Rhythm control in atrial fibrillation

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.

Atrial fibrillation considerations in the fourth trimester (postpartum period)

Postpartum atrial fibrillation is an uncommon but increasingly prevalent tachyarrhythmia that merits special management considerations with regards to the safety and efficacy of anticoagulation, rate and rhythm control as well as drug exposure to infants throughout breastfeeding. In this state-of-the-art review, we examine the demographics of postpartum atrial fibrillation with its associated risk factors, describe the safety of commonly used atrial fibrillation therapies, and discuss important considerations for women considering subsequent pregnancies.

Cryoablation Utilizing the KODEX-EPD Mapping System Versus Conventional Cryoballoon Ablation in the Management of Patients With Atrial Fibrillation: A Literature Review and Meta-Analysis

Atrial fibrillation (AF) is the most commonly encountered cardiac arrhythmia globally. AF is associated with different consequences, such as peripheral vascular embolism, stroke, dementia, heart failure, and death. Catheter ablation (CA) has become a reliable therapeutic option for symptomatic AF. Utilizing mapping systems in conducting cryoablation is supposed to improve pulmonary vein isolation (PVI) durability and overall treatment success rate. We performed a review of relevant articles. We formulated a search strategy as follows: (atrial fibrillation AND ("cryoballoon ablation" OR cryoablation) AND (KODEX-EPD AND KODEX OR mapping). Data were collected from Web of Science, PubMed, Cochrane Library, and SCOPUS databases. We assessed the efficacy, procedural characteristics, and safety of cryoablation using the KODEX-EPD mapping system versus conventional cryoablation. We demonstrated the superiority of cryoablation guided by the KODEX-EPD system as it was associated with a significantly lower recurrence rate after the procedure (RR = 0.61, P = 0.03). Furthermore, it allowed a significant reduction in the volume of contrast medium used during the procedure (MD = -20.46, P = 0.04) when compared to the conventional cryoablation. We found no significant difference between both procedures in terms of successful cryoballoon-based PVI (P = 1.00), procedural duration (P = 0.95), procedural complications (P = 0.607), fluoroscopic time (P = 0.36), and fluoroscopic dose (P = 0.16). The use of the novel KODEX-EPD mapping system in the cryoablation procedure was associated with a significant reduction of the volume of contrast medium use and the recurrence rate compared with the conventional cryoablation while preserving similar efficacy, safety profile, and procedure time.

Advancements in gene therapy approaches for atrial fibrillation: Targeted delivery, mechanistic insights and future prospects

Atrial fibrillation (AF) remains a complex and challenging arrhythmia to treat, necessitating innovative therapeutic strategies. This review explores the evolving landscape of gene therapy for AF, focusing on targeted delivery methods, mechanistic insights, and future prospects. Direct myocardial injection, reversible electroporation, and gene painting techniques are discussed as effective means of delivering therapeutic genes, emphasizing their potential to modulate both structural and electrical aspects of the AF substrate. The importance of identifying precise targets for gene therapy, particularly in the context of AF-associated genetic, structural, and electrical abnormalities, is highlighted. Current studies employing animal models, such as mice and large animals, provide valuable insights into the efficacy and limitations of gene therapy approaches. The significance of imaging methods for detecting atrial fibrosis and guiding targeted gene delivery is underscored. Activation mapping techniques offer a nuanced understanding of AF-specific mechanisms, enabling tailored gene therapy interventions. Future prospects include the integration of advanced imaging, activation mapping, and percutaneous catheter-based techniques to refine transendocardial gene delivery, with potential applications in both ventricular and atrial contexts. As gene therapy for AF progresses, bridging the translational gap between preclinical models and clinical applications is imperative for the successful implementation of these promising approaches.

Elective cardioversion at a district general hospital: a retrospective evaluation of outcomes

Direct current cardioversion is a procedure for treating abnormal heart rhythms, and cardioversion is often performed electively to restore sinus rhythm in patients with persistent atrial fibrillation or atrial flutter. A retrospective evaluation of elective cardioversion data at a local general hospital was undertaken to evaluate the success and outcomes of cardioversion. This evaluation also considered the outcomes for two subsets of patients with heart failure and obesity, as it has previously been concluded that cardioversion is unsuccessful in these patients. Immediate success rates of cardioversion were high in general and remained high initially in heart failure and obese patients, but there was a drop-off in longer term success in all groups.

Atrial fibrillation: better symptom control with rate and rhythm management

Atrial fibrillation (AF) is often associated with limiting symptoms, and with significant impairment in quality of life. As such, treatment strategies aimed at symptom control form an important pillar of AF management. Such treatments include a wide variety of drugs and interventions, including, increasingly, catheter ablation. These strategies can be utilised either singly or in combination, to improve and restore quality of life for patients, and this review covers the current evidence base underpinning their use. In this Review, we discuss the pros and cons of rate vs. rhythm control, while offering practical tips to non-specialists on how to utilise various treatments and counsel patients about all relevant treatment options. These include antiarrhythmic and rate control medications, as well as interventions such as cardioversion, catheter ablation, and pace-and-ablate.

[Perioperative atrial fibrillation : Diagnosis with underestimated relevance]

Atrial fibrillation (AF) is the most common cardiac arrhythmia in adults, both in general and perioperatively and is associated with significant morbidity and mortality. The age of the patients is a major risk factor. The prevalence of AF in noncardiac surgery (NCS) varies widely from 0.4% to 30% and for cardiac surgery, especially major combined procedures, up to approximately 50%. Ectopic excitation centers and reentry mechanisms at the atrial level are favored as the main process of uncoordinated electrical atrial activity. The loss of atrial contraction can lead to a reduction in cardiac output of up to 20-25%. The increased risk of thromboembolism due to AF extends beyond the perioperative period. Medication-based prevention strategies have not yet gained widespread acceptance. Treatment strategies include frequency and rhythm control as well as the avoidance of thromboembolisms through anticoagulation.

Computational Studies Show How the H463R Mutation Turns hKv1.5 into an Inactivation State

The KCNA5 gene provides the code for the α-subunit of the potassium channel Kv1.5. The genetic variant H463R in the Kv1.5 channel has been reported to cause a functional loss in atrial fibrillation (AF) patients. Understanding the mutations at a molecular level is key to developing improved therapeutics concerning cardiac hKv1.5 and hKv1.4 channels. Molecular dynamics and umbrella sampling free energy simulations are an effective tool to understand the mutation's effect on ion conduction, which we have employed and found that the hKv1.5[H463R] mutation imposes an energy barrier on the ion conduction pathway compared to the wild-type channel's ion free energy and pore structure. These results imply that the arginine mutation associated with the AF disease in particular modulates the inactivation process of hKv1.5. Kv1.4, encoded by the KCNA4 gene, is also present in the heart. Therefore, we considered simulation studies of the equivalent H507R mutation in the hKv1.4 channel and found that the mutation slightly reduces the ion conduction barrier in the ion conduction pathway, making it insignificant.

Efficacy and safety of atrial fibrillation ablation in heart failure patients with left ventricular ejection fraction less than 50

INTRODUCTION

The efficacy of catheter ablation in patients with low cardiac function has been previously reported; however, only a few studies have included mid-range ejection fraction (mrEF). This study aimed to evaluate the efficacy and safety of atrial fibrillation (AF) ablation in patients with left ventricular ejection fraction (LVEF) < 50%.

METHODS

This study retrospectively analyzed 79 patients (reduced ejection fraction [rEF]/mrEF, 38/41; paroxysmal/persistent, 37/42; heart failure hospitalizations within one year before ablation, 36 [45.6%]) who underwent the first ablation procedure at our hospital from April 2017 to December 2021. Radiofrequency ablation and cryoablation were performed for 69 and 10 patients, respectively.

RESULTS

Complications included pacemaker implantation for postoperative sick sinus syndrome in one patient and inguinal hematoma in one patient. Regarding efficacy, there were significant postoperative improvements in echocardiographic data, blood test values, and diuretic use. After a mean follow-up of 60 months, 86.1% patients had no AF recurrence. There were 9 heart failure hospitalizations (11.4%) and 5 all-cause deaths (6.3%); no significant differences were found between the rEF and mrEF groups. No significant predictors of AF recurrence were found in preoperative patient characteristics.

CONCLUSION

AF ablation in patients with LVEF <50% significantly improved cardiac and renal functions with few complications, resulting in a high non-recurrence rate and reduced heart failure.

Visit-to-Visit Heart Rate Variability in the Prediction of Clinical Outcomes of Patients with Atrial Fibrillation

BACKGROUND

 Visit-to-visit heart rate variability (VVV-HR) has been associated with adverse cardiovascular outcomes. We aimed to determine the predictive value of VVV-HR for adverse clinical outcomes in patients with nonvalvular atrial fibrillation (AF).

METHODS

 We used data from a prospective multicenter AF registry of 27 hospitals in Thailand during 2014 to 2017. After the baseline visit, patients were followed up every 6 months until 3 years. VVV-HR was calculated from the standard deviation of heart rate data from baseline visit and every follow-up visit. VVV-HR was categorized into four groups according to the quartiles. Clinical outcomes were all-cause death, ischemic stroke/systemic embolism (SE), and heart failure. Cox proportional hazard models were used for multivariable analysis.

RESULTS

 There were a total of 3,174 patients (mean age: 67.7 years; 41.8% female). The incidence rates of all-cause death, ischemic stroke/SE, and heart failure were 3.10 (2.74-3.49), 1.42 (1.18-1.69), and 2.09 (1.80-2.42) per 100 person-years respectively. The average heart rate was 77.8 ± 11.0 bpm and the average of standard deviation of heart rate was 11.0 ± 5.9 bpm. VVV-HR Q4 was an independent predictor of all-cause death, ischemic stroke/SE, and heart failure with adjusted hazard ratios of 1.45 (95% confidence interval: 1.07-1.98), 2.02 (1.24-3.29), and 2.63 (1.75-3.96), respectively. VVV-HR still remained a significant predictor of clinical outcomes when analyzed based on coefficient of variation and variability independent of mean.

CONCLUSION

 VVV-HR is an independent predictor for adverse clinical outcomes in patients with AF. A J-curve appearance was demonstrated for the effect of VVV-HR on all-cause death.

Network meta-analysis and systematic review comparing efficacy and safety between very high power short duration, high power short duration, and conventional radiofrequency ablation of atrial fibrillation

BACKGROUND

High-power short-duration (HPSD) atrial fibrillation (AF) ablation with a power of 40-50 W was proved to be safe and effective. Very high-power short-duration (vHPSD) AF ablation is a novel method using >50 W to obtain more durable AF ablation. This study aimed to evaluate the efficacy and safety of vHPSD ablation compared with HPSD ablation and conventional power ablation.

METHODS

A literature search for studies that reported AF ablation outcomes, including short-term freedom from atrial arrhythmia, first-pass isolation (FPI) rate, procedure time, and major complications, was conducted utilizing MEDLINE, EMBASE, and Cochrane databases. All relevant studies were included in this analysis. A random-effects model of network meta-analysis and surface under cumulative ranking curve (SUCRA) were used to rank the treatment for all outcomes.

RESULTS

A total of 29 studies with 9721 patients were included in the analysis. According to the SUCRA analysis, HPSD ablation had the highest probability of maintaining sinus rhythm. Point estimation showed an odds ratio of 1.5 (95% confidence interval [CI]: 1.2-1.9) between HPSD ablation and conventional power ablation and an odds ratio of 1.3 (95% CI: 0.78-2.2) between vHPSD ablation and conventional power ablation. While the odds ratio of FPI between HPSD ablation and conventional power ablation was 3.6 (95% CI: 1.5-8.9), the odds ratio between vHPSD ablation and conventional power ablation was 2.2 (95% CI: 0.61-8.6). The procedure times of vHPSD and HPSD ablations were comparable and, therefore, shorter than that of conventional power ablation. Major complications were low in all techniques.

CONCLUSION

vHPSD ablation did not yield higher efficacy than HPSD ablation and conventional power ablation. With the safety concern, vHPSD ablation outcomes were comparable with those of other techniques.

Impact of Achieving Blood Pressure Targets and High Time in Therapeutic Range on Clinical Outcomes in Patients With Atrial Fibrillation Adherent to the Atrial Fibrillation Better Care Pathway: A Report From the COOL-AF Registry

Background We aimed to determine the effect of integrating Atrial Fibrillation Better Care pathway compliance in relation to achievement of systolic blood pressure (SBP) targets and good control of time in therapeutic range (TTR) on clinical outcomes in patients with atrial fibrillation. Methods and Results We prospectively enrolled patients with nonvalvular atrial fibrillation  from 27 hospitals in Thailand. All clinical outcomes were recorded. Main outcomes were the composite of all-cause death or ischemic stroke/systemic embolism (SSE), as well as secondary outcomes of all-cause death, SSE, major bleeding, intracranial hemorrhage, and heart failure. An SBP of 120 to 140 mm Hg was considered good blood pressure control. Target TTR was a TTR ≥65%. A total of 3405 patients were studied (mean age 67.8 years, 41.8% female). Full ABC pathway compliance was evident in 42.7%. For blood pressure control, 41.9% had SBP within target, whereas 35.9% of those on warfarin had TTR within target. The incidence rates of all-cause death/SSE, all-cause death, SSE, major bleeding, intracranial hemorrhage, and heart failure were 5.29, 4.21, 1.51, 2.25, 0.78, and 2.84 per 100 person-years respectively. Adjusted hazard ratios and 95% CI of Atrial Fibrillation Better Care pathway compliance for all-cause death/SSE, all-cause death, and heart failure were 0.76 (0.62-0.94), 0.79 (0.62-0.99), and 0.69 (0.51-0.94), respectively, compared with noncompliance. Patients with Atrial Fibrillation Better Care compliance and SBP within target had a better outcome or TTR within target had better outcomes. Conclusions In COOL-AF (Cohort of Antithrombotic Use and Optimal International Normalized Ratio Level in Patients With Non-Valvular Atrial Fibrillation in Thailand), a multicenter nationwide prospective cohort of patients with atrial fibrillation, achieving SBP within target and TTR ≥ 65% has added value to Atrial Fibrillation Better Care pathway compliance in the reduction of adverse clinical outcomes in patients with atrial fibrillation.

A Bionic Testbed for Cardiac Ablation Tools

Bionic-engineered tissues have been proposed for testing the performance of cardiovascular medical devices and predicting clinical outcomes ex vivo. Progress has been made in the development of compliant electronics that are capable of monitoring treatment parameters and being coupled to engineered tissues; however, the scale of most engineered tissues is too small to accommodate the size of clinical-grade medical devices. Here, we show substantial progress toward bionic tissues for evaluating cardiac ablation tools by generating a centimeter-scale human cardiac disk and coupling it to a hydrogel-based soft-pressure sensor. The cardiac tissue with contiguous electromechanical function was made possible by our recently established method to 3D bioprint human pluripotent stem cells in an extracellular matrix-based bioink that allows for in situ cell expansion prior to cardiac differentiation. The pressure sensor described here utilized electrical impedance tomography to enable the real-time spatiotemporal mapping of pressure distribution. A cryoablation tip catheter was applied to the composite bionic tissues with varied pressure. We found a close correlation between the cell response to ablation and the applied pressure. Under some conditions, cardiomyocytes could survive in the ablated region with more rounded morphology compared to the unablated controls, and connectivity was disrupted. This is the first known functional characterization of living human cardiomyocytes following an ablation procedure that suggests several mechanisms by which arrhythmia might redevelop following an ablation. Thus, bionic-engineered testbeds of this type can be indicators of tissue health and function and provide unique insight into human cell responses to ablative interventions.

Adolescent Persistent Atrial Fibrillation Concomitant with Pectus Excavatum

A 19-year-old man with pectus excavatum developed symptomatic persistent atrial fibrillation (AF). He had no remarkable medical history or comorbidities and had not exercised intensely during childhood. Electrical cardioversion and pre-treatment with amiodarone for two months failed to maintain sinus rhythm. Computed tomography before ablation revealed compression of the right and left atria between the sternal bone and vertebral bodies. Voltage mapping revealed that the right and left atrial voltages were preserved within the normal limit. However, radiofrequency catheter ablation successfully eliminated recurrent persistent AF. No recurrence was observed during eight months of follow-up.

Atrial Fibrillation in a Patient with Heparin-induced Thrombocytopenia Successfully Treated by Radiofrequency Catheter Ablation Using a Direct Thrombin Inhibitor

A 74-year-old man was admitted to our hospital to undergo radiofrequency catheter ablation (RFCA) of persistent atrial fibrillation (AF). We found that he had a history of heparin-induced thrombocytopenia (HIT). Thus, a direct thrombin inhibitor, Argatroban Hydrate (Argatroban^®), was used instead of heparin as anticoagulation therapy during the RFCA procedure. Finally, the AF was successfully treated by RFCA without any complications. Given these findings, the direct thrombin inhibitor Argatroban^® may be effective and feasible for anticoagulation therapy during RFCA procedures for AF in patients with HIT, such as the present case.

The impact of the atrial wall thickness in normal/mild late-gadolinium enhancement areas on atrial fibrillation rotors in persistent atrial fibrillation patients

Background

Some of atrial fibrillation (AF) drivers are found in normal/mild late-gadolinium enhancement (LGE) areas, as well as moderate ones. The atrial wall thickness (AWT) has been reported to be important as a possible AF substrate. However, the AWT and degree of LGEs as an AF substrate has not been fully validated in humans.

Objective

The purpose of this study was to evaluate the impact of the AWT in normal/mild LGE areas on AF drivers.

Methods

A total of 287 segments in 15 persistent AF patients were assessed. AF drivers were defined as non-passively activated areas (NPAs), where rotational activation was frequently observed, and were detected by the novel real-time phase mapping (ExTRa Mapping), mild LGE areas were defined as areas with a volume ratio of the enhancement voxel of 0% to <10%. The AWT was defined as the minimum distance from the manually determined endocardium to the epicardial border on the LGE-MRI.

Results

NPAs were found in 20 (18.0%) of 131 normal/mild LGE areas where AWT was significantly thicker than that in the passively activated areas (PAs) (2.5 ± 0.3 vs. 2.2 ± 0.3 mm, p < .001). However, NPAs were found in 41 (26.3%) of 156 moderate LGE areas where AWT was thinner than that of PAs (2.1 ± 0.2 mm vs. 2.23 ± 0.3 mm, p = .02). An ROC curve analysis yielded an optimal cutoff value of 2.2 mm for predicting the presence of an NPA in normal/mild LGE areas.

Conclusion

The location of AF drivers in normal/mild LGE areas might be more accurately identified by evaluating AWT.

A Review on Atrial Fibrillation (Computer Simulation and Clinical Perspectives)

Atrial fibrillation (AF), a heart condition, has been a well-researched topic for the past few decades. This multidisciplinary field of study deals with signal processing, finite element analysis, mathematical modeling, optimization, and clinical procedure. This article is focused on a comprehensive review of journal articles published in the field of AF. Topics from the age-old fundamental concepts to specialized modern techniques involved in today’s AF research are discussed. It was found that a lot of research articles have already been published in modeling and simulation of AF. In comparison to that, the diagnosis and post-operative procedures for AF patients have not yet been totally understood or explored by the researchers. The simulation and modeling of AF have been investigated by many researchers in this field. Cellular model, tissue model, and geometric model among others have been used to simulate AF. Due to a very complex nature, the causes of AF have not been fully perceived to date, but the simulated results are validated with real-life patient data. Many algorithms have been proposed to detect the source of AF in human atria. There are many ablation strategies for AF patients, but the search for more efficient ablation strategies is still going on. AF management for patients with different stages of AF has been discussed in the literature as well but is somehow limited mostly to the patients with persistent AF. The authors hope that this study helps to find existing research gaps in the analysis and the diagnosis of AF.

Recent advances in gene therapy for atrial fibrillation

Atrial fibrillation (AF) is the most common heart rhythm disorder in adults and a major cause of stroke. Unfortunately, current treatments for AF are suboptimal as they are not targeting the molecular mechanisms underlying AF. In this regard, gene therapy is emerging as a promising approach for mechanism-based treatment of AF. In this review, we summarize recent advances and challenges in gene therapy for this important cardiovascular disease.

Atrial Fibrillation Recurrence Prevention after Electrical Cardioversion in High-Risk Patients – Benefits of Non-Antiarrhythmic Drugs

Background:

Recurrence prevention after Atrial Fibrillation (AF) termination by Eelectrical Cardioversion (ECV) remains challenging. Increasing attention is paid to pathophysiological effects of non-Antiarrhythmic Drugs (non-AADs), nevertheless, with heterogeneous results.

Objective:

We evaluated the potential benefits of different non-AADs as adjunctive therapy to Antiarrhythmic Drugs (AADs) for AF recurrence prevention after sinus rhythm restoration by ECV in high-risk patients.

Methods:

The study was conducted among high-risk AF patients after successful ECV. Prescription of class IC or class III AAD was required. Data were acquired in a face-to-face baseline interview and 1-, 3-, 6-, 9-, 12-month follow-up interviews.

Results:

113 patients were included. Total AF recurrence rate reached 48.7%. Angiotensin-Converting Enzyme Inhibitor (ACEI) or angiotensin receptor blocker (ARB) intake, compared with non-use, demonstrated AF recurrence rate reduction by 8.5% (46.3 vs. 54.8%), with odds ratio (OR) reduced by 28.9% (OR 0.711, 95% confidence interval (CI) 0.310-1.631, p = 0.420). Among mineralocorticoid receptor antagonist (MRA) users, AF recurrence rate was reduced by 25.1% (29.6 vs. 54.7%) and OR by 65.1% (OR 0.349, 95%CI 0.138-0.884, p = 0.023). Present statin therapy reduced AF recurrence rate by 4.2% (46.8 vs. 51.0%) and OR by 15.5% (OR 0.845, 95%CI 0.402-1.774, p = 0.656). Diuretic use showed reduction of AF recurrence rate by 10.2% (41.7 vs. 51.9%) and OR by 33.9% (OR 0.661, 95%CI 0.297-1.469, p = 0.308).

Conclusion:

Non-AADs demonstrated practical benefits as adjunctive therapy to AADs for AF recurrence prevention after ECV in high-risk patients, with statistically significant results established for concomitant MRA intake.

Early Risk of Stroke in Patients Undergoing Acute Versus Elective Cardioversion for Atrial Fibrillation

Background

Electrical cardioversion (ECV) is routinely used to restore sinus rhythm in patients with symptomatic atrial fibrillation. The European guidelines have been updated in recent years. Current information on differences in the risk for stroke after acute versus elective ECV is lacking.

Methods And Results

All patients with a first‐time acute or elective ECV in the Stockholm regional health care data warehouse from 2011 to 2018 were included. Cox regression analyses were performed evaluating ischemic or unspecified stroke within 30 days after ECV with adjustments for the CHA₂DS₂‐VASc score, medical treatment, and year of inclusion. The study included 9139 patients, 3094 after acute and 6045 after elective ECV. The mean age was 65.9±11.3 years, 69.5% were men, and the mean CHA₂DS₂‐VASc score was 2.4±1.7. Before the intervention, 49.6% of patients with an acute ECV and 96.4% of those with an elective ECV had claimed an oral anticoagulant prescription. Ischemic or unspecified stroke occurred in 26 (0.28%) patients within 30 days. The unadjusted risk was higher after acute compared with elective ECV (hazard ratio [HR], 2.29; 95% CI, 1.06–4.96), whereas there was no difference after multivariable adjustments (adjusted HR, 0.99; 95% CI, 0.36–2.72). Both non–vitamin K oral anticoagulants (adjusted HR, 0.28; 95% CI, 0.08–0.98) and warfarin (adjusted HR, 0.17; 95% CI, 0.05–0.53) were associated with a lower risk for stroke compared with no anticoagulation.

Conclusions

Acute ECV was associated with a higher unadjusted risk for stroke than elective ECV, but the risk was similar after adjustment for anticoagulant treatment. This study indicates the importance of anticoagulation before ECV according to recent European guidelines.

Safety and Efficacy of Ibutilide for Acute Pharmacological Cardioversion of Rheumatic Atrial Fibrillation

INTRODUCTION

Ibutilide is indicated for acute cardioversion of nonvalvular atrial fibrillation (AF). However, its efficacy and safety in the pharmacological cardioversion of rheumatic AF are unknown.

METHODS

Patients with mild-to-moderate rheumatic mitral valve (MV) disease with symptomatic, paroxysmal, or persistent AF were included in the analysis. Intravenous ibutilide was administered at doses tailored to body weight (0.5-2.0 mg) for over 10 min. The primary end point was efficacy, assessed as the rate of conversion of AF to sinus rhythm. The secondary end point was safety, including arrhythmic events and death within 24 h of drug initiation.

RESULTS

From June 2016 to October 2018, 165 patients (94 with mitral stenosis, 23 with mitral regurgitation, 11 with mixed MV disease, and 37 with MV replacement) received ibutilide (mean dose 0.90 ± 0.54 mg). Ibutilide successfully converted AF to sinus rhythm in 127/165 (76.9%) patients, with a conversion time of 7.9 ± 4.1 min. The QTc increased from 419.9 ± 15.8 to 487.5 ± 34 ms after ibutilide administration (p < 0.001). The mean change in QTc after ibutilide administration (∆QTc) was 72.01 ± 36.03. There were no deaths, but 3 patients (1.8%) developed torsades de pointes (TdP) requiring defibrillation 55 ± 37 min after infusion.

CONCLUSION

Ibutilide cardioverted 77% of rheumatic AF to sinus rhythm, indicating its potential as a clinically useful option for pharmacological cardioversion of rheumatic AF. TdP is a potentially serious adverse event that requires careful monitoring.

Investigation of the arcane inhibition of human organic anion transporter 3 by benzofuran antiarrhythmic agents

The combination of antiarrhythmic agents, amiodarone or dronedarone, with the anticoagulant rivaroxaban is used clinically in the management of atrial fibrillation for rhythm control and secondary stroke prevention respectively. Renal drug-drug interactions (DDIs) between amiodarone or dronedarone and rivaroxaban were previously ascribed to inhibition of rivaroxaban secretion by P-glycoprotein at the apical membrane of renal proximal tubular epithelial cells. Benzbromarone, a known inhibitor of organic anion transporter 3 (OAT3), shares a benzofuran scaffold with amiodarone and dronedarone. However, inhibitory activity of amiodarone and dronedarone against OAT3 remains arcane. Here, we conducted in vitro transporter inhibition assays in OAT3-transfected HEK293 cells which revealed amiodarone, dronedarone and their respective major pharmacologically-active metabolites N-desethylamiodarone and N-desbutyldronedarone possess inhibitory activity against OAT3, with corrected K_i values of 0.042, 0.019, 0.028 and 0.0046 μM respectively. Protein binding effects and probe substrate dependency were accounted for in our assays. Static modelling predicted 1.29-, 1.01-, 1.29- and 1.16-fold increase in rivaroxaban exposure, culminating in a predicted 1.29-, 1.01-, 1.28- and 1.15-fold increase in major bleeding risk respectively, suggesting potential OAT3-mediated DDI between amiodarone and rivaroxaban. Future work involving physiologically-based pharmacokinetic modelling is crucial in holistically predicting the complex DDIs between the benzofuran antiarrhythmic agents and rivaroxaban.

The 4S-AF Scheme (Stroke Risk; Symptoms; Severity of Burden; Substrate): A Novel Approach to In-Depth Characterization (Rather than Classification) of Atrial Fibrillation

Atrial fibrillation (AF) is a complex condition requiring holistic management with multiple treatment decisions about optimal thromboprophylaxis, symptom control (and prevention of AF progression), and identification and management of concomitant cardiovascular risk factors and comorbidity. Sometimes the information needed for treatment decisions is incomplete, as available classifications of AF mostly address a single domain of AF (or patient)-related characteristics. The most widely used classification of AF based on AF episode duration and temporal patterns (that is, the classification to first-diagnosed, paroxysmal, persistent/long-standing persistent, and permanent AF) has contributed to a better understanding of AF prevention and treatment but its limitations and the need for a multidimensional AF classification have been recognized as more complex treatment options became available. We propose a paradigm shift from classification toward a structured characterization of AF, addressing specific domains having treatment and prognostic implications to become a standard in clinical practice, thus aiming to streamline the assessment of AF patients at all health care levels facilitating communication among physicians, treatment decision-making, and optimal risk evaluation and management of AF patients. Specifically, we propose the 4S-AF structured pathophysiology-based characterization (rather than classification) scheme that includes four AF- and patient-related domains-Stroke risk, Symptoms, Severity of AF burden, and Substrate severity-and provide a hypothetical model for the use of 4S-AF characterization scheme to aid treatment decision making concerning the management of patients with AF in clinical practice.

Integrated Care in Atrial Fibrillation: A Road Map to the Future

Atrial fibrillation (AF) is the most commonly encountered arrhythmia in clinical practice with an epidemiological coupling appreciated with advancing age, cardiometabolic risk factors, and structural heart disease. This has resulted in a significant public health burden over the years, evident through increasing rates of hospitalization and AF-related clinical encounters. The resultant gap in health care outcomes is largely twinned with suboptimal rates of anticoagulation prescription and adherence, deficits in symptom identification and management, and insufficient comorbid cardiovascular risk factor investigation and modification. In view of these shortfalls in care, the establishment of integrated chronic care models serves as a road map to best clinical practice. The expansion of integrated chronic care programs, which include multidisciplinary team care, nurse-led AF clinics, and use of telemedicine, are expected to improve AF-related outcomes in the coming years. This review will delve into current gaps in AF care and the role of integrated chronic care models in bridging fragmentations in its management.

Late-gadolinium enhancement properties associated with atrial fibrillation rotors in patients with persistent atrial fibrillation

BACKGROUND

A computational model demonstrated that atrial fibrillation (AF) rotors could be distributed in patchy late-gadolinium enhancement (LGE) areas and play an important role in AF drivers. However, this was not validated in humans.

OBJECTIVE

The purpose of this study was to evaluate the LGE properties of AF rotors in patients with persistent AF.

METHODS

A total of 287 segments in 15 patients with persistent AF (long-standing persistent AF in 9 patients) that underwent AF ablation were assessed. Non-passively activated areas (NPAs), where rotational activation (AF rotor) was frequently observed, were detected by the novel real-time phase mapping (ExTRa Mapping). The properties of the LGE areas were assessed using the LGE heterogeneity and the density which was evaluated by the entropy (LGE-entropy) and the volume ratio of the enhancement voxel (LGE-volume ratio), respectively.

RESULTS

NPAs were found in 61 (21%) of 287 segments and were mostly found around the pulmonary vein antrum. A receiver operating characteristic curve analysis yielded an optimal cutoff value of 5.7% and 10% for the LGE-entropy and LGE-volume ratio, respectively. The incidence of NPAs was significantly higher at segments with an LGE-entropy of >5.7 and LGE-volume ratio of >10% than at the other segments (38 [30%] of 126 vs. 23 [14%] of 161 segments; p = .001). No NPAs were found at segments with an LGE-volume ratio of >50% regardless of the LGE-entropy. Of five patients with AF recurrence, NPAs outside the PV antrum were not ablated in three patients and the remaining NPAs were ablated, but their LGE-entropy and LGE-volume ratio were low.

CONCLUSION

AF rotors are mostly distributed in relatively weak and much more heterogenous LGE areas.

Integrative Identification of Hub Genes Associated With Immune Cells in Atrial Fibrillation Using Weighted Gene Correlation Network Analysis

Background: Atrial fibrillation (AF) is the most common tachyarrhythmia in the clinic, leading to high morbidity and mortality. Although many studies on AF have been conducted, the molecular mechanism of AF has not been fully elucidated. This study was designed to explore the molecular mechanism of AF using integrative bioinformatics analysis and provide new insights into the pathophysiology of AF. Methods: The GSE115574 dataset was downloaded, and Cibersort was applied to estimate the relative expression of 22 kinds of immune cells. Differentially expressed genes (DEGs) were identified through the limma package in R language. Weighted gene correlation network analysis (WGCNA) was performed to cluster DEGs into different modules and explore relationships between modules and immune cell types. Functional enrichment analysis was performed on DEGs in the significant module, and hub genes were identified based on the protein-protein interaction (PPI) network. Hub genes were then verified using quantitative real-time polymerase chain reaction (qRT-PCR). Results: A total of 2,350 DEGs were identified and clustered into eleven modules using WGCNA. The magenta module with 246 genes was identified as the key module associated with M1 macrophages with the highest correlation coefficient. Three hub genes (CTSS, CSF2RB, and NCF2) were identified. The results verified using three other datasets and qRT-PCR demonstrated that the expression levels of these three genes in patients with AF were significantly higher than those in patients with SR, which were consistent with the bioinformatic analysis. Conclusion: Three novel genes identified using comprehensive bioinformatics analysis may play crucial roles in the pathophysiological mechanism in AF, which provide potential therapeutic targets and new insights into the treatment and early detection of AF.

Pleiotropic activity of nerve growth factor in regulating cardiac functions and counteracting pathogenesis

Cardiac innervation density generally reflects the levels of nerve growth factor (NGF) produced by the heart—changes in NGF expression within the heart and vasculature contribute to neuronal remodelling (e.g. sympathetic hyperinnervation or denervation). Its synthesis and release are altered under different pathological conditions. Although NGF is well known for its survival effects on neurons, it is clear that these effects are more wide ranging. Recent studies reported both in vitro and in vivo evidence for beneficial actions of NGF on cardiomyocytes in normal and pathological hearts, including prosurvival and antiapoptotic effects. NGF also plays an important role in the crosstalk between the nervous and cardiovascular systems. It was the first neurotrophin to be implicated in postnatal angiogenesis and vasculogenesis by autocrine and paracrine mechanisms. In connection with these unique cardiovascular properties of NGF, we have provided comprehensive insight into its function and potential effect of NGF underlying heart sustainable/failure conditions. This review aims to summarize the recent data on the effects of NGF on various cardiovascular neuronal and non‐neuronal functions. Understanding these mechanisms with respect to the diversity of NGF functions may be crucial for developing novel therapeutic strategies, including NGF action mechanism‐guided therapies.

Renal Dysfunction following Direct Current Cardioversion of Atrial Fibrillation: Incidence and Risk Factors

INTRODUCTION

Emerging data suggest that cardioversion for atrial fibrillation (AF) may be associated with acute kidney injury (AKI). However, limited data are available regarding the incidence and risk factors for AKI after direct current cardioversion (DCCV) of AF.

METHODS

All patients undergoing DCCV at Mayo Clinic between 2001 and 2012 for AF were prospectively enrolled in a database. All patients with serum creatinine (SCR) values pre- and post-cardioversion were reviewed for AKI, defined as a ≥25% decline in eGFR (estimated glomerular filtration rate) from baseline value within 7 days of the DCCV.

RESULTS

Of the 6,427 eligible patients, 1,256 (19.5%) patients had pre- and post-DCCV SCR available and formed the cohort under study. The mean age was 70.4 (SD 11.7) years, and 67.3% were male. During the study period, 131 (10.4%) patients suffered from AKI following DCCV. AKI was independently associated with inpatient status (OR 26.79; 95% CI 3.69-194.52), CHA2DS2-VASc score (OR 1.25; 95% CI 1.11-1.41), prior use of diuretics (OR 1.59; 95% CI 1.03-2.46), and absence of CKD (OR 1.61; 95% CI 1.04-2.49), and was independent of the success of the DCCV. None of the patients required acute dialysis during the study outcome period.

CONCLUSION

AKI following DCCV of AF is common, self-limited, and without the need for replacement therapies.

Association between use of amiodarone for non-valvular atrial fibrillation and patient survival: from the prospective China Atrial Fibrillation Registry

Background

Post hoc analysis of the landmark atrial fibrillation follow-up investigation of rhythm management trial revealed that amiodarone was associated with higher risks of mortality, intensive care unit admission, and non-cardiovascular death. We aim to evaluate the association between amiodarone use and patient survival under updated medical mode and level using data from the China Atrial Fibrillation (China-AF) Registry study.

Methods

Clinical data of 8161 non-valvular atrial fibrillation (NVAF) patients who were antiarrhythmic drug (AAD)-naive before enrollment into the China-AF Registry, recruited between August 2011 and February 2017, were collected. The primary outcome was all-cause mortality. A Cox proportional hazard regression model was used to evaluate the association between amiodarone use and the outcome. We also calculated the rate of sinus rhythm maintenance at the penultimate follow-up.

Results

Compared with 6167 patients of non-AAD group, 689 patients of the amiodarone group were younger (mean age 65.6 vs. 68.6 years), more frequently completed high school education, had fewer comorbidities such as chronic heart failure, prior bleeding, and stroke, and were more likely to be treated in tertiary hospitals while less hospitalization. The proportion of persistent AF was much lower among users of amiodarone, who were also less likely to be taking oral anticoagulants. The patients in the amiodarone group had a statistically insignificant lower incidence of all-cause mortality (2.44 vs. 3.91 per 100 person-years) over a mean follow-up duration of 300.6 ± 77.5 days. After adjusting for potential confounders, amiodarone use was not significantly associated with a lower risk of all-cause mortality (adjusted hazard ratio, 0.79; 95% confidence interval, 0.42–1.49). Sub-group analysis revealed the consistent results. The rate of sinus rhythm maintenance at the penultimate follow-up in the amiodarone group was significantly higher than in the non-AAD group.

Conclusions

Our study indicated that amiodarone use was not significantly associated with a lower risk of 1-year all-cause mortality compared with a non-AAD strategy in “real-world” patients with NVAF.

Evaluation of Coronary Artery Disease in Patients with Atrial Fibrillation by Cardiac Computed Tomography for Catheter Ablation: CADAF-CT Trial 2

Objective We recently reported that routine cardiac computed tomography (CT) scans for radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) could steadily detect coronary artery lesions (CALs) and could accurately detect myocardial ischemia in 9% of patients with AF who underwent RFCA of AF. The aim of this study was to identify the independent risk factor (s) of myocardial ischemia in those patients. Methods Patient characteristics, blood test, CALs, Ordinal coronary calcium scoring (OCCS), and myocardial Ischemia (MI) were evaluated in 757 consecutive patients who underwent RFCA of AF. Results There were 685 and 72 patients without and with myocardial ischemia, respectively. A univariate analysis and multivariate statistical analysis revealed that a male gender (Odds ratio 2.11), a high number of co-existing coronary risk factors (NCCRF ≥3) (Odds ratio 2.03), an elevated brain natriuretic peptide level (BNP ≥100 pg/mL) (Odds ratio 3.37), an enlarged left atrial volume (≥90 mL) (Odds ratio 2.91), and a high OCCS (≥4) (Odds ratio 13.0) were independent risk factors of myocardial ischemia in patients undergoing RFCA of AF. Conclusion The high OCCS (≥4) by cardiac CT was the strongest independent risk factor of myocardial ischemia in those patients. However, physicians may be able to find the high risk patients of myocardial ischemia by evaluating a male gender, in the presence of a high NCCRF (≥3) and elevated BNP (≥100 pg/mL) without OCCS by cardiac CT in patients undergoing RFCA of AF.

Identification of Biomarkers Related to Atrial Fibrillation With Mitral Regurgitation

BACKGROUND

We aimed to explore the biomarkers associated with atrial fibrillation (AF) with mitral regurgitation (MR).

METHODS

The gene expression profile data GSE115574 were downloaded from Gene Expression Omnibus database, which were obtained from patients with degenerative MR with AF and sinus rhythm (SR). The differentially expressed genes (DEGs) in samples of AF with MR compared with those of SR with MR were selected, followed by functional enrichment analysis, protein-protein interaction (PPI) network analysis, transcription factor (TF) prediction, and drug-gene interaction prediction.

RESULTS

By comparing the genes' expression profiles between AF with MR and SR with MR, 379 DEGs were obtained. The upregulated genes, such as NMNAT2, LDHB, and hexosaminidase subunit beta (HEXB), were significantly enriched in metabolic pathways. Hub genes, such as amyloid beta precursor protein (APP), CDH2, SPP1, and STC2, were significantly associated with functions related to extracellular matrix organization and vitamin D response. Additionally, two TFs, PRDM3 and LSM6, were predicted for the key module genes. APP predicted the most drug molecules, that is, 22 molecules, and SPP1 predicted 10 drug molecules.

CONCLUSIONS

Dysregulation of the metabolic pathway may play a critical role in AF with MR. Changes in functions related to the extracellular matrix and vitamin D response may also be associated with AF progression in patients with MR. Furthermore, APP, STC2, and SPP1 may serve as potential therapeutic targets of AF.

Treatment strategies for new-onset atrial fibrillation in critically ill patients: Protocol for a systematic review

BACKGROUND

New-onset atrial fibrillation is frequent in critically ill patients and associated with poorer outcomes in these patients. Numerous interventions are used for the management of new-onset atrial fibrillation, but it is unknown if these interventions improve patient-important outcomes as compared with placebo or no active intervention in adult critically ill patients.

METHODS/DESIGN

We will conduct a systematic review with meta-analysis and trial sequential analysis of randomized clinical trials assessing pharmacological and non-pharmacological interventions of new-onset atrial fibrillation as compared with placebo or no active intervention in adult critically ill patients. The primary outcomes are mortality, adverse events and health-related quality of life. We will search the following databases: MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov, Science Citation Index and BIOSIS and follow the recommendations by the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We will evaluate the overall certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

DISCUSSION

New-onset atrial fibrillation is common in adult critically ill patients. However, the balance between the desirable and undesirable effects of pharmacological and non-pharmacological interventions is unknown. The outlined systematic review aims to provide updated data on this topic.

REGISTRATION

Submitted to PROSPERO (CRD42020187178 ). Status: accepted.

Attenuation of Oxidative Injury With Targeted Expression of NADPH Oxidase 2 Short Hairpin RNA Prevents Onset and Maintenance of Electrical Remodeling in the Canine Atrium: A Novel Gene Therapy Approach to Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common heart rhythm disorder in adults and a major cause of stroke. Unfortunately, current treatments of AF are suboptimal because they are not targeted to the molecular mechanisms underlying AF. Using a highly novel gene therapy approach in a canine, rapid atrial pacing model of AF, we demonstrate that NADPH oxidase 2 (NOX2) generated oxidative injury causes upregulation of a constitutively active form of acetylcholine-dependent K+ current (IKACh), called IKH; this is an important mechanism underlying not only the genesis, but also the perpetuation of electric remodeling in the intact, fibrillating atrium.

METHODS

To understand the mechanism by which oxidative injury promotes the genesis and maintenance of AF, we performed targeted injection of NOX2 short hairpin RNA (followed by electroporation to facilitate gene delivery) in atria of healthy dogs followed by rapid atrial pacing. We used in vivo high-density electric mapping, isolation of atrial myocytes, whole-cell patch clamping, in vitro tachypacing of atrial myocytes, lucigenin chemiluminescence assay, immunoblotting, real-time polymerase chain reaction, immunohistochemistry, and Masson trichrome staining.

RESULTS

First, we demonstrate that generation of oxidative injury in atrial myocytes is a frequency-dependent process, with rapid pacing in canine atrial myocytes inducing oxidative injury through the induction of NOX2 and the generation of mitochondrial reactive oxygen species. We show that oxidative injury likely contributes to electric remodeling in AF by upregulating IKACh by a mechanism involving frequency-dependent activation of PKCε (protein kinase C epsilon). The time to onset of nonsustained AF increased by >5-fold in NOX2 short hairpin RNA-treated dogs. Furthermore, animals treated with NOX2 short hairpin RNA did not develop sustained AF for up to 12 weeks. The electrophysiological mechanism underlying AF prevention was prolongation of atrial effective refractory periods, at least in part attributable to the attenuation of IKACh. Attenuated membrane translocation of PKCε appeared to be a likely molecular mechanism underlying this beneficial electrophysiological remodeling.

CONCLUSIONS

NOX2 oxidative injury (1) underlies the onset, and the maintenance of electric remodeling in AF, as well, and (2) can be successfully prevented with a novel, gene-based approach. Future optimization of this approach may lead to a novel, mechanism-guided therapy for AF.

Antiarrhythmic and cardiac electrophysiological effects of SZV-270, a novel compound with combined Class I/B and Class III effects, in rabbits and dogs

Cardiovascular diseases are the leading causes of mortality. Sudden cardiac death is most commonly caused by ventricular fibrillation (VF). Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major cause of stroke and heart failure. Pharmacological management of VF and AF remains suboptimal due to limited efficacy of antiarrhythmic drugs and their ventricular proarrhythmic adverse effects. In this study, the antiarrhythmic and cardiac cellular electrophysiological effects of SZV-270, a novel compound, were investigated in rabbit and canine models. SZV-270 significantly reduced the incidence of VF in rabbits subjected to coronary artery occlusion/reperfusion and reduced the incidence of burst-induced AF in a tachypaced conscious canine model of AF. SZV-270 prolonged the frequency-corrected QT interval, lengthened action potential duration and effective refractory period in ventricular and atrial preparations, blocked I _Kr in isolated cardiomyocytes (Class III effects), and reduced the maximum rate of depolarization (V _max) at cycle lengths smaller than 1000 ms in ventricular preparations (Class I/B effect). Importantly, SZV-270 did not provoke Torsades de Pointes arrhythmia in an anesthetized rabbit proarrhythmia model characterized by impaired repolarization reserve. In conclusion, SZV-270 with its combined Class I/B and III effects can prevent reentry arrhythmias with reduced risk of provoking drug-induced Torsades de Pointes.

Efficacy and safety of ShenSongYangXin Capsule combined with antiarrhythmic drugs for atrial fibrillation: A protocol for systematic review and network meta-analysis

BACKGROUND

Shen-Song-Yang-Xin Capsule (SSYX), a Chinese patent medicine, combined with antiarrhythmic drugs (AADs) in the treatment of atrial fibrillation (AF) has been widely applied in clinical practice, but the results are controversial. This study aims to conduct a network meta-analysis (NMA) based on data from the randomized controlled trials (RCTs) to evaluate the efficacy and safety of SSYX combined with ADDs in the treatment of AF.

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 RCTs about SSYX combined with ADDs. The primary outcomes will be the frequency of AF attack and P-wave dispersion, and the secondary outcomes will be the symptom improvements, left atrial diameter, and adverse events. Statistical analyses will be conducted by using WinBUGS software (version 1.4.3), 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 SSYX 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 SSYX for AF. INTERNATIONAL PLATFORM OF REGISTERED SYSTEMATIC REVIEW AND META-ANALYSIS PROTOCOLS (INPLASY) REGISTRATION NUMBER:: The protocol of this systematic review and meta-analysis was registered on the INPLASY website (https://inplasy.com/inplasy-2020-8-0075/) and INPLASY registration number is INPLASY202080075.

Multi-scale Entropy Evaluates the Proarrhythmic Condition of Persistent Atrial Fibrillation Patients Predicting Early Failure of Electrical Cardioversion

Atrial fibrillation (AF) is nowadays the most common cardiac arrhythmia, being associated with an increase in cardiovascular mortality and morbidity. When AF lasts for more than seven days, it is classified as persistent AF and external interventions are required for its termination. A well-established alternative for that purpose is electrical cardioversion (ECV). While ECV is able to initially restore sinus rhythm (SR) in more than 90% of patients, rates of AF recurrence as high as 20-30% have been found after only a few weeks of follow-up. Hence, new methods for evaluating the proarrhythmic condition of a patient before the intervention can serve as efficient predictors about the high risk of early failure of ECV, thus facilitating optimal management of AF patients. Among the wide variety of predictors that have been proposed to date, those based on estimating organization of the fibrillatory (f-) waves from the surface electrocardiogram (ECG) have reported very promising results. However, the existing methods are based on traditional entropy measures, which only assess a single time scale and often are unable to fully characterize the dynamics generated by highly complex systems, such as the heart during AF. The present work then explores whether a multi-scale entropy (MSE) analysis of the f-waves may provide early prediction of AF recurrence after ECV. In addition to the common MSE, two improved versions have also been analyzed, composite MSE (CMSE) and refined MSE (RMSE). When analyzing 70 patients under ECV, of which 31 maintained SR and 39 relapsed to AF after a four week follow-up, the three methods provided similar performance. However, RMSE reported a slightly better discriminant ability of 86%, thus improving the other multi-scale-based outcomes by 3-9% and other previously proposed predictors of ECV by 15-30%. This outcome suggests that investigation of dynamics at large time scales yields novel insights about the underlying complex processes generating f-waves, which could provide individual proarrhythmic condition estimation, thus improving preoperative predictions of ECV early failure.

How to Manage Atrial Fibrillation in the Emergency Department: a Critical Appraisal

Atrial fibrillation is the most common cardiac arrhythmia in emergency departments. There is growing evidence that certain patients with acute atrial fibrillation can be safely managed in the emergency room without the need for hospitalization, minimizing costs and reducing unnecessary exposures. This review addresses the emergency management of atrial fibrillation based on the latest updates on the subject with a focus on the assessment and prevention of thromboembolic phenomena, control of frequency x control of rhythm and strategies for cardioversion and restoration of sinus rhythm or for heart rate control.

Cohort profile: the ESC EURObservational Research Programme Atrial Fibrillation III (AF III) Registry

Aims

The European Society of Cardiology (ESC) EURObservational Research Programme (EORP)-Atrial Fibrillation (AF) III Registry aims to identify contemporary patterns in AF management in clinical practice, assess their compliance with the 2016 ESC AF Guidelines, identify major gaps in guideline implementation, characterize the clinical practice settings associated with good vs. poor guideline implementation and assess and compare the 1-year outcome of guideline-adherent vs. guideline non-adherent management strategies.

Methods and results

Consecutive adult AF patients (n = 8306) were enrolled between 1 July 2018 and 15 July 2019, and individual patient data were prospectively collected across 192 centres and 31 participating countries during the 3-month enrolment period per centre. The Registry collected baseline and 1-year follow-up data in the eight main domains: patient demographic/enrolment setting, AF diagnosis/characterization, diagnostic assessment, stroke prevention treatments, arrhythmia-directed therapies, integrated AF management, major outcomes (death, non-fatal stroke or systemic embolic event, and non-fatal bleeding event), and the quality of life questionnaire.

Conclusion

The EORP-AF III Registry is an international, prospective registry of care and outcomes of patients treated for AF, which will provide insights into the contemporary patterns in AF management, ESC AF Guidelines implementation in routine practice and barriers to optimal management of this highly prevalent arrhythmia.

Multicellular In vitro Models of Cardiac Arrhythmias: Focus on Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice with a large socioeconomic impact due to its associated morbidity, mortality, reduction in quality of life and health care costs. Currently, antiarrhythmic drug therapy is the first line of treatment for most symptomatic AF patients, despite its limited efficacy, the risk of inducing potentially life-threating ventricular tachyarrhythmias as well as other side effects. Alternative, in-hospital treatment modalities consisting of electrical cardioversion and invasive catheter ablation improve patients' symptoms, but often have to be repeated and are still associated with serious complications and only suitable for specific subgroups of AF patients. The development and progression of AF generally results from the interplay of multiple disease pathways and is accompanied by structural and functional (e.g., electrical) tissue remodeling. Rational development of novel treatment modalities for AF, with its many different etiologies, requires a comprehensive insight into the complex pathophysiological mechanisms. Monolayers of atrial cells represent a simplified surrogate of atrial tissue well-suited to investigate atrial arrhythmia mechanisms, since they can easily be used in a standardized, systematic and controllable manner to study the role of specific pathways and processes in the genesis, perpetuation and termination of atrial arrhythmias. In this review, we provide an overview of the currently available two- and three-dimensional multicellular in vitro systems for investigating the initiation, maintenance and termination of atrial arrhythmias and AF. This encompasses cultures of primary (animal-derived) atrial cardiomyocytes (CMs), pluripotent stem cell-derived atrial-like CMs and (conditionally) immortalized atrial CMs. The strengths and weaknesses of each of these model systems for studying atrial arrhythmias will be discussed as well as their implications for future studies.

Evaluation of coronary artery disease in patients with atrial fibrillation by cardiac computed tomography for catheter ablation: CADAF-CT trial

Almost all institutions routinely perform cardiac computed tomography (CT) before radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) to evaluate the cardiac anatomy. The ideal timing of the CT image acquisition is different between for RFCA of AF and for evaluation of coronary artery lesions (CALs). Thus, the aim of this study was to assess whether 64- or 320-line routine cardiac CT scans before RFCA of AF could evaluate both coronary artery lesions and pulmonary veins (LA-PVs) anatomy at the timing of the image acquisition of the LA-PVs in patients with AF who underwent RFCA of AF. The CALs were evaluated in 606 consecutive patients who underwent RFCA of AF assessed by the ideal timing of the CT image acquisition for RFCA of AF, and myocardial ischemia (MI) was also evaluated in patients with severe coronary stenosis (≥ 50%) and unevaluable CALs due to their severe coronary calcification and banding artifact by additional examinations combined with exercise stress testing, ²⁰¹Tl scintigraphy, and/or fractionated flow reserve measurements. This study revealed that, in patients with AF who underwent RFCA of AF, (1) both 64- and 320-line cardiac CT scans for RFCA of AF could evaluate CALs in 93% of those patients, (2) the prevalence of MI was 9%, (3) significant relationships between the CHADS₂ score and prevalence of MI were observed (p = 0.003), and (4) the positive predict values of MI in patients with severe coronary stenosis (≥ 50%) and unevaluable CALs also significantly increased in accordance with the CHADS₂ score (p = 0.003). The evaluation of CALs and MI by routine cardiac CT for RFCA of AF combined with the additional examinations may be one of the most feasible modalities for patients with AF.

Higher Incidence of Asymptomatic Cerebral Emboli After Atrial Fibrillation Ablation Found With High-Resolution Diffusion-Weighted Magnetic Resonance Imaging

Background:

Asymptomatic cerebral emboli (ACE) are commonly seen on cerebral magnetic resonance imaging (MRI) after atrial fibrillation ablation, but the incidence in previous studies varies widely. No data exists to compare the effects of different diffusion-weighted imaging (DWI) settings on detecting ablation-related ACE. This self-control study sought to compare the incidence and characteristics of ablation-related ACE between high-resolution DWI and conventional DWI.

Methods:

A total of 55 consecutive patients referred for atrial fibrillation ablation between December 2017 and September 2018 were enrolled. Patients underwent high-resolution DWI 1 day before ablation and repeated high-resolution DWI and conventional DWI within 48 hours post-ablation. The incidence, number, size, and location of ACE were compared between 2 DWI settings in the same patients.

Results:

The high-resolution DWI revealed a higher incidence of acute ACE compared with conventional DWI (67.3% versus 41.8% of patients, P <0.001) and significantly more ACE (106 versus 45 lesions, P =0.001). For ACE seen on both scans, the size measured by high-resolution DWI was larger (5.42 versus 4.21 mm, P <0.001). No patients had any impaired neurocognitive performance during follow-up. Impaired left ventricular ejection fraction ( P =0.012) and low intraoperative activated clotting time ( P =0.009) level were associated with the occurrence of ACE in a multivariate analysis.

Conclusions:

High-resolution DWI revealed a higher incidence and greater details of post-ablation ACE in patients with atrial fibrillation. MRI settings significantly impact the detection of ACE and should be considered when comparing incidence rates of ACE among different studies.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01761188.

Identification of Long Non-Coding RNA and Circular RNA Expression Profiles in Atrial Fibrillation

BACKGROUND

Long non-coding RNA (lncRNA) and circular RNA (circRNA) have both been found to play important roles in cardiovascular diseases, including myocardial infarction, heart failure, and atherosclerosis. However, the role of lncRNA and circRNA in atrial fibrillation (AF) has rarely been investigated. This study aimed to identify lncRNA and circRNA expression profiles in AF patients.

METHODS

Atrial tissues from seven patients with AF and seven matched controls were collected. The lncRNA and circRNA expression profiles of atrial tissues were identified using Hiseq/Proton RNA sequencing. Validation was performed by reverse transcription quantitative real-time PCR (qRT-PCR) on 35 pairs of AF patients and controls. Gene Ontology (GO) categories and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. A competing endogenous RNA (ceRNA) network was constructed.

RESULTS

A total of 557 lncRNAs and 280 circRNAs were significantly differentially expressed with fold change >1.5 (p<0.05). An lncRNA Voltage Dependent Anion Channel 2 Pseudogene 2 (VDAC2P2) and two circRNAs chr13_41887361_41865736_-21625 and chr13_100368574_100301460_-67114 were validated, using qRT-PCR, to have significantly different expression levels. GO and KEGG pathway analysis showed that some pathways such as ribosome and chromatin modification, Rap1 signalling and cardiac muscle contraction were involved in the pathogenesis of AF. Competing endogenous RNAs were predicted based on constructional network analysis. The LncRNA-miRNA-mRNA and circRNA-miRNA-mRNA networks were constructed by co-expressing lncRNA/circRNA and mRNAs, which were competitively combined with miRNAs.

CONCLUSION

This study characterised lncRNA and circRNA expression and their interaction with mRNA and miRNA in AF.

Genetics of Atrial Fibrillation

Background

Atrial fibrillation (AF) is a common arrhythmia seen in clinical practice. Occasionally, no common risk factors are present in patients with this arrhythmia. This suggests the potential underlying role of genetic factors associated with predisposition to developing AF.

Methods and Results

We conducted a comprehensive review of the literature through large online libraries, including PubMed. Many different potassium and sodium channel mutations have been discussed in their relation to AF. There have also been non–ion channel mutations that have been linked to AF. Genome‐wide association studies have helped in identifying potential links between single‐nucleotide polymorphisms and AF. Ancestry studies have also highlighted a role of genetics in AF. Blacks with a higher percentage of European ancestry are at higher risk of developing AF. The emerging field of ablatogenomics involves the use of genetic profiles in their relation to recurrence of AF after catheter ablation.

Conclusions

The evidence for the underlying role of genetics in AF continues to expand. Ultimately, the role of genetics in risk stratification of AF and its recurrence is of significant interest. No established risk scores that are useful in clinical practice are present to date.