Atrial-selective inhibition of sodium-channel current by Wenxin Keli is effective in suppressing atrial fibrillation

Natural products alleviate atrial fibrillation by modulating mitochondrial quality control

BACKGROUND

Atrial fibrillation (AF), one of the most common cardiac arrhythmias, is associated with high mortality rates and significant healthcare burdens. Mitochondrial homeostasis has recently emerged as a critical factor in AF pathogenesis but remains at the experimental stage. Current drug and surgical treatments for AF often involve side effects and require ongoing treatment plan evaluation and adjustment. In contrast, natural products (NPs), which have been utilized in China for over 2,000 years, show remarkable efficacy in treating AF and are receiving growing attention.

PURPOSE

We aimed to investigate the regulatory effects of NPs on mitochondrial quality control (MQC) and their impact on AF occurrence and progression. By constructing a novel NP-mitochondria-AF axis, we propose a framework to translate experimental findings into clinical practice and identify potential therapeutic strategies for AF.

METHODS

Databases such as PubMed, Web of Science, and China National Knowledge Infrastructure were searched (up to October 2024) using the following keywords: "atrial fibrillation," "traditional Chinese medicine," "mitochondrial biogenesis," "mitochondrial dynamics," "mitophagy," "apoptosis," "oxidative stress," "inflammation," and "Ca2+ concentration." NP targets were identified using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, while disease targets were retrieved from Online Mendelian Inheritance in Man, GeneCards, and Therapeutic Target Database. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed using the Metascape database. Protein-protein interactions were analyzed using the STRING database, and core monomers and hub genes were identified using Cytoscape 3.7.2.

RESULTS

We found a strong relationship between mitochondrial homeostasis and AF development. KEGG pathway analysis indicated that commonly used NPs regulate mitochondrial homeostasis, affecting AF progression through various hub genes, including protein kinase B-alpha (AKT1), jun proto-oncogene (JUN), and tumor necrosis factor (TNF). Molecular docking analysis revealed that NP core monomers exhibited binding affinities to hub genes below -5 kcal/mol and to transforming growth factor-β (TGF-β) below -7 kcal/mol.

CONCLUSION

NPs, including traditional Chinese medicine (TCM) compounds, TCM monomers, and traditional Chinese patent medicines, alleviate AF by modulating MQC with minimal side effects and high efficacy. These findings highlight the therapeutic potential of NPs as promising candidates for AF treatment and further underscore the importance of MQC in AF pathogenesis.

Identification of Lauric Acid as a Potent Sodium Channel NaV1.5 Blocker from Compound Chinese Medicine Wenxin Keli

Purpose

The major cardiac voltage-gated sodium channel NaV1.5 (INa) is essential for cardiac action potential initiation and subsequent propagation. Compound Chinese medicine Wenxin Keli (WXKL) has been shown to suppress arrhythmias and heart failure. However, its active components have not been fully elucidated. This study focused on identifying the active inhibitor of INa in WXKL and exploring their mode of action in electrophysiological conduction.

Methods

A chemical fraction library was constructed from an aqueous extract of WXKL and screened using an automated patch-clamping system in cells stably expressing the NaV1.5 gene SCN5A. Candidate fractions with INa-inhibition activity were analyzed by HPLC-ESI-IT-TOF-MS and GC-MS to identify the ingredients. NaV1.5 blocker molecules identified by single-cell electrocardiogram were tested in hiPSC-derived cardiomyocytes. We evaluated the SCN5A inhibitory potential of Wenxin Keli effective monomer employing molecular docking and molecular dynamics simulation approaches.

Results

A primary screen of the WXKL chemical library identified five fractions that significantly inhibited the NaV1.5 channel, with one of them rich in poly-saturated fatty acids. Molecular structural characterization revealed the presence of lauric acid, myristic acid, palmitic acid, and stearic acid in the active subfraction. Electrophysiological characterization demonstrated lauric acid (LA) as the most effective monomer for INa-inhibition with an IC50 at 27.40 ± 12.78 μM. LA shifted the steady-state inactivation of INa to more negative potentials and decreased the amplitude of extracellular field potential in hiPSC-derived cardiomyocytes. We demonstrate for the first time that naturally poly-saturated fatty acid, lauric acid, as a potential novel INa blocker. Molecular docking and molecular dynamics simulation suggested that LA binds to the NaV1.5 protein, with a significant binding affinity forming interactions with functionally essential residues and blocks the inward flow of Na+. Mechanistically, lauric acid acts on the fast inactivation of NaV1.5 alter electrophysiology conduction of hiPSC-derived cardiomyocytes and contribute to the antiarrhythmic effect of WXKL.

Conclusion

Lauric acid is a potent blocker for sodium channel NaV1.5 and alleviates arrhythmia via inhibiting INa.

Brain-to-heart cholinergic synapse-calcium signaling mediates ischemic stroke-induced atrial fibrillation

Background: Stroke-related cardiovascular diseases have attracted considerable attention, with atrial fibrillation (AF) being among the most frequent complications. Despite increasing clinical evidence, experimental models of stroke-induced AF are still lacking, hindering mechanistic discoveries and the development of adequate therapeutics targeting this stroke-heart syndrome (SHS). This study aims to create a rat model of ischemic stroke-induced AF (ISIAF) and to explore the efficacy and mechanism of Wenxin Keli (WK), an antiarrhythmic Chinese medicine. Method: The middle cerebral artery occlusion/reperfusion model was adapted to create subacute brain ischemia in rats with normal cardiac function. Invasive electrophysiologic studies and ex vivo optical mapping were performed to evaluate the altered electrophysiological parameters and Ca2+ handling properties. RNA-seq analysis, RT-PCR, and immunohistochemistry (IHC) with immunofluorescence (IF) were employed to assess the SHS model and elucidate the mechanisms of ISIAF and the effects of WK. UPLC/Q-TOF-MS, molecular docking, and whole-cell patch recordings were used to identify the active components of WK for SHS. Results: Ischemic stroke aggravated atrial electrical instability, altered action potential duration (APD), Ca2+ transient duration (CaT), conduction heterogeneity, and spatially discordant alternans in SHS rat hearts. These abnormalities were alleviated by WK. RNA-seq analysis revealed that M3-mediated cholinergic synapse signaling and L-type calcium channel (LTCCs)-mediated Ca2+ signaling play prominent roles in ISIAF development and its reversal by WK. UPLC/Q-TOF-MS analysis identified 19 WK components as the main components in plasma after WK treatment. Molecular docking screening identified Dioscin as the major active component of WK. WK and Dioscin reduced ICa-L in a concentration-dependent manner with a half-maximal inhibitory concentration of 24.254 ± 2.051 mg/mL and 8.666 ± 0.777 µmol/L, respectively. Conclusion: This study established an experimental model of ISIAF capable of characterizing clinically relevant atrial electrophysiological changes post-cerebral ischemia. Molecular mechanistic studies revealed that the cholinergic-calcium signaling pathway is central to this brain-heart syndrome. Ischemic stroke-induced atrial fibrillation is partially reversible by the Chinese medicine Wenxin Keli, which acts via regulation of the cholinergic-calcium signaling pathway, with its active component Dioscin directly binding to IKM3 and inhibiting ICa-L.

The application and mechanism of Chinese medicine in the upstream treatment of atrial fibrillation

Upstream treatment of atrial fibrillation (AF, for short) is a new approach to the prevention and treatment of AF with non-antiarrhythmic drugs, which is essentially primary and secondary prevention of AF. The former refers to the prevention of AF by controlling risk factors such as diabetes, hypertension, and heart failure before AF occurs, and the latter mainly refers to targeting ion channels, inflammation, oxidative stress, and other pathways to reduce or reverse atrial electrical and structural remodeling, reduction of AF load, and reduction of the chance of AF occurrence or progression. More and more studies have shown that many traditional Chinese medicines, active ingredients of Chinese medicines, and Chinese herbal formulas have definite effects on the upstream treatment of AF, but their mechanisms of action are different. Therefore, we summarized the relevant literature on the application and mechanisms of Chinese medicine on the upstream treatment of AF in recent years, hoping to be helpful for subsequent studies.

Advances in basic and translational research in atrial fibrillation

Atrial fibrillation (AF) is a very common cardiac arrhythmia with an estimated prevalence of 33.5 million patients globally. It is associated with an increased risk of death, stroke and peripheral embolism. Although genetic studies have identified a growing number of genes associated with AF, the definitive impact of these genetic findings is yet to be established. Several mechanisms, including electrical, structural and neural remodelling of atrial tissue, have been proposed to contribute to the development of AF. Despite over a century of exploration, the molecular and cellular mechanisms underlying AF have not been fully established. Current antiarrhythmic drugs are associated with a significant rate of adverse events and management of AF using ablation is not optimal, especially in cases of persistent AF. This review discusses recent advances in our understanding and management of AF, including new concepts of epidemiology, genetics and pathophysiological mechanisms. We review the current status of antiarrhythmic drug therapy for AF, new potential agents, as well as mechanism-based AF ablation. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.

Mechanism-based targeting of cardiac arrhythmias by phytochemicals and medicinal herbs: A comprehensive review of preclinical and clinical evidence

Cardiac arrhythmias, characterized by an irregular heartbeat, are associated with high mortality and morbidity. Because of the narrow therapeutic window of antiarrhythmic drugs (AADs), the management of arrhythmia is still challenging. Therefore, searching for new safe, and effective therapeutic options is unavoidable. In this study, the antiarrhythmic effects of medicinal plants and their active constituents were systematically reviewed to introduce some possible candidates for mechanism-based targeting of cardiac arrhythmias. PubMed, Embase, and Cochrane library were searched from inception to June 2021 to find the plant extracts, phytochemicals, and multi-component herbal preparations with antiarrhythmic activities. From 7337 identified results, 57 original studies consisting of 49 preclinical and eight clinical studies were finally included. Three plant extracts, eight multi-component herbal preparations, and 26 phytochemicals were found to have antiarrhythmic effects mostly mediated by affecting K+ channels, followed by modulating Ca2+ channels, upstream target pathways, Na v channels, gap junction channels, and autonomic receptors. The most investigated medicinal plants were Rhodiola crenulata and Vitis vinifera. Resveratrol, Oxymatrine, and Curcumin were the most studied phytochemicals found to have multiple mechanisms of antiarrhythmic action. This review emphasized the importance of research on the cardioprotective effect of medicinal plants and their bioactive compounds to guide the future development of new AADs. The most prevalent limitation of the studies was their unqualified methodology. Thus, future well-designed experimental and clinical studies are necessary to provide more reliable evidence.

Moricizine prevents atrial fibrillation by late sodium current inhibition in atrial myocytes

Background

Enhanced late sodium current (INaL) is reportedly related to an increased risk of atrial fibrillation (AF). Moricizine, as a widely used anti-arrhythmia drug for suppressing ventricular tachycardia, has also been shown to prevent paroxysmal AF. However, the mechanism of its therapeutic effect remains poorly understood.

Methods

Angiotensin II (Ang II) was induced in C57Bl/6 mice (male wild-type) for 4 weeks to increase the susceptibility of AF, and acetylcholine-calcium chloride was used to induce AF. The whole-cell patch-clamp technique was used to detect INaL from isolated atrial myocytes. The expression of proteins in atrial of mice and HL-1 cells were examined by Western-blot.

Results

The results showed that moricizine significantly inhibited Ang II-mediated atrial enlargement and reduced AF vulnerability. We found that the densities of INaL were enhanced in Ang II-treated left and right atrial cardiomyocytes. Simultaneously, the Ang II-induced increase in INaL currents density was alleviated by the administration of moricizine, and no alteration in Nav1.5 expression was observed. In normal isolated atrial myocytes, moricizine significantly reduced Sea anemone toxin II (ATX II)-enhanced INaL density with a reduction of peak sodium currents. In addition, moricizine reduced the Ang II-induced upregulation of phosphorylated calcium/calmodulin-dependent protein kinase-II (p-CaMKII) in both the left and right atria. In HL-1 cells, moricizine also reduced the upregulation of p-CaMKII with Ang II and ATX II intervention, respectively.

Conclusions

Our results indicate that Ang II enhances the INaL via activation of CaMKII. Moricizine inhibits INaL and reduces CaMKII activation, which may be one of the mechanisms of moricizine suppression of AF.

Chinese natural compound decreases pacemaking of rabbit cardiac sinoatrial cells by targeting second messenger regulation of f-channels

Tongmai Yangxin (TMYX) is a complex compound of the Traditional Chinese Medicine (TCM) used to treat several cardiac rhythm disorders; however, no information regarding its mechanism of action is available. In this study we provide a detailed characterization of the effects of TMYX on the electrical activity of pacemaker cells and unravel its mechanism of action. Single-cell electrophysiology revealed that TMYX elicits a reversible and dose-dependent (2/6 mg/ml) slowing of spontaneous action potentials rate (−20.8/–50.2%) by a selective reduction of the diastolic phase (−50.1/–76.0%). This action is mediated by a negative shift of the I_f activation curve (−6.7/–11.9 mV) and is caused by a reduction of the cyclic adenosine monophosphate (cAMP)-induced stimulation of pacemaker channels. We provide evidence that TMYX acts by directly antagonizing the cAMP-induced allosteric modulation of the pacemaker channels. Noticeably, this mechanism functionally resembles the pharmacological actions of muscarinic stimulation or β-blockers, but it does not require generalized changes in cytoplasmic cAMP levels thus ensuring a selective action on rate. In agreement with a competitive inhibition mechanism, TMYX exerts its maximal antagonistic action at submaximal cAMP concentrations and then progressively becomes less effective thus ensuring a full contribution of I_f to pacemaker rate during high metabolic demand and sympathetic stimulation.

Investigating the efficiency and tolerability of traditional Chinese formulas combined with antiarrhythmic agents for paroxysmal atrial fibrillation: A systematic review and Bayesian network meta-analysis

BACKGROUND

The combination of antiarrhythmic drugs with traditional Chinese formulas are used treatments for the management of paroxysmal atrial fibrillation (PAF). However, the most effective treatment for PAF has yet to be been determined. A Bayesian network meta-analysis study was thus performed for comparing the relative efficacy and tolerability of different treatment alternatives.

METHODS

A comprehensive literature review of randomized controlled trials (RCTs) is performed from eight database. Maintenance rate of sinus rhythm (MRSR), p-wave dispersion (Pd), left atrium diameter (LAD), left ventricular ejection fraction (LVEF), and adverse events (AEs) were used as outcomes. We also estimated treatment rank based on the surface under the cumulative ranking curve (SUCRA). This study was performed using a Bayesian network meta-analysis with a random-effects model.

FINDINGS

After screening, 59 RCTs involving 5,543 patients and 16 treatments were included. The results showed that Shensong-Yangxin capsule (SSYX) plus amiodarone (81%) was the most effective treatment for MRSR according to the value of SUCRA, followed by Wenxin-Keli granules (WXKL) plus amiodarone (73%). Meanwhile, SSYX plus amiodarone (7%) was most likely to reduce Pd, followed by SSYX plus metoprolol (23%), WXKL plus amiodarone (26%), WXKL plus bisoprolol (27%). Furthermore, SSYX plus amiodarone (4%) was more effective in improving LAD. WXKL plus amiodarone was preferred because it had the lowest toxicity. For benefit-risk ratio, amiodarone combined with WXKL or SSYX appeared to be the best option.

CONCLUSION

Antiarrhythmic agents combined with traditional Chinese formulas had higher efficacy and lower toxicity than other treatment alternatives. This study might provide reference to help find the better treatment options for PAF.

Wenxin Keli for the Treatment of Arrhythmia-Systems Pharmacology and In Vivo Pharmacological Assessment

This study employed a systems pharmacology approach to identify the active compounds and action mechanisms of Wenxin Keli for arrhythmia treatment. Sixty-eight components identified in vivo and in vitro by UPLC/Q-TOF-MS were considered the potential active components of Wenxin Keli. Network pharmacology further revealed 33 key targets and 75 KEGG pathways as possible pathways and targets involved in WK-mediated treatment, with the CaMKII/CNCA1C/Ca²⁺ pathway being the most significantly affected. This finding was validated using an AC-induced rat arrhythmias model. Pretreatment with Wenxin Keli reduced the malignant arrhythmias and shortened RR, PR, and the QT interval. Wenxin Keli exerted some antiarrhythmic effects by inhibiting p-CaMKII and intracellular Ca²⁺ transients and overexpressing CNCA1C. Thus, suppressing SR Ca²⁺ release and maintaining intracellular Ca²⁺ balance may be the primary mechanism of Wenxin Keli against arrhythmia. In view of the significance of CaMKII and NCX identified in this experiment, we suggest that CaMKII and NCX are essential targets for treating arrhythmias.

The Small Conductance Calcium-Activated Potassium Channel Inhibitors NS8593 and UCL1684 Prevent the Development of Atrial Fibrillation Through Atrial-Selective Inhibition of Sodium Channel Activity

The mechanisms underlying atrial-selective prolongation of effective refractory period (ERP) and suppression of atrial fibrillation (AF) by NS8593 and UCL1684, small conductance calcium-activated potassium (SK) channel blockers, are poorly defined. The purpose of the study was to confirm the effectiveness of these agents to suppress AF and to probe the underlying mechanisms. Transmembrane action potentials and pseudoelectrocardiograms were recorded from canine isolated coronary-perfused canine atrial and ventricular wedge preparations. Patch clamp techniques were used to record sodium channel current (INa) in atrial and ventricular myocytes and human embryonic kidney cells. In both atria and ventricles, NS8593 (3-10 µM) and UCL1684 (0.5 µM) did not significantly alter action potential duration, suggesting little to no SK channel inhibition. Both agents caused atrial-selective: (1) prolongation of ERP secondary to development of postrepolarization refractoriness, (2) reduction of Vmax, and (3) increase of diastolic threshold of excitation (all are sodium-mediated parameters). NS8593 and UCL1684 significantly reduced INa density in human embryonic kidney cells as well as in atrial but not in ventricular myocytes at physiologically relevant holding potentials. NS8593 caused a shift of steady-state inactivation to negative potentials in atrial but not ventricular cells. NS8593 and UCL1684 prevented induction of acetylcholine-mediated AF in 6/6 and 8/8 preparations, respectively. This anti-AF effect was associated with strong rate-dependent depression of excitability. The SK channel blockers, NS8593 and UCL1684, are effective in preventing the development of AF due to potent atrial-selective inhibition of INa, causing atrial-selective prolongation of ERP secondary to induction of postrepolarization refractoriness.

Comparative efficacy and safety of wenxin granule combined with antiarrhythmic drugs for atrial fibrillation: A protocol for a systematic review and network meta-analysis

BACKGROUND

The combination of Chinese patent medicine Wenxin Granules (WXG) and antiarrhythmic drugs has been widely used in the treatment of atrial fibrillation (AF), but the results are controversial. This study will conduct a network meta-analysis (NMA) based on data from randomized controlled trials to evaluate the efficacy and safety of WXG combined with ADDs (amiodarone, metoprolol, propafenone, bisoprolol, or other antiarrhythmic drugs) in the treatment of AF, which will perform comparisons or rankings of efficacy among the currently available therapeutic schemes in order to provide evidence to determine the optimal threshold and treatment regimen to AF patients.

METHODS AND ANALYSIS

A comprehensive systematic literature search will be conducted in Cochrane Library, PubMed, Web of Science, EMBASE, Chinese Biomedical Literature Database (SinoMed), Chinese National Knowledge Infrastructure (CNKI), and WanFang database for randomized controlled trials about the WXG with ADDs. The NMA will be conducted following the PRISMA-NMA guidelines. Statistical analyses will be conducted by using Stata software (version 14.0) and RevMan software (version 5.3).

RESULTS

The results of this NMA will provide a high-quality evidence for the efficacy of WXG combined with ADDs in the treatment of AF, and a ranking of the therapeutic classes will also be presented.

CONCLUSION

The protocol will provide updated evidence for the application of WXG for AF.

Wenxin Keli Regulates Mitochondrial Oxidative Stress and Homeostasis and Improves Atrial Remodeling in Diabetic Rats

Mitochondrial dysfunction and oxidative stress play an important role in the pathogenesis of both atrial fibrillation (AF) and diabetes mellitus (DM). Wenxin Keli (WXKL), an antiarrhythmic traditional Chinese medicine, has been shown to prevent cardiac arrhythmias through modulation of cardiac ion channels. This study tested the hypothesis that WXKL can improve atrial remodeling in diabetic rats by restoring mitochondrial function. Primary atrial fibroblasts of neonatal SD rats were divided into four groups: control, hydrogen peroxide (H2O2), H2O2+WXKL 1 g/L, and H2O2+WXKL 3 g/L groups. Intracellular mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and mitochondrial oxygen consumption were measured. SD male rats were randomly divided into three groups: control, DM, and DM+WXKL groups. Rats in the DM+WXKL group were treated with daily gavage of WXKL at 3 g/kg. After eight weeks, echocardiography, hemodynamic examination, histology, electrophysiology study, mitochondrial respiratory function, and western blots were assessed. H2O2 treatment led to increased ROS and decreased intracellular MMP and mitochondrial oxygen consumption in primary atrial fibroblasts. WXKL improved the above changes. DM rats showed increased atrial fibrosis, greater left atrial diameter, lower atrial conduction velocity, higher conduction heterogeneity, higher AF inducibility, and lower mitochondrial protein expression, and all these abnormal changes except for left atrial diameter were improved in the DM+WXKL group. WXKL improves atrial remodeling by regulating mitochondrial function and homeostasis and reducing mitochondrial ROS in diabetic rats.

Ion Channel Targeted Mechanisms of Anti-arrhythmic Chinese Herbal Medicine Xin Su Ning

Xin Su Ning (XSN) is a China patented and certified herbal medicine used to treat premature ventricular contractions (PVCs) since 2005. A recent completed clinical trial of 861 patients showed that XSN had similar PVC inhibition rate to the class I antiarrhythmic drug mexiletine, at 65.85% for XSN and 63.10% for mexiletine. We have previously reported that XSN prolongs action potential duration (APD) and suppresses action potential amplitude (APA) of the cardiac ventricular myocytes. In this report we aim to reveal the effect of XSN on the ionic channels that govern APD and APA, which would help to explain the cellular electrophysiological mechanism of XSN. Our main findings are: (1) On ECG recorded in isolated rat, in the presence of XSN the amplitude of R wave was significantly decreased and the amplitude of T wave was increased significantly; (2) XSN blocked hNaV1.5 channel stably transfected cell line in a dose-dependent manner with an IC₅₀ of 0.18 ± 0.02 g/L; and (3) XSN suppresses hERG channels in a dose-dependent manner with an IC₅₀ of 0.34 ± 0.01 g/L. In conclusion, the clinical antiarrhythmic efficacy of XSN is based on its class I and Class III antiarrhythmic properties by suppression hNaV1.5 channel and hERG channels, which are directly responsible for XSN’s effect on APA suppression and APD prolongation.

Efficacy of Wenxin Keli Plus Amiodarone versus Amiodarone Monotherapy in Treating Recent-Onset Atrial Fibrillation

BACKGROUND

Use of amiodarone (AMIO) in atrial fibrillation (AF) has significant side effects over prolonged periods. Wenxin Keli (WXKL), a Chinese herb extract, has been shown to be effective in atrial-selective inhibiting peak I Na and hence beneficial in treating atrial arrhythmias, including atrial fibrillation. The aim of this randomized controlled trial was to evaluate potential effects of AMIO plus WXKL on conversion rate and time in patients with recent-onset AF.

METHODS

A total of 41 patients (71 ± 12 years, 44% male) with recent-onset (<48 h) AF eligible for conversion were randomized to receive either intravenous amiodarone (loading dose 5 mg/kg in 1 hour followed by 50 mg/h; n=21) or amiodarone with same dosage plus oral WXKL 18 g thrice daily (n=20) for 24 hours.

RESULTS

Conversion rate at 24 hours was of no difference between the two groups (75.0% vs. 81.0%, P=0.72); however, conversion time was markedly shorter in the AMIO + WXKL group compared to the AMIO group (291 ± 235 minutes vs. 725 ± 475 minutes, P=0.003). There were no serious adverse events during the study.

CONCLUSION

Administration of amiodarone plus WXKL for recent-onset AF conversion was safe and effective, with faster sinus rhythm restoration compared with amiodarone alone.

Screening and Identification of Cardioprotective Compounds From Wenxin Keli by Activity Index Approach and in vivo Zebrafish Model

Wenxin Keli (WXKL) is a widely used Chinese botanical drug for the treatment of arrhythmia, which is consisted of four herbs and amber. In the present study, we analyzed the chemical composition of WXKL using liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) to tentatively identify 71 compounds. Through typical separate procession, the total extract of WXKL was divided into fractions for further bioassays. Cardiomyocytes and zebrafish larvae were applied for assessment. In vivo arrhythmia model in Cmlc2-GFP transgenic zebrafish was induced by terfenadine, which exhibited obvious reduction of heart rate and occurrence of atrioventricular block. Dynamic beating of heart was recorded by fluorescent microscope and sensitive camera to automatically recognize the rhythm of heartbeat in zebrafish larvae. By integrating the chemical information of WXKL and corresponding bioactivities of these fractions, activity index (AI) of each identified compound was calculated to screen potential active compounds. The results showed that dozens of compounds including ginsenoside Rg₁, ginsenoside Re, notoginsenoside R₁, lobetyolin, and lobetyolinin were contributed to cardioprotective effects of WXKL. The anti-arrhythmic activities of five compounds were further validated in larvae model and mature zebrafish by measuring electrocardiogram (ECG). Our findings provide a successful example for rapid discovery of bioactive compounds from traditional Chinese medicine (TCM) by activity index based approach coupled with in vivo zebrafish model.

Therapeutic Effects of Wenxin Keli in Cardiovascular Diseases: An Experimental and Mechanism Overview

Cardiovascular diseases (CVDs) are the major public health problem and a leading cause of morbidity and mortality on a global basis. Wenxin Keli (WXKL), a formally classical Chinese patent medicine with obvious efficacy and favorable safety, plays a great role in the management of patients with CVDs. Accumulating evidence from various animal and cell studies has showed that WXKL could protect myocardium and anti-arrhythmia against CVDs. WXKL exhibited its cardioprotective roles by inhibiting inflammatory reaction, decreasing oxidative stress, regulating vasomotor disorders, lowering cell apoptosis, and protection against endothelial injure, myocardial ischemia, cardiac fibrosis, and cardiac hypertrophy. Besides, WXKL could effectively shorten the QRS and Q-T intervals, decrease the incidence of atrial/ventricular fibrillation and the number of ventricular tachycardia episodes, improve the severity of arrhythmias by regulating various ion channels with different potencies, mainly comprising peak sodium current (INa), late sodium current (INaL), transient outward potassium current (Ito), L-type calcium current (ICaL), and pacemaker current (If).

Mechanisms and Drug Development in Atrial Fibrillation

Atrial fibrillation is a highly prevalent cardiac arrhythmia and the most important cause of embolic stroke. Although genetic studies have identified an increasing assembly of AF-related genes, the impact of these genetic discoveries is yet to be realized. In addition, despite more than a century of research and speculation, the molecular and cellular mechanisms underlying AF have not been established, and therapy for AF, particularly persistent AF, remains suboptimal. Current antiarrhythmic drugs are associated with a significant rate of adverse events, particularly proarrhythmia, which may explain why many highly symptomatic AF patients are not receiving any rhythm control therapy. This review focuses on recent advances in AF research, including its epidemiology, genetics, and pathophysiological mechanisms. We then discuss the status of antiarrhythmic drug therapy for AF today, reviewing molecular mechanisms, and the possible clinical use of some of the new atrial-selective antifibrillatory agents, as well as drugs that target atrial remodeling, inflammation and fibrosis, which are being tested as upstream therapies to prevent AF perpetuation. Altogether, the objective is to highlight the magnitude and endemic dimension of AF, which requires a significant effort to develop new and effective antiarrhythmic drugs, but also improve AF prevention and treatment of risk factors that are associated with AF complications.

Recent advances in the treatment of Brugada syndrome

INTRODUCTION

Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome characterized by ST-segment elevation in right precordial ECG leads and associated with sudden cardiac death in young adults. The ECG manifestations of BrS are often concealed but can be unmasked by sodium channel blockers and fever. Areas covered: Implantation of a cardioverter defibrillator (ICD) is first-line therapy for BrS patients presenting with prior cardiac arrest or documented VT. A pharmacological approach to therapy is recommended in cases of electrical storm, as an adjunct to ICD and as preventative therapy. The goal of pharmacological therapy is to produce an inward shift to counter the genetically-induced outward shift of ion channel current flowing during the early phases of the ventricular epicardial action potential. This is accomplished by augmentation of I_Ca using □□adrenergic agents or phosphodiesterase III inhibitors or via inhibition of I_to. Radiofrequency ablation of the right ventricular outward flow tract epicardium is effective in suppressing arrhythmogenesis in BrS patients experiencing frequent appropriate ICD-shocks. Expert commentary: Understanding of the pathophysiology and approach to therapy of BrS has advanced considerably in recent years, but there remains an urgent need for development of cardio-selective and ion-channel-specific I_to blockers for treatment of BrS.

Wenxin Keli for atrial fibrillation: Protocol for a systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) is a most common cardiac arrhythmia in clinical practice. In China, Wenxin Keli (WXKL) therapy is a common treatment for AF, but its effects and safety remain uncertain. This protocol is to provide the methods used to assess the effectiveness and safety of WXKL for the treatment of patients with AF.

METHODS

We will search comprehensively the 4 English databases EMBASE, the Cochrane Central Register of Controlled Trials (Cochrane Library), PubMed, and Medline and 3 Chinese databases China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), and Chinese Science and Technology Periodical database (VIP) on computer on March 2018 for the randomized controlled trials (RCTs) regarding WXKL for AF. The therapeutic effects according to the sinus rhythm and p-wave dispersion (Pwd) will be accepted as the primary outcomes. We will use RevMan V.5.3 software as well to compute the data synthesis carefully when a meta-analysis is allowed.

RESULTS

This study will provide a high-quality synthesis of current evidence of WXKL for AF.

CONCLUSION

The conclusion of our systematic review will provide evidence to judge whether WXKL is an effective intervention for patient with AF.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD 42018082045.

Pharmacological Therapy in Brugada Syndrome

Brugada syndrome (BrS) is a cardiac disease caused by an inherited ion channelopathy associated with a propensity to develop ventricular fibrillation. Implantable cardioverter defibrillator implantation is recommended in BrS, based on the clinical presentation in the presence of diagnostic ECG criteria. Implantable cardioverter defibrillator implantation is not always indicated or sufficient in BrS, and is associated with a high device complication rate. Pharmacological therapy aimed at rebalancing the membrane action potential can prevent arrhythmogenesis in BrS. Quinidine, a class 1A antiarrhythmic drug with significant Ito blocking properties, is the most extensively used drug for the prevention of arrhythmias in BrS. The present review provides contemporary data gathered on all drugs effective in the therapy of BrS, and on ineffective or contraindicated antiarrhythmic drugs.

Effect of Wenxin Granules on Gap Junction and MiR-1 in Rats with Myocardial Infarction

Myocardial infarction (MI) patients are at high risk of potential lethal arrhythmia. Gap junction and microRNA-1 (miR-1) are both arrhythmia generating conditions. The present study investigated whether Wenxin Granules (Wenxin-Keli, WXKL) could prevent potential lethal arrhythmia by improving gap junctions and miR-1 following MI. Male Sprague-Dawley rats were divided randomly into control, model, metoprolol, low dose WXKL, and high dose WXKL groups. The MI rat model was created by coronary artery ligation. Treatments were administrated intragastrically to the rats for 4 weeks. Conventional transmission electron microscopy was performed to observe the ultrastructure of gap junctions. Quantitative real-time PCR and western blotting were used to detect the expression of miR-1, protein kinase C (PKC), and related proteins. Additionally, a programmatic electrophysiological stimulation test was performed to detect the ventricular fibrillation threshold (VFT). WXKL protected the ultrastructure of the gap junctions and their constituent Cx43 by regulating miR-1 and PKC mediated signal transduction and increased the VFT significantly in the rat MI model. The results suggested that WXKL is an effective alternative medicine to prevent potentially lethal arrhythmia following MI.

Comparative metabonomics of Wenxin Keli and Verapamil reveals differential roles of gluconeogenesis and fatty acid β-oxidation in myocardial injury protection

Metabonomics/metabolomics is a rapid technology for comprehensive profiling of small molecule metabolites in cells, tissues, or whole organisms, the application of which has led to understanding pathophysiologic mechanisms of cardiometabolic diseases, defining predictive biomarkers for those diseases, and also assessing the efficacious effects of incident drugs. In this study, proton nuclear magnetic resonance (NMR)-based metabonomics was employed to identify the metabolic changes in rat plasma caused by myocardial ischemia-reperfusion injury (MIRI), and to compare the metabolic regulatory differences between traditional Chinese medicine Wenxin Keli (WXKL) and Western medicine verapamil. The results revealed that energy-substrate metabolism were significantly disturbed by ischemia-reperfusion (I/R) in myocardium and bulk of the key metabolites could be further modulated by verapamil and/or WXKL. Lipid metabolism and amino acid transamination occurred mainly following the treatment of verapamil, whereas glucose oxidation and BCAA degradation were prominently ameliorated by WXKL to content the energy demands of heart. Moreover, both WXKL and verapamil improved the secretions of taurine and ketone bodies to overcome the oxidative stress and the shortage of energy sources induced by ischemia-reperfusion.

Wenxin Keli for Ventricular premature complexes with Heart failure: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

OBJECTIVE

To evaluate the efficacy and safety of Wenxin Keli (WXKL) alone or combined with Western medicine in treating ventricular premature complexes (VPCs) with heart failure (HF).

METHODS

We searched five databases to identify relevant randomized controlled trials (RCTs) published before May 2016. Two review authors independently searched and screened the literature, extracted the data as well as assessed the methodological quality of the included studies by using criteria from the Cochrane Handbook, and analyzed via using Review Manager 5.3 software.

RESULTS

Eight studies of WXKL were included. The results of the Meta-analysis showed that WXKL was more significant on the frequency of VPCs (MD=-427.08, 95% CI: -526.73∼-327.43, P<0.01), left ventricular ejection fraction (LVEF) (MD=-4.12, 95% CI: 2.97∼5.27, P<0.01), the total effect of VPCs (RR=0.48, 95% CI: 0.34∼0.69, P<0.01) and 6-min walking test (MD=28.05, 95% CI: 19.56∼36.54, P<0.01). The treatment group presented a significant reduction at left ventricular end-diastolic diameter (LVED) (MD=-3.94, 95% CI: -6.57∼-1.31, P<0.01) when treatment time was 12 weeks, however, there was no statistical difference at 8 weeks. In addition, the included trials generally showed low methodological quality.

CONCLUSIONS

Wenxin Keli may be effective and safe for treating VPCs and HF. However, further RCTs of larger scale, multi-center/country, longer follow-up periods, and higher quality are still required to verify the efficacy of Wenxin Keli in ventricular premature beat with heart failure.

Comparative Effectiveness of Acupuncture and Antiarrhythmic Drugs for the Prevention of Cardiac Arrhythmias: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Introduction and Objectives: This study was designed to systematically evaluate the effectiveness of acupuncture treatment for arrhythmia compared to existing drug therapy. Methods: Randomized controlled trials (RCTs) were identified through searches of the MEDLINE, CNKI, Embase, and Cochrane databases (1970 through 2016) and hand searches of cross-references from original articles and reviews. Clinical trials that randomized arrhythmia patients to acupuncture therapy vs. conventional drugs, sham acupuncture, or bed rest were included for analysis. Results: A total of 13 trials with 797 patients met the criteria for analysis. The results of the meta-analysis showed no statistically significant difference between acupuncture and conventional treatment for paroxysmal supraventricular tachycardia (PSVT) (n = 203; RR, 1.18; 95% CI 0.78-1.79; I² = 80%; P = 0.44). However, in the ventricular premature beat (VPB) group, it showed a significant benefit of acupuncture plus oral administration of anti-arrhythmic drug (AAD) on response rates compared with the oral administration of AAD (n = 286; RR, 1.15; 95% CI 1.05-1.27; I² = 0%; P = 0.002). Finally, when compared with the sinus tachycardia (ST) cases without any treatment, acupuncture has benefited these patients (n = 120; MD, 18.80, 95% CI 12.68-24.92; I² = 81%; P < 0.00001). Conclusions: In summary, our meta-analysis demonstrates that clinical efficacy of acupuncture is not less than AAD for PSVT. Furthermore, in sub-group analysis, acupuncture with or without AAD, shows a clear benefit in treating VPB and ST. However, more definitive RCTs are warranted to guide clinical practice.

The Role of Biologically Active Ingredients from Natural Drug Treatments for Arrhythmias in Different Mechanisms

Arrhythmia is a disease that is caused by abnormal electrical activity in the heart rate or rhythm. It is the major cause of cardiovascular morbidity and mortality. Although several antiarrhythmic drugs have been used in clinic for decades, their application is often limited by their adverse effects. As a result, natural drugs, which have fewer side effects, are now being used to treat arrhythmias. We searched for all articles on the role of biologically active ingredients from natural drug treatments for arrhythmias in different mechanisms in PubMed. This study reviews 19 natural drug therapies, with 18 active ingredient therapies, such as alkaloids, flavonoids, saponins, quinones, and terpenes, and two kinds of traditional Chinese medicine compound (Wenxin-Keli and Shensongyangxin), all of which have been studied and reported as having antiarrhythmic effects. The primary focus is the proposed antiarrhythmic mechanism of each natural drug agent. Conclusion. We stress persistent vigilance on the part of the provider in discussing the use of natural drug agents to provide a solid theoretical foundation for further research on antiarrhythmia drugs.

Application of Traditional Chinese Medicine in Treatment of Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia, which is related to many cardiac and cerebral vascular diseases, especially stroke. It can therefore increase cardiovascular mortality and all-cause death. The current treatments of AF remain to be western drugs and radiofrequency ablation which are limited by the tolerance of patients, adverse side effects, and high recurrence rate, especially for the elderly. On the contrary, traditional Chinese medicine (TCM) with long history of use involves various treatment methods, including Chinese herbal medicines (CHMs) or bioactive ingredients, Chinese patent medicines, acupuncture, Qigong, and Tai Chi Chuan. With more and more researches reported, the active roles of TCM in AF management have been discovered. Then it is likely that TCM would be effective preventive means and valuable additional remedy for AF. The potential mechanisms further found by numerous experimental studies showed the distinct characteristics of TCM. Some CHMs or bioactive ingredients are atrial-selective, while others are multichannel and multifunctional. Therefore, in this review we summarized the treatment strategies reported in TCM, with the purpose of providing novel ideas and directions for AF management.

An integrated anti-arrhythmic target network of a Chinese medicine compound, Wenxin Keli, revealed by combined machine learning and molecular pathway analysis

Deciphering the compound Wenxin Keli's anti-arrhythmic pharmacological mechanism by integrating network pharmacology and experimental verification methods.

The Effect of Wenxin Keli on the mRNA Expression Profile of Rabbits with Myocardial Infarction

Aims. The molecular mechanisms of Chinese traditional medicine Wenxin Keli (WXKL) were unknown. This study was aimed at exploring the effects of WXKL on the gene expression profile and pathological alteration of rabbits with myocardial infarction. Methods. Twenty male adult rabbits were randomly divided into 4 groups: sham, model, WXKL, and captopril groups. Model, WXKL, and captopril groups underwent the ligation of the left anterior descending coronary artery while sham group went through an identical procedure without ligation. WXKL (817 mg/kg/d), captopril (8 mg/kg/d), and distilled water (to model and sham groups) were administered orally to each group. After 4 weeks, the rabbits were examined with echocardiography and the hearts were taken for expression chip and pathological staining (H&E, Masson, and Tunel) studies. Results. The data revealed that WXKL downregulated genes associated with inflammation (CX3CR1, MRC1, and FPR1), apoptosis (CTSC and TTC5), and neurohumoral system (ACE and EDN1) and upregulated angiogenesis promoting genes such as RSPO3. Moreover, the results also showed that WXKL improved cardiac function and prevented histopathological injury and apoptosis. Conclusion. The present study demonstrated that WXKL might play an important role in inhibiting inflammation, renin-angiotensin system, and apoptosis. It might be a promising Chinese medicine in the treatment of patients with myocardial infarction.

Efficacy and safety of Chinese herbal medicine Wenxin Keli for ventricular premature be ats: A systematic review

BACKGROUND

To evaluate the efficacy and safety of the Chinese herbal extract Wenxin Keli, alone or in combination with Western medicine, for ventricular premature beats.

METHODS

This systematic review was registered at PROSPERO (registration number CRD42013003200). A systematic literature search of 8 core electronic databases and 3 clinical trial registries in Chinese and English, yielded 10 trials whose randomness verified by contacting the authors. The included trials were assessed by the Cochrane risk of bias tool.

RESULTS

Wenxin Keli might be more efficacious than placebo (Change of VPBs numbers, RR, 1.61, 95%CI, 1.48-1.76, P<0.00001, I²=0%;VPBs- related symptom, RR, 2.10, 95%CI, 1.91-2.30, P<0.00001, I²=0%), and the dual therapy of Wenxin Keli plus amiodarone might also be more effective than the monotherapy of amiodarone (Change of VPBs numbers, RR, 1.23, 95%CI, 1.10-1.39, P=0.0005, I²=0%; VPBs- related symptom, RR, 1.51., 95%CI, 1.30-1.76, P<0.00001, I²=0%), whereas Wenxin Keli might be comparable to metoprolol, propafenone or mexiletine (Change of VPBs numbers: metoprolol, RR, 1.01, 95%CI, 0.91-1.11, P=0.88, I²=0%; propafenone, RR, 1.05, 95%CI, 0.93-1.19, P=0.44, I²=0%; mexiletine, RR, 1.06, 95%CI, 0.96-1.17, P=0.28. VPBs- related symptom: metoprolol, RR, 0.95, 95%CI, 0.87-1.04, P=0.27, I²=0%, propafenone. RR, 1.10, 95%CI, 0.93-1.30, P=0.29, I²=29%, mexiletine,RR, 0.94, 95%CI, 0.78-1.12, P=0.47). Participants with ventricular premature beats' numbers<360 beats/h or with coronary heart disease benefited the most of the Wenxin Keli therapy (Change of VPBs numbers:RR, 1.10, 95%CI, 1.02-1.20, P=0.02, I²=44%; RR, 1.71, 95%CI, 1.18-2.49, P=0.005, I²=54%, respectively). The safety analysis revealed that Wenxin Keli did not statistically significant differed from the Western medicine in respect of the incidence of total adverse drug reactions (RR, 0.59, 95%CI, 0.35-1.01, P=0.05, I²=0%), but Wenxin Keli might be associated with a reduced risk of proarrhythmic reactions (P=0.007). The quality of the methodology of included trials was generally low. Several limitations existed that affected the validity of the findings, including the small sample size, insufficient randomization methods, poorly defined eligibility criteria, short duration of follow-up, absence of hard endpoints, and high risk of publication bias(P=0.013).

CONCLUSIONS

Wenxin Keli might be a promising alternative and complementary medicine for ventricular premature beats.

Atrial-selective block of sodium channels by acehytisine in rabbit myocardium

Acehytisine, a multi-ion channel blocker, can markedly inhibit I_Na, I_Ca, I_Kur, I_f at various concentrations and effectively terminate and prevent atrial fibrillation (AF) in patients and animal models, but the molecular mechanism underlying its blockage remains elusive. In this study, we investigated the effects of acehytisine on action potentials and sodium channels of atrial and ventricular myocytes isolated from rabbit, using whole-cell recording system. We found that acehytisine exerted stronger blocking effects on sodium channels in atria than in ventricles, especially at depolarization (IC₅₀: 48.48 ± 7.75 μmol/L in atria vs. 560.17 ± 63.98 μmol/L in ventricles). It also significantly shifted steady state inactivation curves toward negative potentials in atrial myocytes, without affecting the recovery kinetics from inactivation of sodium channels in the same cells. In addition, acehytisine inhibited I_Na in a use-dependent manner and regulated slow inactivation kinetics by different gating configurations. These findings indicate that acehytisine selectively blocks atrial sodium channels and possesses affinity to sodium channel in certain states, which provides additional evidence for the anti-AF of acehytisine.

The Efficacy and Safety of Wenxin Keli in Patients with Frequent Premature Ventricular Contractions: A Randomized, Double-blind, Placebo-controlled, Parallel-group, Multicenter Trial

BACKGROUND

Premature ventricular contractions (PVCs) are common in the general population, and frequent PVCs may result in the poor quality of life or even the damage of cardiac function. We examined the efficacy and safety of a traditional Chinese medicine Wenxin Keli for the treatment of frequent PVCs among a relatively large Chinese cohort.

METHODS

We performed a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial. A total of 1200 eligible participants were randomly assigned in a ratio of 1:1 to receive Wenxin Keli or the placebo for 4 weeks. The primary and secondary endpoint was the change of PVC numbers and PVC-related symptoms after a 4-week treatment compared with baseline, respectively. In addition, vital signs, laboratory values, and electrocardiographic parameters were assessed in a safety analysis.

RESULTS

At the initial evaluation, no significant differences in the baseline characteristics were observed between the Wenxin Keli group and the placebo group. A smaller number of PVCs was observed after the 4-week treatment than at baseline, in both the Wenxin Keli group (5686 ± 5940 vs. 15,138 ± 7597 beats/d, P < 0.001) and the placebo group (10,592 ± 8009 vs. 14,529 ± 5929 beats/d, P < 0.001); moreover, the Wenxin Keli group demonstrated a significantli greater reduction in the frequency of PVCs than the placebo group (P < 0.001). In a full analysis set, patients in the Wenxin Keli group exhibited significantly higher total effective responses in the reduction of PVCs compared to those in the placebo group (83.8% vs. 43.5%,P < 0.001). The per-protocol analysis yielded similar results (83.0% vs. 39.3%,P < 0.001). Treatment with Wenxin Keli also demonstrated superior performance compared to the placebo with respect to PVC-related symptoms. No severe adverse effects attributable to Wenxin Keli were reported.

CONCLUSIONS

Wenxin Keli treatment effectively reduced the overall number of PVCs and alleviated PVC-related symptoms in patients without structural heart diseases and had no severe side effects.

Mechanisms underlying atrial-selective block of sodium channels by Wenxin Keli: Experimental and theoretical analysis

INTRODUCTION

Atrial-selective inhibition of cardiac sodium channel current (INa) and INa-dependent parameters has been shown to contribute to the safe and effective management of atrial fibrillation. The present study was designed to examine the basis for the atrial-selective actions of Wenxin Keli.

METHODS

Whole cell INa was recorded at room temperature in canine atrial and ventricular myocytes. Trains of 40 pulses were elicited over a range of pulse durations and interpulse intervals to determine tonic and use-dependent block. A Markovian model for INa that incorporates interaction of Wenxin Keli with different states of the channel was developed to examine the basis for atrial selectivity of the drug.

RESULTS

Our data indicate that Wenxin Keli does not bind significantly to either closed or open states of the sodium channel, but binds very rapidly to the inactivated state of the channel and dissociates rapidly from the closed state. Action potentials recorded from atrial and ventricular preparations in the presence of 5g/L Wenxin Keli were introduced into the computer model in current clamp mode to simulate the effects on maximum upstroke velocity (Vmax). The model predicted much greater inhibition of Vmax in atrial vs. ventricular cells at rapid stimulation rates.

CONCLUSION

Our findings suggest that atrial selectivity of Wenxin Keli to block INa is due to more negative steady-state inactivation, less negative resting membrane potential, and shorter diastolic intervals in atrial vs. ventricular cells at rapid activation rates. These actions of Wenxin Keli account for its relatively safe and effective suppression of atrial fibrillation.

Brugada Syndrome: Clinical, Genetic, Molecular, Cellular, and Ionic Aspects

Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome first described as a new clinical entity in 1992. Electrocardiographically characterized by distinct coved type ST segment elevation in the right-precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young adults, and less frequently in infants and children. The electrocardiographic manifestations of BrS are often concealed and may be unmasked or aggravated by sodium channel blockers, a febrile state, vagotonic agents, as well as by tricyclic and tetracyclic antidepressants. An implantable cardioverter defibrillator is the most widely accepted approach to therapy. Pharmacologic therapy is designed to produce an inward shift in the balance of currents active during the early phases of the right ventricular action potential (AP) and can be used to abort electrical storms or as an adjunct or alternative to device therapy when use of an implantable cardioverter defibrillator is not possible. Isoproterenol, cilostazol, and milrinone boost calcium channel current and drugs like quinidine, bepridil, and the Chinese herb extract Wenxin Keli inhibit the transient outward current, acting to diminish the AP notch and thus to suppress the substrate and trigger for ventricular tachycardia or fibrillation. Radiofrequency ablation of the right ventricular outflow tract epicardium of patients with BrS has recently been shown to reduce arrhythmia vulnerability and the electrocardiographic manifestation of the disease, presumably by destroying the cells with more prominent AP notch. This review provides an overview of the clinical, genetic, molecular, and cellular aspects of BrS as well as the approach to therapy.

Effect of berberine on acetylcholine-induced atrial fibrillation in rabbit

The purpose of this study was to test the efficacy of Berberine (Ber) on atrial fibrillation (AF) induced by acetylcholine (ACh) and explore its underlying mechanisms of action. In vivo electrophysiology experiments were performed in adult anesthetized rabbits. Single atrial myocytes were isolated from rabbit hearts and action potentials recorded using patch clamp techniques. AF was induced by rapid atrial burst pacing during intravenous (IV) ACh infusion alone or with IV Ber. Compared to the Baseline, IV Ber (2 mg/kg) prolonged the RR interval and effective refractory period (195 ± 10 vs. 215 ± 11 msec; 80 ± 4 vs. 85 ± 5 msec, respectively; both P<0.05). The induced rate of sustained 1 min AF was lower during ACh infusion with Ber than during ACh infusion alone (4/10 vs. 30/35, P<0.01). The termination rate of ACh-induced AF was higher with IV Ber (1 mg/kg) than with IV saline (sustained 1 min AF: 6/8 vs. 6/20, sustained 10 min AF: 8/10 vs. 1/6, both P<0.05). ACh perfusion significantly shortened the action potential duration (APD) of isolated atrial myocytes (APD50: 152 ± 13 vs. 81 ± 10 msec; APD90: 256 ± 19 vs. 132 ± 13 msec, both P<0.01). Application of Ber reversed the APD shortening induced by ACh (APD50: 81 ± 10 vs. 134 ± 15 msec; APD90: 132 ± 13 vs: 213 ± 17 msec, both P<0.01). We conclude that Ber suppresses ACh-induced AF in the rabbit by increasing atrial effective refractory period and prolonging the APD of atrial myocytes.

J-wave syndromes: Brugada and early repolarization syndromes

A prominent J wave is encountered in a number of life-threatening cardiac arrhythmia syndromes, including the Brugada syndrome and early repolarization syndromes. Brugada syndrome and early repolarization syndromes differ with respect to the magnitude and lead location of abnormal J waves and are thought to represent a continuous spectrum of phenotypic expression termed J-wave syndromes. Despite two decades of intensive research, risk stratification and the approach to therapy of these 2 inherited cardiac arrhythmia syndromes are still undergoing rapid evolution. Our objective in this review is to provide an integrated synopsis of the clinical characteristics, risk stratifiers, and molecular, ionic, cellular, and genetic mechanisms underlying these 2 fascinating syndromes that have captured the interest and attention of the cardiology community in recent years.

Evaluation of Melissa officinalis (Lemon Balm) Effects on Heart Electrical System

Background:

Melissa officinalis, an herbal drug, is well known and frequently applied in traditional and modern medicine. Yet, there is inadequate information regarding its effects on electrical properties of the heart. The present study attempted to elucidate the effects of Melissa officinalis aqueous extract on electrocardiogram (ECG) in rat.

Objectives:

ECG is an easy, fast and valuable tool to evaluate the safety of used materials and drugs on heart electrical and conductivity properties. Many drugs with no cardiovascular indication or any overt cardiovascular effects of therapeutic dosing become cardiotoxic when overdosed (16). On the other hand, there are numerous substances and drugs that can cause ECG changes, even in patients without a history of cardiac disease. Therefore, this study was conducted to elucidate safety and outcome of one-week administration of M. officinalis aqueous extract on blood pressure and ECG parameters of rats.

Materials and Methods:

Four animal groups received tap water (control group), aqueous extracts of Melissa officinalis 50 (M50), 100 (M100) and 200 (M200) mg/kg/day, respectively and orally for a week. ECG and blood pressure were recorded on the eighth day of experiment.

Results:

Consumption of Melissa officinalis extract associated with prolonged QRS interval (P < 0.05 for M50 and M100 groups and P < 0.01 for M200 group versus the control group, respectively), prolonged QTc and JT intervals (P < 0.01 for different M groups versus the control group) and prolonged TpTe interval (P < 0.001 when M groups compared with the control group) of ECG. However, different doses of the extract had no significant effect on RR interval, PR interval, amplitudes of ECG waves, heart rate and blood pressure.

Conclusions:

For the first time, this study revealed that consumption of Melissa officinalis extract is associated with significant ECG alterations in rat. Future studies are necessary to determine potential clinical outcomes.

Wenxin Keli versus Sotalol for Paroxysmal Atrial Fibrillation Caused by Hyperthyroidism: A Prospective, Open Label, and Randomized Study

We aimed to compare effectiveness of Wenxin Keli (WK) and sotalol in assisting sinus rhythm (SR) restoration from paroxysmal atrial fibrillation (PAF) caused by hyperthyroidism, as well as in maintaining SR. We randomly prescribed WK (18 g tid) or sotalol (80 mg bid) to 91 or 89 patients. Since it was not ethical not to give patients antiarrhythmia drugs, no control group was set. Antithyroid drugs were given to 90 patients (45 in WK group, 45 in sotalol group); ¹³¹I was given to 90 patients (46 in WK group, 44 in sotalol group). Three months later, SR was obtained in 83/91 or 80/89 cases from WK or sotalol groups (P = 0.762). By another analysis, SR was obtained in 86/90 or 77/90 cases from ¹³¹I or ATD groups (P = 0.022). Then, we randomly assigned the successfully SR-reverted patients into three groups: WK, sotalol, and control (no antiarrhythmia drug was given) groups. After twelve-month follow-up, PAF recurrence happened in 1/54, 2/54, and 9/55 cases, respectively. Log-Rank test showed significant higher PAF recurrent rate in control patients than either treatment (P = 0.06). We demonstrated the same efficacies of WK and sotalol to assist SR reversion from hyperthyroidism-caused PAF. We also showed that either drug could maintain SR in such patients.

Novel Therapeutic Strategies for the Management of Ventricular Arrhythmias Associated with the Brugada Syndrome

INTRODUCTION

Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome characterized by prominent J waves appearing as distinct coved type ST segment elevation in the right precordial leads of the ECG. It is associated with a high risk for sudden cardiac death.

AREAS COVERED

We discuss 1) ECG manifestations of BrS which can be unmasked or aggravated by sodium channel blockers, febrile states, vagotonic agents, as well as tricyclic and tetracyclic antidepressants; 2) Genetic basis of BrS; 3) Ionic and cellular mechanisms underlying BrS; 4) Therapy involving devices including an implantable cardioverter defibrillator (ICD); 5) Therapy involving radiofrequency ablation; and 6) Therapy involving pharmacological therapy which is aimed at producing an inward shift in the balance of the currents active during phase 1 of the right ventricular action potential either by boosting calcium channel current (isoproterenol, cilostazol and milrinone) or by inhibition of transient outward current Ito (quinidine, bepridil and the Chinese herb extract Wenxin Keli).

EXPERT OPINION

This review provides an overview of the clinical and molecular aspects of BrS with a focus on approaches to therapy. Available data suggest that agents capable of inhibiting the transient outward current Ito can exert an ameliorative effect regardless of the underlying cause.

Alternative medicine in atrial fibrillation treatment-Yoga, acupuncture, biofeedback and more

The last decade has seen a significant improvement in the management of atrial fibrillation (AF) with the development of newer medications and improvement in catheter ablation techniques. Recurrence of AF remains a significant problem in these patients and medications offer limited supportive role. Complementary and alternative treatment strategies therefore remain a viable option for these AF patients. Several studies have shown improvement in AF symptoms with yoga therapy, acupuncture and biofeedback. There are also several herbal medicine and supplements such as omega-3 fatty acids, antioxidant vitamins, barberry, motherwort, cinchona, Shensongyangxin, hawthorn, Kella and Wenxin Keli that have been evaluated as potential therapeutic options in AF. These studies are however limited by small sample sizes with mixed results. Besides the pharmacological action, metabolism, interactions with other medications and the adverse effects of the herbal medications and supplements remain poorly understood. In spite of the above limitations, complementary therapies remain a promising option in the management of AF and further studies are necessary to validate their safety and efficacy.

Atria are More Sensitive Than Ventricles to GS-458967-Induced Inhibition of Late Sodium Current

INTRODUCTION

The differential response of atrial and ventricular cells to late sodium channel current (late INa) inhibition has not been thoroughly investigated. The aim of the present study was to compare the atrioventricular differences in electrophysiological actions of GS-458967, a potent late INa blocker.

METHODS AND MATERIALS

Canine coronary-perfused atrial and ventricular preparations and isolated ventricular myocytes were used. Transmembrane action potentials were recorded using standard microelectrode recording techniques.

RESULTS

In coronary-perfused preparations paced at a cycle length (CL) of 500 ms, GS-458967 (100-300 nmol/L) significantly abbreviated action potential duration at 50% to 90% (APD50-90) in atria but not in the ventricles. GS-458967 (≥100 nmol/L) prolonged the effective refractory period (ERP) in atria due to the development of postrepolarization refractoriness (PRR) but did not alter ERP in the ventricles. The maximum rate of rise in the action potential upstroke (Vmax) was significantly reduced at concentrations ≥100 nmol/L in atria but not in the ventricles (CL = 300 ms). At slower pacing rates (CL = 2000 ms) and higher concentrations, GS-458967 (100-1000 nmol/L) still failed to abbreviate ventricular APD. However, when APD was prolonged by the rapidly activating delayed rectifier potassium channel blocker E-4031 (1 µmol/L), addition of 1 μmol/L GS-458967 abbreviated APD in the ventricles at slow rates. In contrast, GS-458967 (300 nmol/L) consistently abbreviated APD in untreated isolated ventricular myocytes.

CONCLUSION

In canine coronary-perfused preparations, GS-458967 abbreviates APD, induces PRR, and reduces Vmax in atria but has no significant effect on these parameters in the ventricles, indicating an atrial-selective effect of GS-458967 on both peak and late INa-mediated parameters. In multicellular preparations, GS-458967 abbreviated ventricular APD only under long QT conditions, suggesting a pathology-specific action of GS-458967 in canine ventricular myocardium.

The effects of wenxin keli on left ventricular ejection fraction and brain natriuretic Peptide in patients with heart failure: a meta-analysis of randomized controlled trials

Objective. To evaluate the beneficial and adverse effects of Wenxin Keli (WXKL), either alone or in combination with Western medicine, on the left ventricular ejection fraction (LVEF) and plasma brain natriuretic peptide (BNP) in the treatment of heart failure (HF). Methods. Seven major electronic databases were searched to retrieve potential randomized controlled trials (RCTs) designed to evaluate the clinical effectiveness of WXKL, either alone or in combination with Western medicine, for HF, with the LVEF or BNP after eight weeks of treatment as main outcome measures. The methodological quality of the included studies was assessed using criteria from the Cochrane Handbook for Systematic Review of Interventions, Version 5.1.0, and analyzed using RevMan 5.1.0 software. Results. Eleven RCTs of WXKL were included. The methodological quality of the trials was generally evaluated as low. The risk of bias was high. The results of the meta-analysis showed that WXKL, either alone or in combination with Western medicine, was more effective in LVEF and BNP, compared with no medicine or Western medicine alone, in patients with HF or HF complicated by other diseases. Five of the trials reported adverse events, while the others did not mention them, indicating that the safety of WXKL remains uncertain. Conclusions. WXKL, either alone or in combination with Western medicine, appears to be more effective in improving the LVEF and BNP in patients with HF and HF complications.