflow tract (LVOT) maximal velocity (p = 0.005) and maximal pressure gradient (PG) (p = 0.005), LVOT velocity time integral (VTI) (p = 0.03) and LV stroke volume index (LVSI) (p = 0.008). Conclusions: Systolic function and LV end-systolic dimension were inversely associated with PVC burden. Decreased LVOT flow velocity and PG were related to increased PVC burden. LVOT VTI and LVSI were smaller when the PVC burden exceeded 20%. These negative hemodynamic manifestations of idiopathic PVC were considerable even in structure normal hearts, hence the early elimination of PVC is strongly advised.

Extracellular vesicles from immortalized cardiosphere-derived cells attenuate arrhythmogenic cardiomyopathy in desmoglein-2 mutant mice.

AIMS: Arrhythmogenic cardiomyopathy (ACM) is characterized by progressive loss of cardiomyocytes, and fibrofatty tissue replacement. Extracellular vesicles (EVs) secreted by cardiosphere-derived cells, immortalized, and engineered to express high levels of ß-catenin, exert anti-inflammatory, and anti-fibrotic effects. The aim of the current study was to assess efficacy of EVs in an ACM murine model. METHODS AND RESULTS: Four-week-old homozygous knock-in mutant desmoglein-2 (Dsg2mt/mt) were randomized to receive weekly EVs or vehicle for 4 weeks. After 4 weeks, DSG2mt/mt mice receiving EVs showed improved biventricular function (left, P < 0.0001; right, P = 0.0037) and less left ventricular dilation (P < 0.0179). Electrocardiography revealed abbreviated QRS duration (P = 0.0003) and QTc interval (P = 0.0006) in EV-treated DSG2mt/mt mice. Further electrophysiology testing in the EV group showed decreased burden (P = 0.0042) and inducibility of ventricular arrhythmias (P = 0.0037). Optical mapping demonstrated accelerated repolarization (P = 0.0290) and faster conduction (P = 0.0274) in Dsg2mt/mt mice receiving EVs. DSG2mt/mt hearts exhibited reduced fibrosis, less cell death, and preserved connexin 43 expression after EV treatment. Hearts of Dsg2mt/mt mice expressed markedly increased levels of inflammatory cytokines that were, in part, attenuated by EV therapy. The pan-inflammatory transcription factor nuclear factor-κB (NF-κB), the inflammasome sensor NLRP3, and the macrophage marker CD68 were all reduced in EV-treated animals. Blocking EV hsa-miR-4488 in vitro and in vivo reactivates NF-κB and blunts the beneficial effects of EVs. CONCLUSIONS: Extracellular vesicle treatment improved cardiac function, reduced cardiac inflammation, and suppressed arrhythmogenesis in ACM. Further studies are needed prior to translating the present findings to human forms of this heterogenous disease.

Pathogenesis of arrhythmogenic cardiomyopathy: role of inflammation.

Arrhythmogenic cardiomyopathy (AC) is an inherited disease characterized by progressive breakdown of heart muscle, myocardial tissue death, and fibrofatty replacement. In most cases of AC, the primary lesion occurs in one of the genes encoding desmosomal proteins, disruption of which increases membrane fragility at the intercalated disc. Disrupted, exposed desmosomal proteins also serve as epitopes that can trigger an autoimmune reaction. Damage to cell membranes and autoimmunity provoke myocardial inflammation, a key feature in early stages of the disease. In several preclinical models, targeting inflammation has been shown to blunt disease progression, but translation to the clinic has been sparse. Here we review current understanding of inflammatory pathways and how they interact with injured tissue and the immune system in AC. We further discuss the potential role of immunomodulatory therapies in AC.

Atrial and Ventricular Response to Treatment of Premature Ventricular Complexes.

BACKGROUND: Premature ventricular complexes (PVC) may cause ventricular dyssynchrony and lead to left atrium and ventricle mechanical abnormalities. Although ventricular cardiomyopathy due to PVCs has been well studied, little is known about atrial adaptation to PVCs. OBJECTIVES: To assess atrial and ventricular responses to PVC therapy. METHODS: All patients with PVC burden > 5000 beats/day on Holter monitoring were enrolled. Baseline demographics, comorbidities, social habits, Holter parameters, and echocardiography profiles were recorded. Follow-up Holter electrocardiography (ECG) and echocardiography data were compared between PVC-treated and non-treated patients. RESULTS: Two hundred and eighty-six patients were enrolled, of whom 139 received PVC treatment. Among the treated patients, 125 who underwent follow up Holter ECG or echocardiography were included in the final analysis. The mean follow-up times of Holter ECG and echocardiography were 9.40 ± 6.70 and 9.40 ± 5.52 months, respectively. Ventricular arrhythmic burden was significantly reduced in the treatment group (16.46% vs. 13.41%, p = 0.041) but was significantly increased in the observation group (7.58% vs. 14.95%, p = 0.032). A significant increase in left atrial (LA) diameter (36.94 mm vs. 39.46 mm, p = 0.025) and reduction in left ventricular ejection fraction (LVEF) (57.26% vs. 53.8%, p = 0.040) were noted in the observation group. There were no significant differences in supraventricular arrhythmic burden in the observation group and LA diameter and LVEF in the treatment group. CONCLUSIONS: PVC therapy effectively reduced ventricular arrhythmic burden in the treatment group on follow-up. Our data suggest that PVC treatment may prevent LA dilation and LVEF decline.

Atrial Septostomy for Left Atrial Decompression During Extracorporeal Membrane Oxygenation by Inoue Balloon Catheter.

BACKGROUND: Refractory pulmonary edema is an infrequent but serious complication in patients receiving venoarterial extracorporeal membrane oxygenation (VA-ECMO) for myocardial failure. Left atrial (LA) decompression in this setting is important. Although a few methods have been reported, the experience is mostly limited to children. We aimed to evaluate the feasibility of Inoue balloon catheter in percutaneous trans-septal LA decompression in adult cardiogenic patients.Methods and Results:We retrospectively analyzed 16 procedures of trans-septal LA decompression by Inoue balloon catheter in 15 VA-ECMO patients (aged 22-65 years, 6 men) with refractory pulmonary edema from May 2012 to December 2014. Mean left ventricular ejection fraction was 15%. The cause of cardiogenic shock included 7 cases of ischemic heart disease, 1 of dilated cardiomyopathy, 5 of myocarditis, and 2 of fatal ventricular arrhythmia.The procedures were performed 4.3 days after ECMO. Inoue balloon size was 24-27 mm. LA septostomy were successfully created in 14 patients. Procedure time on average was 36.8 min (range, 15-85 min). There were no procedure-related complications.Radiography on the next day showed rapid resolution of pulmonary edema. CONCLUSIONS: Trans-septal LA decompression by Inoue balloon catheter is a feasible alternative method for adult patients with refractory pulmonary edema under ECMO.

Clinical Outcomes of Polytetrafluoroethylene-Covered Stents for Coronary Artery Perforation in Elderly Patients Undergoing Percutaneous Coronary Interventions.

BACKGROUND: Coronary artery perforation (CAP) during percutaneous coronary intervention (PCI) is associated with increased mortality. Polytetrafluoroethylene covered stents (CS) are an effective approach to treat CAP, but data regarding elderly patients requiring CS implantation for CAP are limited. The aim of this study is to report clinical data for elderly CAP patients undergoing CS implantation during PCI. METHODS: Nineteen consecutive elderly patients (≥ 65 years) undergoing CS implantation due to PCI-induced CAP in a tertiary referral center from July 2003 to April 2016 were retrospectively examined. RESULTS: There were 13 men and six women, with a mean age of 75.3 ± 5.6 years (range: 65-86 years). Perforation grade was Ellis type II in five patients (26.3%), and Ellis type III in 14 patients (73.7%). Cardiac tamponade developed in six patients (31.6%), and intra-aortic balloon pumping was needed in four patients (21.1%). The overall success rate for CS implantation rate was 94.7%. The overall in-hospital mortality rate was 15.8%; the in-hospital myocardial infarction rate was 63.2%. Among 16 survival-to-discharge cases, dual antiplatelet therapy (DAPT) was prescribed in 14 cases (87.5%) for a mean duration of 14 months. Overall, there were five angiogram- proven CS failures among 18 patients receiving successful CS implantation. The 1, 2 and 4 years of actuarial freedom from the CS failure were 78%, 65%, and 43% in the angiogram follow-up patients. CONCLUSIONS: CS implantation for CAP is feasible and effective in elderly patients, while CS failure remains a major concern that encourages regular angiographic follow-up in these case.

Increased LDL electronegativity in chronic kidney disease disrupts calcium homeostasis resulting in cardiac dysfunction.

Chronic kidney disease (CKD), an independent risk factor for cardiovascular disease, is associated with abnormal lipoprotein metabolism. We examined whether electronegative low-density lipoprotein (LDL) is mechanistically linked to cardiac dysfunction in patients with early CKD. We compared echocardiographic parameters between patients with stage 2 CKD (n = 88) and normal controls (n = 89) and found that impaired relaxation was more common in CKD patients. Reduction in estimated glomerular filtration rate was an independent predictor of left ventricular relaxation dysfunction. We then examined cardiac function in a rat model of early CKD induced by unilateral nephrectomy (UNx) by analyzing pressure-volume loop data. The time constant of isovolumic pressure decay was longer and the maximal velocity of pressure fall was slower in UNx rats than in controls. When we investigated the mechanisms underlying relaxation dysfunction, we found that LDL from CKD patients and UNx rats was more electronegative than LDL from their respective controls and that LDL from UNx rats induced intracellular calcium overload in H9c2 cardiomyocytes in vitro. Furthermore, chronic administration of electronegative LDL, which signals through lectin-like oxidized LDL receptor-1 (LOX-1), induced relaxation dysfunction in wild-type but not LOX-1(-/-) mice. In in vitro and in vivo experiments, impaired cardiac relaxation was associated with increased calcium transient resulting from nitric oxide (NO)-dependent nitrosylation of SERCA2a due to increases in inducible NO synthase expression and endothelial NO synthase uncoupling. In conclusion, LDL becomes more electronegative in early CKD. This change disrupts SERCA2a-regulated calcium homeostasis, which may be the mechanism underlying cardiorenal syndrome.

Mutation Analysis of KCNQ1, KCNH2 and SCN5A Genes in Taiwanese Long QT Syndrome Patients.

Long QT syndrome (LQTS) is a genetic cardiac disease. Gene mutation affects the structure or function of ion channels that are associated with a high risk of sudden death. The goal of this study was to determine the frequency of KCNQ1, KCNH2, and SCN5A mutations in LQTS in a Taiwanese population. Genomic DNA was extracted from peripheral blood samples obtained from 5 patients with LQTS and the family members of 3 LQTS patients. High resolution melting (HRM) analysis and direct DNA sequencing were used to characterize the KCNQ1, KCNH2, and SCN5A genetic variations. HRM analysis was successfully optimized for 14 of the 16 exons of the KCNQ1, 5 of the 15 exons of the KCNH2, and 23 of the 27 exons of the SCN5A. HRM and direct DNA sequencing was applied to the cohort of 5 cases and some of their family. The genetic testing revealed two pathogenic mutations (p.T309I in KCNQ1 and p.R744fs in KCNH2) and all of the mutational frequencies in KCNQ1 and KCNH2 were 20%. In the two patients who carry the pathogenic mutation presenting with recurrent syncope due to ventricular fibrillation, an implantable cardioverter defibrillator was implanted. We also discovered 11 polymorphisms in KCNQ1, 3 in KCNH2, and 5 in SCN5A. Two-fifths of cases (40%) presented with one of the three major LQTS-causing gene mutations.

Nationwide population-based cohort study on the association of acute coronary syndrome in patients with malignancies.

AIMS/INTRODUCTION: Patients with malignancy are suggestive of having a tendency toward an association with vascular thrombosis risk. The aim of this study was to evaluate the possible relationship between malignancy and the risk of acute coronary syndrome (ACS) in Taiwan. MATERIALS AND METHODS: We used data from the National Health Insurance (NHI) system of Taiwan to assess the issue. Cox proportional hazards regression analysis was conducted to estimate the effects of malignancy on the risk of ACS. RESULTS: ACS risk in patients with malignancies was marginally significantly greater when adjusted for age, sex (hazard ratio (HR) = 1.09, 95 % confidence interval (CI) = 0.99-1.20), and comorbidities (HR = 1.03, 95 % CI = 0.93-1.13). A subgroup analysis indicated that patients with prostate cancer and head and neck cancer (HEENT) had a significantly higher risk of ACS (HR = 1.30, 95 % CI = 1.01-1.67; HR = 3.03, 95 % CI = 1.47-6.50). CONCLUSIONS: We suggest careful surveillance of ACS symptoms and regular electrocardiography during follow-up of these patients. However, further large-scale studies for patients with prostate and HEENT cancer and cancer survivors (especially from post-hormone or radiotherapy) are needed.

Increased subsequent risk of acute coronary syndrome for patients with depressive disorder: a nationwide population-based retrospective cohort study.

AIM: The purpose of this study was to explore the possible association between subsequent acute coronary syndrome (ACS) risk and depressive disorder. METHODS: We used data from the National Health Insurance system of Taiwan to address the research topic. The exposure cohort contained 10 871 patients with new diagnoses of depressive disorders. Each patient was randomly frequency-matched for sex and age with four participants from the general population who did not have any ACS history before the index date (control group). Cox's proportion hazard regression analyses were conducted to estimate the relation between depressive disorders and subsequent ACS risk. RESULTS: Among patients with depressive disorders, the overall risk for developing subsequent ACS was significantly higher than that of the control group (adjusted hazard ratio: 1.88, 95% confidence interval: 1.63-2.17). Further analysis revealed that the higher risk was observed in patients who were male, were of older age, or whose diagnosis was combined with other comorbidities. CONCLUSIONS: The findings from this population-based retrospective cohort study suggest that depressive disorder is associated with an increased subsequent ACS risk.

Precordial ST-Segment Elevation Caused by Proximal Occlusion of a Non-Dominant Right Coronary Artery.

UNLABELLED: For patients with ST-segment elevation myocardial infarction, primary percutaneous coronary intervention to the culprit lesion via electrocardiographic guidance is essential. We herein report the rare case of a 49-year-old man who presented with ST-segment elevation in the precordial leads, while coronary angiography results indicated total occlusion of the proximal non-dominant right coronary artery. We evaluated its possible pathophysiologic mechanisms and thoroughly discussed isolated right ventricular infarction and its electrocardiography findings. KEY WORDS: Coronary angiography; Myocardial infarction; Total occlusions.

Role of low-density lipoprotein electronegativity and sexual dimorphism in contributing early ventricular tachyarrhythmias following ST-elevation myocardial infarction.

Background: Early ventricular tachycardia/fibrillation (VT/VF) in patients with ST-elevation myocardial infarction (STEMI) has higher morbidity and mortality. This study examines gender-differentiated risk factors and underlying mechanisms for early onset VT/VF in STEMI. Methods: We analyzed data from 2,964 consecutive STEMI patients between January 1, 2008 and December 31, 2021. Early VT/VF was defined as occurrence of spontaneous VT/VF of ≥30 s or requirement of immediate cardioversion/defibrillation within the first 48 h after symptoms. An ex vivo ischemic-reperfusion experiments were conducted in 8-week-old ApoE-/- mice fed a high-fat diet to explore the underlying mechanisms of early VT/VF. Results: In 255 of out 2,964 STEMI patients who experienced early VT/VF, the age was younger (58.6 ± 13.8 vs. 61.0 ± 13.0 years old, P = 0.008) with a male predominance. The plasma levels of L5, the most electronegative subclass of low-density lipoprotein, was higher in early VT/VF patients compared to those without early VT/VF (n = 21, L5: 14.1 ± 22.6% vs. n = 46, L5: 4.3 ± 9.9%, P = 0.016). In the experimental setup, all male mice (n = 4) developed VT/VF post sham operation, whereas no such incidence was observed in the female mice (n = 3). Significantly, male mice exhibited considerably slower cardiac conduction velocity as compared to their female counterparts in whole heart preparations (25.01 ± 0.93 cm/s vs.42.32 ± 5.70 cm/s, P < 0.001), despite analogous action potential durations. Furthermore, isolated ventricular myocytes from male mice showed a distinctly lower sodium current density (-29.20 ± 3.04 pA/pF, n = 6) in comparison to female mice (-114.05 ± 6.41 pA/pF, n = 6, P < 0.001). This decreased sodium current density was paralleled by a reduced membrane expression of Nav1.5 protein (0.38 ± 0.06 vs. 0.89 ± 0.09 A.U., P < 0.001) and increased cytosolic Nav1.5 levels (0.59 ± 0.06 vs. 0.29 ± 0.04 A.U., P = 0.001) in male mice. Furthermore, it was observed that the overall expressions of sorting nexin 27 (SNX27) and vacuolar protein sorting 26 (VPS26) were significantly diminished in male mice as compared to female littermates (0.91 ± 0.15 vs. 1.70 ± 0.28, P = 0.02 and 0.74 ± 0.09 vs. 1.57 ± 0.13, P < 0.01, respectively). Conclusions: Our findings reveal that male STEMI patients with early VT/VF are associated with elevated L5 levels. The gender-based discrepancy in early VT/VF predisposition might be due to compromised sodium channel trafficking, possibly linked with increased LDL electronegativity.

Sympathetic Modulation in Cardiac Arrhythmias: Where We Stand and Where We Go.

The nuance of autonomic cardiac control has been studied for more than 400 years, yet little is understood. This review aimed to provide a comprehensive overview of the current understanding, clinical implications, and ongoing studies of cardiac sympathetic modulation and its anti-ventricular arrhythmias' therapeutic potential. Molecular-level studies and clinical studies were reviewed to elucidate the gaps in knowledge and the possible future directions for these strategies to be translated into the clinical setting. Imbalanced sympathoexcitation and parasympathetic withdrawal destabilize cardiac electrophysiology and confer the development of ventricular arrhythmias. Therefore, the current strategy for rebalancing the autonomic system includes attenuating sympathoexcitation and increasing vagal tone. Multilevel targets of the cardiac neuraxis exist, and some have emerged as promising antiarrhythmic strategies. These interventions include pharmacological blockade, permanent cardiac sympathetic denervation, temporal cardiac sympathetic denervation, etc. The gold standard approach, however, has not been known. Although neuromodulatory strategies have been shown to be highly effective in several acute animal studies with very promising results, the individual and interspecies variation between human autonomic systems limits the progress in this young field. There is, however, still much room to refine the current neuromodulation therapy to meet the unmet need for life-threatening ventricular arrhythmias.

Correlations between myocardial injury current and lead performance in His bundle pacing compared with left bundle branch area pacing and right ventricular septum pacing.

BACKGROUND: Conduction system pacing by implanting the lead in the His bundle (HBP) region or in the left bundle branch area (LBBAP) has gained popularity. Myocardial injury current (IC) is useful for predicting adequate lead fixation in right ventricular septal pacing (RVSP). OBJECTIVES AND METHODS: We compared the correlations between IC and lead performance among patients receiving HBP (n = 41), LBBAP (n = 53), and historical RVSP (n = 88). LBBAP was an alternative if optimal HBP was not achieved. A positive IC (STpost-screw-in - STpre-screw-in) was defined as > 0.2 mV or a > 25% ST elevation and prolongation of the ventricular electrograms > 10 ms from baseline. RESULTS: HBP patients with a positive IC (48%, 0.84 ± 0.4 V/0.4 ms) exhibited a similar pacing threshold to their LBBAP counterparts (76%, 0.75 ± 0.3 V/0.4 ms, p = 0.329), but a higher pacing threshold than their RVSP counterparts (67%, 0.50 ± 0.1 V/0.4 ms, p < 0.001) at implantation. The R-wave (5.70 ± 3.4 mV) and impedance (660.91 ± 140.8 Ω) were both lower than those of LBBAP (10.35 ± 6.0 mV, p = 0.002; 822.36 ± 235.8 Ω, p = 0.005) and RVSP (11.24 ± 4.9 mV, p < 0.001; 754.27 ± 126.4 Ω, p = 0.006) patients respectively at implantation. The trend of electrical parameter comparisons remained unchanged during follow-up (3.56 ± 1.4 months). Notably, HBP patients without ICs had a higher pacing threshold (1.24 ± 0.6 V/0.4 ms) compared to their LBBAP (0.73 ± 0.3 V/0.4 ms, p = 0.009) and RVSP (0.53 ± 0.1 V/0.4 ms, p < 0.001) counterparts at implantation and during follow-up. CONCLUSIONS: The detection of positive changes of myocardial ICs during HBP was associated with a better capture threshold equivalent to the LBBAP counterpart both at implantation and during short-term follow-up. Further large-scale studies with longer follow-up are necessary to confirm these findings.

Association of a Common NOS1AP Variant with Attenuation of QTc Prolongation in Men with Heroin Dependence Undergoing Methadone Treatment.

Background: The effects of methadone-induced severe prolongation of the corrected QT interval (QTc) and sudden cardiac death appear unpredictable and sex-dependent. Genetic polymorphisms in the nitric oxide synthase 1 adaptor protein (NOS1AP) have been implicated in QTc prolongation in general populations. We investigated whether common NOS1AP variants interact with methadone in relation to QTc prolongation in patients with heroin dependence. Methods: We genotyped 17 NOS1AP variants spanning the entire gene in heroin-dependent patients who received a 12-lead electrocardiography (ECG) examination both at baseline and during maintenance methadone treatment in Cohort 1 and only during maintenance methadone treatment in Cohort 2. The QT interval was measured automatically by the Marquette 12SL program, and was corrected for heart rate using Bazett's formula. Results: Cohort 1 consisted of 122 patients (age: 37.65 ± 8.05 years, 84% male, methadone dosage: 42.54 ± 22.17 mg/day), and Cohort 2 comprised of 319 patients (age: 36.9 ± 7.86 years, 82% male, methadone dosage: 26.08 ± 15.84 mg/day), with complete genotyping data for analyses. Before methadone, the QTc intervals increased with increasing age (r = 0.3541, p < 0.001); the age-adjusted QTc showed dose-dependent prolongation in men (r = 0.6320, p < 0.001), but abbreviation in women (r = −0.5348, p = 0.018) in Cohort 1. The pooled genotype-specific analysis of the two cohorts revealed that the QTc interval was significantly shorter in male carriers of the rs164148 AA variant than in male carriers of the reference GG genotype (GG: n = 262, QTc = 423 ± 1.4 ms; AA: n = 10, QTc = 404.1 ± 7 ms, p = 0.009), according to univariate analysis. The QTc remained shorter in male carriers of the rs164148 AA variant compared to GG genotype (423 ± 1.4 ms vs. 405.9 ± 6.9 ms, p = 0.016) in multivariate analysis after adjusting for age and methadone dosage. A cut-off QTc interval of <410 ms identifies 100% of AA carriers compared to none of GG carriers when receiving a daily methadone dosage of 30.6 ± 19.3 mg. There was no significant gene-drug interaction in contributing to the adjusted QTc (p = 0.2164) in male carriers of the rs164148 variants. Conclusions: Carriers of a common NOS1AP rs164148 AA genotype variant were associated with a shorter QTc interval in men receiving maintenance methadone treatment. This genetic polymorphism attenuates the QTc-prolonging effect by methadone, and thus may explain at least in part the unpredictable and heterogeneous risks for severe QTc prolongation and sudden cardiac death in patients on methadone.