Antiarrhythmic Drug Therapy for Atrial Fibrillation

Meta-analysis of renin angiotensin aldosterone modulators mitigating atrial fibrillation risk in hypertensive patients

INTRODUCTION

Hypertension is associated with left ventricular hypertrophy/enlargement/fibrosis and atrial ectopic rhythm, leading to an increased risk of Atrial Fibrillation (AF). We aimed to stratify the effect of Angiotensin Converting Enzyme Inhibitors (ACEi) and Angiotensin Receptor Blockers (ARB) on the risk of AF.

METHODS

PubMed, Scopus, and Google Scholar databases were screened, and cross-citation was conducted for studies reporting AF in hypertensive patients on ACEi and ARB. Of 145 studies found till May 2023, 19 were included in this study. Binary random-effects models estimated the pooled odds ratios, I2 statistics assessed heterogeneity and sensitivity analysis was assessed using the leave-one-out method.

RESULTS

153,559 hypertensive patients met the inclusion criteria. For incidental AF, ACEi and ARB showed a significant decrease in both unadjusted (OR 0.75, 95% CI [0.66-0.85], I² = 20.79%, p=0.29) and adjusted risks (OR 0.76, 95% CI [0.62-0.93], I² = 88.41%, p<0.01). In recurrent AF, the unadjusted analysis showed no significant effect (OR 0.89, 95% CI [0.55-1.42], I² = 78.44%, p<0.01), while the adjusted analysis indicated a reduced risk (OR 0.62, 95% CI [0.50-0.76], I² = 65.71%, p<0.01). Leave-one-out sensitivity analysis confirmed these results.

CONCLUSIONS

ACEi and ARB considerably decrease the risk of incidental and recurrent AF in hypertensive patients, emphasizing the importance of treating clinical hypertension with these drugs.

Detailed analysis of electrogram peak frequency to guide ventricular tachycardia substrate mapping

AIMS

Differentiating near-field (NF) and far-field (FF) electrograms (EGMs) is crucial in identifying critical arrhythmogenic substrate during ventricular tachycardia (VT) ablation. A novel algorithm annotates NF-fractionated signals enabling EGM peak frequency (PF) determination using wavelet transformation. This study evaluated the algorithms' effectiveness in identifying critical components of the VT circuit during substrate mapping.

METHODS AND RESULTS

A multicentre, international cohort undergoing VT ablation was investigated. VT activation maps were used to demarcate the isthmus zone (IZ). Offline analysis was performed to evaluate the diagnostic performance of low-voltage area (LVA) PF substrate mapping. A total of 30 patients encompassing 198 935 EGMs were included. The IZ PF was significantly higher in sinus rhythm (SR) compared to right ventricular paced (RVp) substrate maps (234 Hz (195-294) vs. 197 Hz (166-220); P = 0.010). Compared to LVA PF, the IZ PF was significantly higher in both SR and RVp substrate maps (area under curve, AUC: 0.74 and 0.70, respectively). The LVA PF threshold of ≥200 Hz was optimal in SR maps (sensitivity 69%; specificity 64%) and RVp maps (sensitivity 60%; specificity 64%) in identifying the VT isthmus. In amiodarone-treated patients (n = 20), the SR substrate map IZ PF was significantly lower (222 Hz (186-257) vs. 303 Hz (244-375), P = 0.009) compared to amiodarone-naïve patients (n = 10). The ≥200 Hz LVA PF threshold resulted in an 80% freedom from VT with a trend towards reduced ablation lesions and radiofrequency times.

CONCLUSION

LVA PF substrate mapping identifies critical components of the VT circuit with an optimal threshold of ≥200 Hz. Isthmus PF is influenced by chronic amiodarone therapy with lower values observed during RV pacing.

Metabolic remodelling in atrial fibrillation: manifestations, mechanisms and clinical implications

Atrial fibrillation (AF) is a continually growing health-care burden that often presents together with metabolic disorders, including diabetes mellitus and obesity. Current treatments often fall short of preventing AF and its adverse outcomes. Accumulating evidence suggests that metabolic disturbances can promote the development of AF through structural and electrophysiological remodelling, but the underlying mechanisms that predispose an individual to AF are aetiology-dependent, thus emphasizing the need for tailored therapeutic strategies to treat AF that target an individual's metabolic profile. AF itself can induce changes in glucose, lipid and ketone metabolism, mitochondrial function and myofibrillar energetics (as part of a process referred to as 'metabolic remodelling'), which can all contribute to atrial dysfunction. In this Review, we discuss our current understanding of AF in the setting of metabolic disorders, as well as changes in atrial metabolism that are relevant to the development of AF. We also describe the potential of available and emerging treatment strategies to target metabolic remodelling in the setting of AF and highlight key questions and challenges that need to be addressed to improve outcomes in these patients.

Fillable Magnetic Microrobots for Drug Delivery to Cardiac Tissues In Vitro

Many cardiac diseases, such as arrhythmia or cardiogenic shock, cause irregular beating patterns that must be regulated to prevent disease progression toward heart failure. Treatments can include invasive surgery or high systemic drug dosages, which lack precision, localization, and control. Drug delivery systems (DDSs) that can deliver cargo to the cardiac injury site could address these unmet clinical challenges. Here, a microrobotic DDS that can be mobilized to specific sites via magnetic control is presented. This DDS incorporates an internal chamber that can protect drug cargo. Furthermore, the DDS contains a tunable thermosensitive sealing layer that gradually degrades upon exposure to body temperature, enabling prolonged drug release. Once loaded with the small molecule drug norepinephrine, this microrobotic DDS modulated beating frequency in induced pluripotent stem-cell derived cardiomyocytes (iPSC-CMs) in a dose-dependent manner, thus simulating drug delivery to cardiac cells in vitro. The DDS also navigates several maze-like structures seeded with cardiomyocytes to demonstrate precise locomotion under a rotating low-intensity magnetic field and on-site drug delivery. This work demonstrates the utility of a magnetically actuating DDS for precise, localized, and controlled drug delivery which is of interest for a myriad of future opportunities such as in treating cardiac diseases.

Genetics and Pharmacogenetics of Atrial Fibrillation: A Mechanistic Perspective

The heritability of atrial fibrillation (AF) is well established. Over the last decade genetic architecture of AF has been unraveled by genome-wide association studies and family-based studies. However, the translation of these genetic discoveries has lagged owing to an incomplete understanding of the pathogenic mechanisms underlying the genetic variants, challenges in classifying variants of uncertain significance (VUS), and limitations of existing disease models. We review the mechanistic insight provided by basic science studies regarding AF mechanisms, recent developments in high-throughput classification of VUS, and advances in bioengineered cardiac models for developing personalized therapy for AF.

Long QT Syndrome With Drugs Used in the Management of Arrhythmias: A Systematic Review

Long QT syndrome (LQTS) is a severe cardiac disorder characterized by an abnormally prolonged QTc interval on an electrocardiogram (ECG), which can result in life-threatening irregular heart rhythms. The use of certain medications, particularly anti-arrhythmic drugs such as quinidine, sotalol, and amiodarone, can lead to acquired LQTS by prolonging the QT interval through the inhibition of specific ion channels responsible for heart repolarization, which may present symptoms like fainting, seizures, and sudden cardiac arrest. This systematic review, conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, focused on analyzing the association between Long QT syndrome and drugs utilized for managing arrhythmias, involving a thorough examination of six selected studies from an initial pool of 68 articles. It was found that antiarrhythmic drugs such as amiodarone, sotalol, dofetilide, procainamide, quinidine, and flecainide have the potential to cause QT prolongation as a side effect, which is often influenced by factors including dosage, coexisting medical conditions, electrolyte imbalances, and other risk factors. Prolonged QT interval significantly elevates the risk of a life-threatening arrhythmia called torsade de pointes. The management of this side effect typically involves reducing the medication dosage or discontinuing it altogether and, in some cases, employing selective beta blockers. However, further research is essential to improve the understanding and implementation of strategies to prevent and manage QT prolongation caused by antiarrhythmic drugs. Additional clinical studies are warranted to enhance knowledge and provide comprehensive guidelines to healthcare practitioners regarding the appropriate use of these medications. Close monitoring of the QT interval is recommended for patients receiving anti-arrhythmic therapy, and consideration should be given to patient-specific risk factors for LQTS, including age, sex, and electrolyte imbalances.

Antiarrhythmic drug therapy and catheter ablation in patients with paroxysmal or persistent atrial fibrillation: a systematic review and meta-analysis

BACKGROUND

Catheter ablation and antiarrhythmic drug therapy are utilized for rhythm control in atrial fibrillation (AF), but their comparative effectiveness, especially with contemporary treatment modalities, remains undefined. We conducted a systematic review and meta-analysis contrasting current ablation techniques against antiarrhythmic medications for AF.

METHODS

We searched PubMed, SCOPUS, Cochrane CENTRAL, and Web of Science until November 2023 for randomized trials comparing AF catheter ablation with antiarrhythmics, against antiarrhythmic drug therapy alone, reporting outcomes for > 6 months. Four investigators extracted data and appraised risk of bias (ROB) with ROB 2 tool. Meta-analyses estimated pooled efficacy and safety outcomes using R software.

RESULTS

Twelve trials (n = 3977) met the inclusion criteria. Catheter ablation was associated with lower AF recurrence (relative risk (RR) = 0.44, 95%CI (0.33, 0.59), P ˂ 0.0001) and hospitalizations (RR = 0.44, 95%CI (0.23, 0.82), P = 0.009) than antiarrhythmic medications. Catheter ablation also improved the physical quality of life component score (assessed by a 36-item Short Form survey) by 7.61 points (95%CI -0.70-15.92, P = 0.07); but, due to high heterogeneity, it was not statistically significant. Ablation was significantly associated with higher procedural-related complications [RR = 15.70, 95%CI (4.53, 54.38), P < 0.0001] and cardiac tamponade [RR = 9.22, 95%CI (2.16, 39.40), P = 0.0027]. All-cause mortality was similar between the two groups.

CONCLUSIONS

For symptomatic AF, upfront catheter ablation reduces arrhythmia and hospitalizations better than continued medical therapy alone, albeit with moderately more adverse events. Careful patient selection and risk-benefit assessment are warranted regarding the timing of ablation.

Ablation Compared to Pharmacological Treatment for the Reduction of Atrial Fibrillation Recurrence: A Meta-Analysis

Atrial fibrillation (AF) is one of the most common heart arrhythmias, and due to its variable presentation, detecting and treating AF appropriately can reduce some of its serious complications. Among treatment options, surgical ablation and antiarrhythmic drug therapy are two of the most widely used choices. A systematic review and meta-analysis were conducted to examine the rates of AF recurrence in those treated with ablation compared to pharmacological treatment. Google Scholar and PubMed were searched for study trials published within the last decade that calculated the recurrence of AF symptoms in patient groups that received ablation or pharmacological treatment. Selected studies were analyzed in RevMan 5.4 software (The Cochrane Collaboration, London, England, UK), and each study's odds ratio and overall odds ratio were calculated using a 95% confidence interval. A total of seven studies with 2324 patients were analyzed for the meta-analysis, with 1162 patients receiving ablation and 1162 patients receiving pharmacological treatment. There was a statistically significant decrease in the recurrence of AF in the ablation group compared to the pharmacological treatment group, with a pooled odds ratio of 0.24 (CI 95% 0.14-0.39). AF treated with ablation was more effective in reducing AF recurrence than general pharmacological treatment.

Chinese guidelines for the diagnosis and management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly impacting patients' quality of life and increasing the risk of death, stroke, heart failure, and dementia. Over the past two decades, there have been significant breakthroughs in AF risk prediction and screening, stroke prevention, rhythm control, catheter ablation, and integrated management. During this period, the scale, quality, and experience of AF management in China have greatly improved, providing a solid foundation for the development of the guidelines for the diagnosis and management of AF. To further promote standardized AF management, and apply new technologies and concepts to clinical practice timely and fully, the Chinese Society of Cardiology of Chinese Medical Association and the Heart Rhythm Committee of Chinese Society of Biomedical Engineering jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. The guidelines comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2‑VASc‑60 stroke risk score based on the characteristics of the Asian AF population. The guidelines also reevaluated the clinical application of AF screening, emphasized the significance of early rhythm control, and highlighted the central role of catheter ablation in rhythm control.

Using Bayesian statistics in confirmatory clinical trials in the regulatory setting: a tutorial review

Bayesian statistics plays a pivotal role in advancing medical science by enabling healthcare companies, regulators, and stakeholders to assess the safety and efficacy of new treatments, interventions, and medical procedures. The Bayesian framework offers a unique advantage over the classical framework, especially when incorporating prior information into a new trial with quality external data, such as historical data or another source of co-data. In recent years, there has been a significant increase in regulatory submissions using Bayesian statistics due to its flexibility and ability to provide valuable insights for decision-making, addressing the modern complexity of clinical trials where frequentist trials are inadequate. For regulatory submissions, companies often need to consider the frequentist operating characteristics of the Bayesian analysis strategy, regardless of the design complexity. In particular, the focus is on the frequentist type I error rate and power for all realistic alternatives. This tutorial review aims to provide a comprehensive overview of the use of Bayesian statistics in sample size determination, control of type I error rate, multiplicity adjustments, external data borrowing, etc., in the regulatory environment of clinical trials. Fundamental concepts of Bayesian sample size determination and illustrative examples are provided to serve as a valuable resource for researchers, clinicians, and statisticians seeking to develop more complex and innovative designs.

Difference between endocardial and epicardial application of pulsed fields for targeting Epicardial Ganglia: An in-silico modelling study

BACKGROUND

Pulsed Field Ablation (PFA) has recently been proposed as a non-thermal energy to treat atrial fibrillation by selective ablation of ganglionated plexi (GP) embedded in epicardial fat. While some of PFA-technologies use an endocardial approach, others use epicardial access with promising pre-clinical results. However, as each technology uses a different and sometimes proprietary pulse application protocol, the comparation between endocardial vs. epicardial approach is almost impossible in experimental terms. For this reason, our study, based on a computational model, allows a direct comparison of electric field distribution and thermal-side effects of both approaches under equal conditions in terms of electrode design, pulse protocol and anatomical characteristics of the tissues involved.

METHODS

2D computational models with axial symmetry were built for endocardial and epicardial approaches. Atrial (1.5-2.5 mm) and fat (1-5 mm) thicknesses were varied to simulate a representative sample of what happens during PFA ablation for different applied voltage values (1000, 1500 and 2000 V) and number of pulses (30 and 50).

RESULTS

The epicardial approach was superior for capturing greater volumes of fat when the applied voltage was increased: 231 mm3/kV with the epicardial approach vs. 182 mm3/kV with the endocardial approach. In relation to collateral damage to the myocardium, the epicardial approach considerably spares the myocardium, unlike what happens with the endocardial approach. Although the epicardial approach caused much more thermal damage in the fat, there is not a significant difference between the approaches in terms of size of thermal damage in the myocardium.

CONCLUSIONS

Our results suggest that epicardial PFA ablation of GPs is more effective than an endocardial approach. The proximity and directionality of the electric field deposited using an epicardial approach are key to ensuring that higher electric field strengths and increased temperatures are obtained within the epicardial fat, thus contributing to selective ablation of the GPs with minimal myocardial damage.

Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly impacting patients' quality of life and increasing the risk of death, stroke, heart failure, and dementia. Over the past two decades, there have been significant breakthroughs in AF risk prediction and screening, stroke prevention, rhythm control, catheter ablation, and integrated management. During this period, the scale, quality, and experience of AF management in China have greatly improved, providing a solid foundation for the development of guidelines for the diagnosis and management of AF. To further promote standardized AF management, and apply new technologies and concepts to clinical practice in a timely and comprehensive manner, the Chinese Society of Cardiology of the Chinese Medical Association and the Heart Rhythm Committee of the Chinese Society of Biomedical Engineering have jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. The guidelines have comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2-VASc-60 stroke risk score based on the characteristics of AF in the Asian population. The guidelines have also reevaluated the clinical application of AF screening, emphasized the significance of early rhythm control, and highlighted the central role of catheter ablation in rhythm control.

Catheter ablation versus medical therapy in atrial fibrillation: an umbrella review of meta-analyses of randomized clinical trials

This umbrella review synthesizes data from 17 meta-analyses investigating the comparative outcomes of catheter ablation (CA) and medical treatment (MT) for atrial fibrillation (AF). Outcomes assessed were mortality, risk of hospitalization, AF recurrence, cardiovascular events, pulmonary vein stenosis, major bleeding, and changes in left ventricular ejection fraction (LVEF) and MLHFQ score. The findings indicate that CA significantly reduces overall mortality and cardiovascular hospitalization with high strength of evidence. The risk of AF recurrence was notably lower with CA, with moderate strength of evidence. Two associations reported an increased risk of pulmonary vein stenosis and major bleeding with CA, supported by high strength of evidence. Improved LVEF and a positive change in MLHFQ were also associated with CA. Among patients with AF and heart failure, CA appears superior to MT for reducing mortality, improving LVEF, and reducing cardiovascular rehospitalizations. In nonspecific populations, CA reduced mortality and improved LVEF but had higher complication rates. Our findings suggest that CA might offer significant benefits in managing AF, particularly in patients with heart failure. However, the risk of complications, including pulmonary vein stenosis and major bleeding, is notable. Further research in understudied populations may help refine these conclusions.

Vigorous physical activity and atrial fibrillation in healthy individuals: What is the correct approach?

Sport activity compared to sedentary life is associated with improved wellbeing and risk reduction in many different health conditions including atrial fibrillation (AF). Vigorous physical activity is associated with increased AF risk. We describe four individuals, who regularly perform endurance sport activity and developed AF. We discuss the changes occurring in the heart of endurance athletes and the possible etiology for AF, as well as currently available treatment options in this seemingly healthy population. Although the etiology of AF in the general population differs from the one in the usually younger endurance sport activity population, the treatment options are similar. There are several factors unique to those involved in vigorous physical activity that can influence their management. Despite a lack of evidence, endurance athletes with AF have traditionally been advised to "de-training," to reduce both the amount and intensity of exercise. Some of the current offered treatment options (beta-blockers, class III antiarrhythmic) have a varied range of adverse effect, hindering them unattractive for these individuals. Depending on risk stratification tools, anticoagulation may be indicated. Some suggest an intermittent dosing therapy, while others recommend following current guidelines. AF ablation is recommended in exercising individuals with recurrent, symptomatic AF and/or in those who do not want drug therapy, given its impact on athletic performance, AF treatment decisions should be individualized for those engaging vigorous physical activity, while considering the potential risks, the urgency of returning to training, and the will and expectations of the patient.

p38γ/δ activation alters cardiac electrical activity and predisposes to ventricular arrhythmia

Ventricular fibrillation (VF) is a leading immediate cause of sudden cardiac death. There is a strong association between aging and VF, although the mechanisms are unclear, limiting the availability of targeted therapeutic interventions. Here we found that the stress kinases p38γ and p38δ are activated in the ventricles of old mice and mice with genetic or drug-induced arrhythmogenic conditions. We discovered that, upon activation, p38γ and p38δ cooperatively increase the susceptibility to stress-induced VF. Mechanistically, our data indicate that activated p38γ and p38δ phosphorylate ryanodine receptor 2 (RyR2) disrupt Kv4.3 channel localization, promoting sarcoplasmic reticulum calcium leak, Ito current reduction and action potential duration prolongation. In turn, this led to aberrant intracellular calcium handling, premature ventricular complexes and enhanced susceptibility to VF. Blocking this pathway protected genetically modified animals from VF development and reduced the VF duration in aged animals. These results indicate that p38γ and p38δ are a potential therapeutic target for sustained VF prevention.

Reviving Hope: A Comprehensive Review of Post-resuscitation Care in Pediatric ICUs After Cardiac Arrest

This comprehensive review thoroughly examines post-resuscitation care in pediatric ICUs (PICUs) following cardiac arrest. The analysis encompasses adherence to resuscitation guidelines, advances in therapeutic interventions, and the nuanced management of neurological, cardiovascular, and respiratory considerations during the immediate post-resuscitation phase. Delving into the complexities of long-term outcomes, cognitive and developmental considerations, and rehabilitation strategies, the review emphasizes the importance of family-centered care for pediatric survivors. A call to action is presented, urging continuous education, research initiatives, and quality improvement efforts alongside strengthened multidisciplinary collaboration and advocacy for public awareness. Through implementing these principles, healthcare providers and systems can collectively contribute to ongoing advancements in pediatric post-resuscitation care, ultimately improving outcomes and fostering a culture of excellence in pediatric critical care.

Structural modeling of hERG channel-drug interactions using Rosetta

The human ether-a-go-go-related gene (hERG) not only encodes a potassium-selective voltage-gated ion channel essential for normal electrical activity in the heart but is also a major drug anti-target. Genetic hERG mutations and blockage of the channel pore by drugs can cause long QT syndrome, which predisposes individuals to potentially deadly arrhythmias. However, not all hERG-blocking drugs are proarrhythmic, and their differential affinities to discrete channel conformational states have been suggested to contribute to arrhythmogenicity. We used Rosetta electron density refinement and homology modeling to build structural models of open-state hERG channel wild-type and mutant variants (Y652A, F656A, and Y652A/F656 A) and a closed-state wild-type channel based on cryo-electron microscopy structures of hERG and EAG1 channels. These models were used as protein targets for molecular docking of charged and neutral forms of amiodarone, nifekalant, dofetilide, d/l-sotalol, flecainide, and moxifloxacin. We selected these drugs based on their different arrhythmogenic potentials and abilities to facilitate hERG current. Our docking studies and clustering provided atomistic structural insights into state-dependent drug-channel interactions that play a key role in differentiating safe and harmful hERG blockers and can explain hERG channel facilitation through drug interactions with its open-state hydrophobic pockets.

New-Onset Atrial Fibrillation in the Critically Ill COVID-19 Patients Hospitalized in the Intensive Care Unit

New-onset atrial fibrillation (NOAF) is the most frequently encountered cardiac arrhythmia observed in patients with COVID-19 infection, particularly in Intensive Care Unit (ICU) patients. The purpose of the present review is to delve into the occurrence of NOAF in COVID-19 and thoroughly review recent, pertinent data. However, the causality behind this connection has yet to be thoroughly explored. The proposed mechanisms that could contribute to the development of AF in these patients include myocardial damage resulting from direct virus-induced cardiac injury, potentially leading to perimyocarditis; a cytokine crisis and heightened inflammatory response; hypoxemia due to acute respiratory distress; disturbances in acid-base and electrolyte levels; as well as the frequent use of adrenergic drugs in critically ill patients. Additionally, secondary bacterial sepsis and septic shock have been suggested as primary causes of NOAF in ICU patients. This notion gains strength from the observation of a similar prevalence of NOAF in septic non-COVID ICU patients with ARDS. It is plausible that both myocardial involvement from SARS-CoV-2 and secondary sepsis play pivotal roles in the onset of arrhythmia in ICU patients. Nonetheless, there exists a significant variation in the prevalence of NOAF among studies focused on severe COVID-19 cases with ARDS. This discrepancy could be attributed to the inclusion of mixed populations with varying degrees of illness severity, encompassing not only patients in general wards but also those admitted to the ICU, whether intubated or not. Furthermore, the occurrence of NOAF is linked to increased morbidity and mortality. However, it remains to be determined whether NOAF independently influences outcomes in critically ill COVID-19 ICU patients or if it merely reflects the disease's severity. Lastly, the management of NOAF in these patients has not been extensively studied. Nevertheless, the current guidelines for NOAF in non-COVID ICU patients appear to be effective, while accounting for the specific drugs used in COVID-19 treatment that may prolong the QT interval (although drugs like lopinavir/ritonavir, hydrochlorothiazide, and azithromycin have been discontinued) or induce bradycardia (e.g., remdesivir).

Risk factor modification as a treatment pillar in managing atrial fibrillation

ABSTRACT

Atrial fibrillation (AF) is common, with many modifiable and nonmodifiable risk factors contributing to its increasing prevalence. Pharmacologic management and invasive procedures are the mainstays of treatment, but cardiovascular risk modification is overlooked as a key adjuvant treatment strategy. This article describes the clinical effects of implementing a risk factor modification strategy to reduce dysrhythmia load.

Comparison of the 11-Day Adhesive ECG Patch Monitor and 24-h Holter Tests to Assess the Response to Antiarrhythmic Drug Therapy in Paroxysmal Atrial Fibrillation

Accurate assessment of the response to the antiarrhythmic drug (AAD) in atrial fibrillation (AF) is crucial to achieve adequate rhythm control. We evaluated the effectiveness of extended cardiac monitoring using an adhesive ECG patch in the detection of drug-refractory paroxysmal AF. Patients diagnosed with paroxysmal AF and receiving AAD therapy were enrolled. The subjects simultaneously underwent 11-day adhesive ECG patch monitoring and a 24-h Holter test. The primary study outcome was a detection rate of drug-refractory AF or atrial tachycardia (AT) lasting ≥30 s. A total of 59 patients were enrolled and completed the study examinations. AF or AT was detected in 28 (47.5%) patients by an 11-day ECG patch monitor and in 8 (13.6%) patients by a 24-h Holter test (p < 0.001). The 11-day ECG patch monitor identified an additional 20 patients (33.8%) with drug-refractory AF not detected by the 24-h Holter, and as a result, the treatment plan was changed in 11 patients (10 catheter ablations, one medication change). In conclusion, extended cardiac rhythm monitoring using an adhesive ECG patch in patients with paroxysmal AF under AAD therapy led to over a threefold higher detection of drug-refractory AF episodes, compared to the 24-h Holter test.

Holistic Approaches to Arrhythmia Management: Combining Medication, Ablation, and Device Interventions

This narrative review investigates the severe health issue of arrhythmias, which affects millions of people worldwide. A multifaceted strategy incorporating medicine, catheter ablation, and advanced device interventions is necessary to manage these disorders effectively. Medication is the cornerstone, and as antiarrhythmic medications develop, their efficacy and side effects are reduced. Success depends on having individualized treatment strategies that consider patient profiles and arrhythmia type. Catheter ablation, a minimally invasive surgery that targets and removes faulty heart electrical circuits, has become a potent therapy when drugs are ineffective. Technological developments, including high-resolution mapping systems and customized catheters, improve precision. Pacemakers and implantable cardioverter-defibrillators (ICDs) are two examples of implantable cardiac devices essential to managing all types of arrhythmias. Pacemakers provide a regular heartbeat when the body's natural pacing mechanism fails. At the same time, ICDs, with cutting-edge algorithms, can identify and stop life-threatening arrhythmias and offer high-risk patients vital protection. As device technology advances, smaller, more durable devices become available, improving patient comfort and lowering the need for replacements. The seamless fusion of these three strategies is where holistic arrhythmia management shines. Even for difficult instances, customized combination therapy combining medicine, ablation, and device interventions offers complete solutions. Healthcare providers must collaborate for this integrated strategy to deliver personalized, efficient, and holistic care. In conclusion, the management of arrhythmias has developed into a dynamic, synergistic discipline where drugs, catheter ablation, and devices all work in concert to deliver comprehensive care. For those with arrhythmias, a patient-centered strategy that considers their particular patient features and best integrates different modalities can significantly enhance their quality of life. The effectiveness and accessibility of holistic arrhythmia management could be further improved because of ongoing developments in these fields, which is encouraging for patients and medical professionals.

In Vitro Models for Improved Therapeutic Interventions in Atrial Fibrillation

Atrial fibrillation is the most common type of cardiac arrhythmias in humans, mostly caused by hyper excitation of specific areas in the atrium resulting in dyssynchronous atrial contractions, leading to severe consequences such as heart failure and stroke. Current therapeutics aim to target this condition through both pharmacological and non-pharmacological approaches. To test and validate any of these treatments, an appropriate preclinical model must be carefully chosen to refine and optimise the therapy features to correctly reverse this condition. A broad range of preclinical models have been developed over the years, with specific features and advantages to closely mimic the pathophysiology of atrial fibrillation. In this review, currently available models are described, from traditional animal models and in vitro cell cultures to state-of-the-art organoids and organs-on-a-chip. The advantages, applications and limitations of each model are discussed, providing the information to select the appropriate model for each research application.

Atrial Fibrillation

Evidence for diagnosis and treatment of atrial fibrillation (AF) has expanded substantially since 2017, when In the Clinic last considered this subject. Direct oral anticoagulants have become the predominant therapy for thromboembolic disease, and antidotes for these drugs are now available. Device-based left atrial appendage occlusion is frequently used in patients who cannot tolerate systemic anticoagulation, and growing evidence suggests that early rhythm control improves outcomes. Catheter ablation is now frequently performed to prevent recurrent AF. Managing risk factors for AF, such as hypertension, diabetes, and obesity, remains paramount in prevention of this condition.

Risk for Bleeding-Related Hospitalizations During Use of Amiodarone With Apixaban or Rivaroxaban in Patients With Atrial Fibrillation : A Retrospective Cohort Study

BACKGROUND

Amiodarone, the most effective antiarrhythmic drug in atrial fibrillation, inhibits apixaban and rivaroxaban elimination, thus possibly increasing anticoagulant-related risk for bleeding.

OBJECTIVE

For patients receiving apixaban or rivaroxaban, to compare risk for bleeding-related hospitalizations during treatment with amiodarone versus flecainide or sotalol, antiarrhythmic drugs that do not inhibit these anticoagulants' elimination.

DESIGN

Retrospective cohort study.

SETTING

U.S. Medicare beneficiaries aged 65 years or older.

PATIENTS

Patients with atrial fibrillation began anticoagulant use between 1 January 2012 and 30 November 2018 and subsequently initiated treatment with study antiarrhythmic drugs.

MEASUREMENTS

Time to event for bleeding-related hospitalizations (primary outcome) and ischemic stroke, systemic embolism, and death with or without recent (past 30 days) evidence of bleeding (secondary outcomes), adjusted with propensity score overlap weighting.

RESULTS

There were 91 590 patients (mean age, 76.3 years; 52.5% female) initiating use of study anticoagulants and antiarrhythmic drugs, 54 977 with amiodarone and 36 613 with flecainide or sotalol. Risk for bleeding-related hospitalizations increased with amiodarone use (rate difference [RD], 17.5 events [95% CI, 12.0 to 23.0 events] per 1000 person-years; hazard ratio [HR], 1.44 [CI, 1.27 to 1.63]). Incidence of ischemic stroke or systemic embolism did not increase (RD, -2.1 events [CI, -4.7 to 0.4 events] per 1000 person-years; HR, 0.80 [CI, 0.62 to 1.03]). The risk for death with recent evidence of bleeding (RD, 9.1 events [CI, 5.8 to 12.3 events] per 1000 person-years; HR, 1.66 [CI, 1.35 to 2.03]) was greater than that for other deaths (RD, 5.6 events [CI, 0.5 to 10.6 events] per 1000 person-years; HR, 1.15 [CI, 1.00 to 1.31]) (HR comparison: P = 0.003). The increased incidence of bleeding-related hospitalizations for rivaroxaban (RD, 28.0 events [CI, 18.4 to 37.6 events] per 1000 person-years) was greater than that for apixaban (RD, 9.1 events [CI, 2.8 to 15.3 events] per 1000 person-years) (P = 0.001).

LIMITATION

Possible residual confounding.

CONCLUSION

In this retrospective cohort study, patients aged 65 years or older with atrial fibrillation treated with amiodarone during apixaban or rivaroxaban use had greater risk for bleeding-related hospitalizations than those treated with flecainide or sotalol.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute.

Heart failure with reduced ejection fraction and atrial fibrillation: a Sub-Saharan African perspective

Cardiovascular diseases are a well-established cause of death in high-income countries. In the last 20 years, Sub-Saharan Africa (SSA) has seen one of the sharpest increases in cardiovascular disease-related mortality, superseding that of infectious diseases, including HIV/AIDS, in South Africa. This increase is evidenced by a growing burden of heart failure and atrial fibrillation (AF) risk factors. AF is a common comorbidity of heart failure with reduced ejection fraction (HFrEF), which predisposes to an increased risk of stroke, rehospitalizations, and mortality compared with patients in sinus rhythm. AF had the largest relative increase in cardiovascular disease burden between 1990 and 2010 in SSA and the second highest (106.4%) increase in disability-adjusted life-years (DALY) between 1990 and 2017. Over the last decade, significant advancements in the management of both HFrEF and AF have emerged. However, managing HFrEF/AF remains a clinical challenge for physicians, compounded by the suboptimal efficacy of guideline-mandated pharmacotherapy in this group of patients. There may be an essential role for racial differences and genetic influence on therapeutic outcomes of HFrEF/AF patients, further complicating our overall understanding of the disease and its pathophysiology. In SSA, the lack of accurate and up-to-date epidemiological data on this subgroup of patients presents a challenge in our quest to prevent and reduce adverse outcomes. This narrative review provides a contemporary overview of the epidemiology of HFrEF/AF in SSA. We highlight important differences in the demographic and aetiological profile and the management of this subpopulation, emphasizing what is currently known and, more importantly, what is still unknown about HFrEF/AF in SSA.

Cardioneuroablation Using Epicardial Pulsed Field Ablation for the Treatment of Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting millions of people worldwide. The cardiac autonomic nervous system (ANS) is widely recognized as playing a key role in both the initiation and propagation of AF. This paper reviews the background and development of a unique cardioneuroablation technique for the modulation of the cardiac ANS as a potential treatment for AF. The treatment uses pulsed electric field energy to selectively electroporate ANS structures on the epicardial surface of the heart. Insights from in vitro studies and electric field models are presented as well as data from both pre-clinical and early clinical studies.

Machine learning-based analysis of risk factors for atrial fibrillation recurrence after Cox-Maze IV procedure in patients with atrial fibrillation and chronic valvular disease: A retrospective cohort study with a control group

Objectives

To evaluate the efficacy of the Cox-Maze IV procedure (CMP-IV) in combination with valve surgery in patients with both atrial fibrillation (AF) and valvular disease and use machine learning algorithms to identify potential risk factors of AF recurrence.

Methods

A total of 1,026 patients with AF and valvular disease from two hospitals were included in the study. 555 patients received the CMP-IV procedure in addition to valve surgery and left atrial appendage ligation (CMP-IV group), while 471 patients only received valve surgery and left atrial appendage ligation (Non-CMP-IV group). Kaplan-Meier analysis was used to calculate the sinus rhythm maintenance rate. 58 variables were selected as variables for each group and 10 machine learning models were developed respectively. The performance of the models was evaluated using five-fold cross-validation and metrics including F1 score, accuracy, precision, and recall. The four best-performing models for each group were selected for further analysis, including feature importance evaluation and SHAP analysis.

Results

The 5-year sinus rhythm maintenance rate in the CMP-IV group was 82.13% (95% CI: 78.51%, 85.93%), while in the Non-CMP-IV group, it was 13.40% (95% CI: 10.44%, 17.20%). The eXtreme Gradient Boosting (XGBoost), LightGBM, Category Boosting (CatBoost) and Random Fores (RF) models performed the best in the CMP-IV group, with area under the curve (AUC) values of 0.768 (95% CI: 0.742, 0.786), 0.766 (95% CI: 0.744, 0.792), 0.762 (95% CI: 0.723, 0.801), and 0.732 (95% CI: 0.701, 0.763), respectively. In the Non-CMP-IV group, the LightGBM, XGBoost, CatBoost and RF models performed the best, with AUC values of 0.738 (95% CI: 0.699, 0.777), 0.732 (95% CI: 0.694, 0.770), 0.724 (95% CI: 0.668, 0.789), and 0.716 (95% CI: 0.656, 0.774), respectively. Analysis of feature importance and SHAP revealed that duration of AF, preoperative left ventricular ejection fraction, postoperative heart rhythm, preoperative neutrophil-lymphocyte ratio, preoperative left atrial diameter and heart rate were significant factors in AF recurrence.

Conclusion

CMP-IV is effective in treating AF and multiple machine learning models were successfully developed, and several risk factors were identified for AF recurrence, which may aid clinical decision-making and optimize the individual surgical management of AF.

Novel Arylpiperazine Derivatives of Salicylamide with α1-Adrenolytic Properties Showed Antiarrhythmic and Hypotensive Properties in Rats

Cardiovascular diseases remain one of the leading causes of death worldwide. Unfortunately, the available pharmacotherapeutic options have limited effectiveness. Therefore, developing new drug candidates remains very important. We selected six novel arylpiperazine alkyl derivatives of salicylamide to investigate their cardiovascular effects. Having in mind the beneficial role of α₁-adrenergic receptors in restoring sinus rhythm and regulating blood pressure, first, using radioligand binding assays, we evaluated the affinity of the tested compounds for α-adrenergic receptors. Our experiments revealed their high to moderate affinity for α₁- but not α₂-adrenoceptors. Next, we aimed to determine the antiarrhythmic potential of novel derivatives in rat models of arrhythmia induced by adrenaline, calcium chloride, or aconitine. All compounds showed potent prophylactic antiarrhythmic activity in the adrenaline-induced arrhythmia model and no effects in calcium chloride- or aconitine-induced arrhythmias. Moreover, the tested compounds demonstrated therapeutic antiarrhythmic activity, restoring a normal sinus rhythm immediately after the administration of the arrhythmogen adrenaline. Notably, none of the tested derivatives affected the normal electrocardiogram (ECG) parameters in rodents, which excludes their proarrhythmic potential. Finally, all tested compounds decreased blood pressure in normotensive rats and reversed the pressor response to methoxamine, suggesting that their hypotensive mechanism of action is connected with the blockade of α₁-adrenoceptors. Our results confirm the antiarrhythmic and hypotensive activities of novel arylpiperazine derivatives and encourage their further investigation as model structures for potential drugs.

The Slower, the Better: Wide Complex Tachycardia Triggered by Flecainide in an Elderly Female

Class IC antiarrhythmics are generally considered a safe means of treating many common arrhythmias such as atrial fibrillation (a-fib), atrial flutter (a-flutter), and paroxysmal supraventricular tachycardia (PSVT). Essentially, flecainide works by binding and blocking sodium channels more effectively at higher heart rates. However, this class of drugs is known to exhibit use dependence which could predispose patients to the development of malignant arrhythmias during episodes of tachycardia. In this case, we present a patient who was being treated with flecainide for a-fib who ultimately developed a wide complex tachycardia after her metoprolol was held.

Artificial intelligence analysis of the impact of fibrosis in arrhythmogenesis and drug response

Background: Cardiac fibrosis has been identified as a major factor in conduction alterations leading to atrial arrhythmias and modification of drug treatment response. Objective: To perform an in silico proof-of-concept study of Artificial Intelligence (AI) ability to identify susceptibility for conduction blocks in simulations on a population of models with diffused fibrotic atrial tissue and anti-arrhythmic drugs. Methods: Activity in 2D cardiac tissue planes were simulated on a population of variable electrophysiological and anatomical profiles using the Koivumaki model for the atrial cardiomyocytes and the Maleckar model for the diffused fibroblasts (0%, 5% and 10% fibrosis area). Tissue sheets were of 2 cm side and the effect of amiodarone, dofetilide and sotalol was simulated to assess the conduction of the electrical impulse across the planes. Four different AI algorithms (Quadratic Support Vector Machine, QSVM, Cubic Support Vector Machine, CSVM, decision trees, DT, and K-Nearest Neighbors, KNN) were evaluated in predicting conduction of a stimulated electrical impulse. Results: Overall, fibrosis implementation lowered conduction velocity (CV) for the conducting profiles (0% fibrosis: 67.52 ± 7.3 cm/s; 5%: 58.81 ± 14.04 cm/s; 10%: 57.56 ± 14.78 cm/s; p < 0.001) in combination with a reduced 90% action potential duration (0% fibrosis: 187.77 ± 37.62 ms; 5%: 93.29 ± 82.69 ms; 10%: 106.37 ± 85.15 ms; p < 0.001) and peak membrane potential (0% fibrosis: 89.16 ± 16.01 mV; 5%: 70.06 ± 17.08 mV; 10%: 82.21 ± 19.90 mV; p < 0.001). When the antiarrhythmic drugs were present, a total block was observed in most of the profiles. In those profiles in which electrical conduction was preserved, a decrease in CV was observed when simulations were performed in the 0% fibrosis tissue patch (Amiodarone ΔCV: -3.59 ± 1.52 cm/s; Dofetilide ΔCV: -13.43 ± 4.07 cm/s; Sotalol ΔCV: -0.023 ± 0.24 cm/s). This effect was preserved for amiodarone in the 5% fibrosis patch (Amiodarone ΔCV: -4.96 ± 2.15 cm/s; Dofetilide ΔCV: 0.14 ± 1.87 cm/s; Sotalol ΔCV: 0.30 ± 4.69 cm/s). 10% fibrosis simulations showed that part of the profiles increased CV while others showed a decrease in this variable (Amiodarone ΔCV: 0.62 ± 9.56 cm/s; Dofetilide ΔCV: 0.05 ± 1.16 cm/s; Sotalol ΔCV: 0.22 ± 1.39 cm/s). Finally, when the AI algorithms were tested for predicting conduction on input of variables from the population of modelled, Cubic SVM showed the best performance with AUC = 0.95. Conclusion: In silico proof-of-concept study demonstrates that fibrosis can alter the expected behavior of antiarrhythmic drugs in a minority of atrial population models and AI can assist in revealing the profiles that will respond differently.

Transcriptomics-based network medicine approach identifies metformin as a repurposable drug for atrial fibrillation

Effective drugs for atrial fibrillation (AF) are lacking, resulting in significant morbidity and mortality. This study demonstrates that network proximity analysis of differentially expressed genes from atrial tissue to drug targets can help prioritize repurposed drugs for AF. Using enrichment analysis of drug-gene signatures and functional testing in human inducible pluripotent stem cell (iPSC)-derived atrial-like cardiomyocytes, we identify metformin as a top repurposed drug candidate for AF. Using the active compactor, a new design analysis of large-scale longitudinal electronic health record (EHR) data, we determine that metformin use is significantly associated with a reduced risk of AF (odds ratio = 0.48, 95%, confidence interval [CI] 0.36-0.64, p < 0.001) compared with standard treatments for diabetes. This study utilizes network medicine methodologies to identify repurposed drugs for AF treatment and identifies metformin as a candidate drug.

How synergy between mechanistic and statistical models is impacting research in atrial fibrillation

Atrial fibrillation (AF) with multiple complications, high morbidity and mortality, and low cure rates, has become a global public health problem. Although significant progress has been made in the treatment methods represented by anti-AF drugs and radiofrequency ablation, the therapeutic effect is not as good as expected. The reason is mainly because of our lack of understanding of AF mechanisms. This field has benefited from mechanistic and (or) statistical methodologies. Recent renewed interest in digital twin techniques by synergizing between mechanistic and statistical models has opened new frontiers in AF analysis. In the review, we briefly present findings that gave rise to the AF pathophysiology and current therapeutic modalities. We then summarize the achievements of digital twin technologies in three aspects: understanding AF mechanisms, screening anti-AF drugs and optimizing ablation strategies. Finally, we discuss the challenges that hinder the clinical application of the digital twin heart. With the rapid progress in data reuse and sharing, we expect their application to realize the transition from AF description to response prediction.

Understanding Antiarrhythmic Drug Efficacy for the Clinical Practitioner: There Is More than Meets the Eye

Determining if a medication is effective should be easy: Either the condition is or is not improved. However, the truth is often more complex than that, including in the antiarrhythmic drug (AAD) management of atrial fibrillation. In clinical trials, AAD efficacy is usually determined by the time to first atrial fibrillation recurrence. Another AAD efficacy endpoint, in patients with cardiac implantable electrical devices, is a reduction of atrial fibrillation burden. Other cardiovascular outcomes have included hospitalization, heart failure, and cardiovascular or total mortality. In clinical practice AADs, for atrial fibrillation, are prescribed to reduce symptoms/improve quality of life, which usually correlate with reduced atrial fibrillation frequency, duration, and beneficial hemodynamic effects in certain patient subgroups. Time to first recurrence is not a reliable predictor of clinical efficacy endpoints in practice. This article presents a review for the practitioner of AAD efficacy endpoints in clinical trials versus those in clinical practice and why such differences are present.

Electrolyte’s imbalance role in atrial fibrillation: Pharmacological management

The contribution of the perpetuation of atrial fibrillation is caused by electrical remodeling in which calcium, sodium and potassium channels could refer to changes in the ion channel protein expression, development of fibrosis, gene transcription and ion channel redistribution. Calcium and magnesium could influence the risk of atrial fibrillation which is the leading cause of cardiac death, heart failure and ischemic stroke. The elevated serum concentration of calcium had a higher range of in-patient’s mortality, increased total cost of hospitalization and increased length of hospital stay as compared to those without hypercalcemia in atrial fibrillation patients. Moreover, chloride channels could affect homeostasis, atrial myocardial metabolism which may participate in the development of atrial fibrillation. Up to a 50% risk of incidence of AF are higher in which left ventricular hypertrophy, sudden cardiovascular death and overall mortality relate to a low serum magnesium level. Additionally, magnesium prevents the occurrence of AF after cardiac surgery, whereas greater levels of serum phosphorus in the large population-based study and the related calcium–phosphorus products were linked with a greater incidence of AF. Numerous clinical studies had shown the high preoperative risk of AF that is linked with lower serum potassium levels. The conventional risk factor of increased risk of new onset of AF events could independently link with high dietary sodium intake which enhances the fibrosis and inflammation in the atrium but the mechanism remains unknown. Many drugs were used to maintain the electrolyte imbalance in AF patients.

The Increasing Role of Rhythm Control in Patients With Atrial Fibrillation: JACC State-of-the-Art Review

The considerable mortality and morbidity associated with atrial fibrillation (AF) pose a substantial burden on patients and health care services. Although the management of AF historically focused on decreasing AF recurrence, it evolved over time in favor of rate control. Recently, more emphasis has been placed on reducing adverse cardiovascular outcomes using rhythm control, generally by using safe and effective rhythm-control therapies (typically antiarrhythmic drugs and/or AF ablation). Evidence increasingly supports early rhythm control in patients with AF that has not become long-standing, but current clinical practice and guidelines do not yet fully reflect this change. Early rhythm control may effectively reduce irreversible atrial remodeling and prevent AF-related deaths, heart failure, and strokes in high-risk patients. It has the potential to halt progression and potentially save patients from years of symptomatic AF; therefore, it should be offered more widely.

Epicardial adipose tissue, obesity and the occurrence of atrial fibrillation: an overview of pathophysiology and treatment methods

INTRODUCTION

Obesity is a chronic disease, which has significant health consequences and is a staggering burden to health care systems. Obesity can have harmful effects on the cardiovascular system, including heart failure, hypertension, coronary heart disease, and atrial fibrillation (AF). One of the possible substrates might be epicardial adipose tissue (EAT), which can be the link between AF and obesity. EAT is a fat deposit located between the myocardium and the visceral pericardium. Numerous studies have demonstrated that EAT plays a pivotal role in this relationship regarding atrial fibrillation.

AREAS COVERED

This review will focus on the role of obesity and the occurrence of atrial fibrillation (AF) and examine the connection between these and epicardial adipose tissue (EAT). The first part of this review will explain the pathophysiology of EAT and its association with the occurrence of AF. Secondly, we will review bariatric and metabolic surgery and its effects on EAT and AF.

EXPERT COMMENTARY

In this review, the epidemiology, pathophysiology, and treatments methods of AF are explained. Secondly the effects on EAT were elucidated. Due to the complex pathophysiological link between EAT, AF, and obesity, it is still uncertain which treatment strategy is superior.

Emerging Antiarrhythmic Drugs for Atrial Fibrillation

Atrial fibrillation (AF), the most common cardiac arrhythmia worldwide, is driven by complex mechanisms that differ between subgroups of patients. This complexity is apparent from the different forms in which AF presents itself (post-operative, paroxysmal and persistent), each with heterogeneous patterns and variable progression. Our current understanding of the mechanisms responsible for initiation, maintenance and progression of the different forms of AF has increased significantly in recent years. Nevertheless, antiarrhythmic drugs for the management of AF have not been developed based on the underlying arrhythmia mechanisms and none of the currently used drugs were specifically developed to target AF. With the increased knowledge on the mechanisms underlying different forms of AF, new opportunities for developing more effective and safer AF therapies are emerging. In this review, we provide an overview of potential novel antiarrhythmic approaches based on the underlying mechanisms of AF, focusing both on the development of novel antiarrhythmic agents and on the possibility of repurposing already marketed drugs. In addition, we discuss the opportunity of targeting some of the key players involved in the underlying AF mechanisms, such as ryanodine receptor type-2 (RyR2) channels and atrial-selective K⁺-currents (I_K2P and I_SK) for antiarrhythmic therapy. In addition, we highlight the opportunities for targeting components of inflammatory signaling (e.g., the NLRP3-inflammasome) and upstream mechanisms targeting fibroblast function to prevent structural remodeling and progression of AF. Finally, we critically appraise emerging antiarrhythmic drug principles and future directions for antiarrhythmic drug development, as well as their potential for improving AF management.

Propafenone use in coronary artery disease patients undergoing atrial fibrillation ablation

BACKGROUND

Antiarrhythmic drugs (AADs) are frequently used after atrial fibrillation (AF) ablation. Class IC AAD use after AF ablation in patients with coronary artery disease (CAD) is uncertain. The aim was to evaluate propafenone use in CAD patients undergoing AF ablation and to compare propafenone with amiodarone regarding ventricular arrhythmia and mortality.

METHODS

In this retrospective, longitudinal cohort study, consecutive patients with mild to moderate CAD, undergoing AF ablation and receiving either propafenone (study group, n = 263) or amiodarone (control group, n = 499) in the blanking period, were included. After propensity score matching, 212 patients in each group were compared for the primary outcome defined as a composite of ventricular arrhythmic events, which included sudden cardiac death, sustained ventricular tachycardia or fibrillation, or non-sustained ventricular tachycardia (NSVT). Cardiovascular and non-cardiovascular mortality were evaluated as secondary outcomes.

RESULTS

Baseline variables of the study and control groups were well matched after propensity score matching. At 12-month follow up, 20 patients (4.7%) (11 in propafenone group and 9 in amiodarone group) experienced the primary outcome measure of NSVT (Gray test p = 0.645). No sustained ventricular tachycardia, ventricular fibrillation, sudden cardiac death, or cardiovascular mortality were observed. On multivariable competing analysis, age and diabetes but not propafenone use (hazard ratio 1.017; p = 0.804) were found to be independent and significant predictors of the primary outcome measure.

CONCLUSION

Propafenone use after AF ablation in patients with mild to moderate CAD had a safety profile similar to amiodarone and was not associated with major arrhythmic events.

Treatments of new-onset atrial fibrillation in critically ill patients: a systematic review with meta-analysis

BACKGROUND

New-onset atrial fibrillation (NOAF) is common in hospitalised patients with critical illness and associated with worse outcomes. Several interventions are available in the management of NOAF, but the overall effectiveness and safety of these interventions compared with placebo or no treatment are unknown.

METHODS

We conducted a systematic review with meta-analysis and trial sequential analysis (TSA) of randomised clinical trials (RCT) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses, the Cochrane Collaboration, and Grading of Recommendations Assessment, Development and Evaluation statements. We searched RCTs assessing any pharmacological and non-pharmacological treatment compared with placebo or no treatment in critically ill hospitalised patients with NOAF. The primary outcomes were all-cause mortality, adverse events, and health-related quality of life.

RESULTS

We included 16 trials (n = 1891) evaluating seven interventions. All trials were adjudicated 'some concerns' or 'high risk' of bias. The evidence is very uncertain for mortality (RR 0.53, 95% CI 0.03-8.30), adverse events (RR 1.28, 95% CI 0.85-1.92), and treatment efficacy i.e. rhythm control (RR 1.54, 95% CI 1.20-1.97; TSA-adjusted CI 0.56-4.53) between pharmacological treatment and placebo/no treatment (very low certainty evidence). There were no data for health-related quality of life or most of our secondary outcomes.

CONCLUSIONS

The existing data are insufficient to firmly conclude on effects of any intervention against NOAF on any outcome in hospitalised patients with critical illness. Randomised trials of the most frequently used interventions against NOAF are warranted in these patients.

Rational deuteration of dronedarone attenuates its toxicity in human hepatic HepG2 cells

Deuteration is a chemical modification strategy that has recently gained traction in drug development. The replacement of one or more hydrogen atom(s) in a drug molecule with its heavier stable isotope deuterium can enhance its metabolic stability and pharmacokinetic properties. However, it remains uninterrogated if rational deuteration at bioactivation "hot-spots" could attenuate its associated toxicological consequences. Here, our preliminary screening with benzofuran antiarrhythmic agents first revealed that dronedarone and its major metabolite N-desbutyldronedarone elicited a greater loss of viability and cytotoxicity in human hepatoma G2 (HepG2) cells as compared with amiodarone and its corresponding metabolite N-desethylamiodarone. A comparison of dronedarone and its in-house synthesized deuterated analogue (termed poyendarone) demonstrated that deuteration could attenuate its in vitro toxicity in HepG2 cells by modulating the extent of mitochondrial dysfunction, reducing the dissipation of mitochondrial membrane potential, and evoking a distinct apoptotic kinetic signature. Furthermore, although pretreatment with the CYP3A inducer rifampicin or the substitution of glucose with galactose in the growth media significantly augmented the loss of cell viability elicited by dronedarone and poyendarone, a lower loss of cell viability was consistently observed in poyendarone across all concentrations. Taken together, our preliminary investigations suggested that the rational deuteration of dronedarone at its benzofuran ring reduces aberrant cytochrome P450 3A4/5-mediated bioactivation, which attenuated its mitochondrial toxicity in human hepatic HepG2 cells.

Treatment strategies for patients with atrial fibrillation and chronic heart failure

Atrial fibrillation (AF) is associated with significant morbidity and mortality and may lead to the development of chronic heart failure (CHF). Each condition predisposes to the other, requiring a careful choice of the treatment strategy. This article is devoted to the prevalence and prognostic implications of both diseases. The article presents data from meta-analyzes related to the management of this group of patients. The aspects of rhythm control strategy in AF and concomitant CHF are described according to the recent studies and clinical guidelines. The features of anticoagulant therapy in patients with AF and CHF are outlined. Much attention is given to the importance of the safety profile of the anticoagulant therapy in terms of the bleeding risk in patients with concomitant AF and CHF.

Pharmacotherapeutic agents for the management of COVID-19 patients with preexisting cardiovascular disease

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic is the largest public health challenge of the twenty-first century. While COVID-19 primarily affects the respiratory system, manifesting as interstitial pneumonitis and severe acute respiratory distress syndrome (ARDS), it also has implications for the cardiovascular system. Moreover, those admitted to hospital with severe COVID-19 are more likely to have cardiovascular comorbidities such as hypertension and diabetes mellitus. The underlying pathophysiology of why COVID-19 onset can further decline cardiac pathologies as well as trigger acute onset of new cardiac complications is not yet well understood.

AREAS COVERED

In this review, the authors extensively review literature focused on the current understanding and approaches of managing patients who have underlying cardiovascular diseases and concomitant COVID-19 infection. Furthermore, the authors explore the possible cardiovascular implications of the suggested COVID-19 therapeutic agents that are used to treat this lethal disease.

EXPERT OPINION

Current evidence is evolving around the many trialed pharmacotherapeutic considerations for the management of coronavirus disease 2019 (COVID-19) in patients with cardiovascular disease. While we await such data, clinicians should advocate for careful consideration of all concomitant medications for those presenting with COVID-19 on a patient-by-patient basis.

Mechanisms underlying drug-mediated regulation of membrane protein function

The hydrophobic coupling between membrane proteins and their host lipid bilayer provides a mechanism by which bilayer-modifying drugs may alter protein function. Drug regulation of membrane protein function thus may be mediated by both direct interactions with the protein and drug-induced alterations of bilayer properties, in which the latter will alter the energetics of protein conformational changes. To tease apart these mechanisms, we examine how the prototypical, proton-gated bacterial potassium channel KcsA is regulated by bilayer-modifying drugs using a fluorescence-based approach to quantify changes in both KcsA function and lipid bilayer properties (using gramicidin channels as probes). All tested drugs inhibited KcsA activity, and the changes in the different gating steps varied with bilayer thickness, suggesting a coupling to the bilayer. Examining the correlations between changes in KcsA gating steps and bilayer properties reveals that drug-induced regulation of membrane protein function indeed involves bilayer-mediated mechanisms. Both direct, either specific or nonspecific, binding and bilayer-mediated mechanisms therefore are likely to be important whenever there is overlap between the concentration ranges at which a drug alters membrane protein function and bilayer properties. Because changes in bilayer properties will impact many diverse membrane proteins, they may cause indiscriminate changes in protein function.

Safety and Effectiveness of Pharmacologic Conversion of Atrial Fibrillation and Flutter: Results of Multicenter Trial. Part II: Assessment of Safety

Aim. We aimed to assess safety and effectiveness of class III antiarrhythmic drug Refralon for conversion of atrial fibrillation (AFib) and flutter (AFl) in post-registration trial and to compare data of primary center (National medical research center in cardiology) with data of other hospitals.

Material and Methods. We performed retrospective cohort study in 727 patients (451 enrolled in primary center and 276 enrolled in other hospitals) admitted between June 24, 2014 and June 24, 2019. Refralon was administered for conversion of AFib and AFl in intense care units in escalating doses (10-30 micrograms/kg) intravenously.

Results. Conversion of AFib and AFl into sinus rhythm was achieved in 53,6% after administration of 10 mcg/kg dose, in 73% after administration of 20 mcg/kg dose and in 91,6% after administration of Refralon in dose up to 30 mcg/kg. No mortality and no major adverse cardiac events registered in our study. Asystole >3.0 sec observed in 5% (35 of 727) of patients): in 5% (24 of 451) of patients enrolled in primary center and in 4% (11 of 276) of patients enrolled in other hospitals; 95% confidence interval (CI) [-0.09; 0.113]. Asystole> 5.0 s observed in 1.7% of patients who further required non-urgent implantation of a permanent pacemaker due to manifestations of sinus node dysfunction. Cardiac conduction disturbances (exclusively sinus bradycardia) were registered in 7% (53 of 727) patients: in 8% (37 of 451) of patients enrolled in primary center and in 6% (17 of 276) of patients enrolled in other hospitals; 95% CI: [-0.1; 0.15]. Only 0.14% of patients had symptomatic sinus bradycardia that resolved after atropine injection. Ventricular arrhythmias (exclusively Torsade de pointes tachycardia in excessive QT interval prolongation) were registered in 1.7% (12 of 727) patients: in 2% (9 of 451) of patients in primary center and in 1% (3 of 276) of patients of other hospitals; 95% CI: [-0.06; 0.08]. QTc interval prolongation to values >500 ms documented in 19% (138 of 727) of patients: in 21% (95 of 451) of patients in primary center and in 16% (43 of 276) of patients in other hospitals; 95% CI: [-0.13; 0.24].

Conclusion: In post-registration multicenter trial Refralon demonstrated good safety profile in conversion of AFib and AFl. Potential risk of TdP tachycardia mandates precautions with the use of the drug. In other hospitals Refralon did not demonstrate lower safety than in primary medical center.